Paper scene: every line takes its width from its kind and line group (#4890 D2a, D2d) (#12232)

* Paper scene: kinds of line and their widths by ISO 128-20 (#4890 D2a)

A line's kind (visible, hidden, centre, thin) and a line group give its width in one place:
the standard's series of widths, and a group's wide and narrow lines two steps apart. Nothing
reads it yet; the next commit draws every line on paper from it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Paper scene: every line on paper takes its width from its kind and line group (#4890 D2d)

A view's lines and a dimension's lines are drawn in a line group: a visible edge is its wide
line, a hidden edge, a reference part's edge and a dimension's lines its narrow one, and a
hidden line is dashed 12 line widths on and 3 off. The five width constants that waited for
this go. Every caller draws in the default 0.5 mm group, so today's sheets are unchanged; a
drawing, a sheet and a view choose their own group next.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -4219,6 +4219,7 @@ dependencies = [
  "gethostname",
  "gltf",
  "log",
+ "png",
  "quick-xml",
  "rustix 1.1.5",
  "serde",
@@ -4229,8 +4230,10 @@ dependencies = [
  "solidcraft-geom",
  "solidcraft-kernel",
  "solidcraft-profile",
+ "solidcraft-sketch",
  "solidcraft-testkit",
  "thiserror 2.0.21",
+ "tiny-skia",
  "zip",
 ]
 
@@ -4294,6 +4297,7 @@ dependencies = [
  "harfrust",
  "serde",
  "serde_json",
+ "sha2 0.10.9",
  "solidcore-record",
  "solidcraft-geom",
  "thiserror 2.0.21",

ROADMAP.md

@@ -173,6 +173,12 @@ and the [foundation ledger](docs/drawing-foundations.md) track the bounded imple
 packages. The first geometry increment defines validated section records in a plane-local
 frame; the ledger separates that contract from section producers and the Drawing workspace.
 
+Drawing UI scaffold: the native workspace now supplies the shared four-tab ribbon,
+source Browser, compact dockable sheet strip and resizable Sheet Settings/options
+panel. Planned tools remain unavailable; only existing source services execute.
+Drawing files and paper rendering are still deferred. See the
+[UI implementation roadmap](docs/drawing-workspace-ui.md).
+
 Desktop view DXF export runs in the file-operation worker with five-stage progress and
 cooperative cancellation. Curve tolerance (0.0001–1 mm, default 0.01 mm) is remembered alongside
 the hidden-edge setting. Cancelled exports preserve the model and the previous destination;

apps/solidcraft-cli/src/crashes.rs

@@ -63,6 +63,10 @@ fn replay(report: &Value) -> Result<(), String> {
         Some(d) => super::load(d)?,
         None => solidcraft_engine::Session::default(),
     };
+    // The ids the session drew from there, so the commands give the same objects the same ids.
+    if let Some(seed) = script["ids"].as_u64() {
+        s.seed_ids(seed);
+    }
     std::panic::set_hook(Box::new(|info| {
         let loc = info.location().map_or_else(|| "(unknown)".to_string(), |l| format!("{}:{}", l.file(), l.line()));
         let msg = info.payload_as_str().unwrap_or("(not a text message)").to_string();

apps/solidcraft-cli/tests/run_results.rs

@@ -460,16 +460,13 @@ fn snapshot_runs_its_script_on_the_in_design() {
     }
 }
 
-/// An unknown command's error suggests the id that was meant.
+/// An unknown command's error suggests the id that was meant first; other close ids (such as
+/// `drawing.open`) may follow it.
 #[test]
 fn unknown_command_suggests_the_closest_id() {
     let output = cli().args(["exec", "file.open"]).output().unwrap();
     assert_eq!(output.status.code(), Some(1));
-    assert!(
-        String::from_utf8_lossy(&output.stderr).contains("did you mean `doc.open` or `panel.open`?"),
-        "{}",
-        String::from_utf8_lossy(&output.stderr)
-    );
+    assert!(String::from_utf8_lossy(&output.stderr).contains("did you mean `doc.open`"), "{}", String::from_utf8_lossy(&output.stderr));
 }
 
 /// #1833: `--timings` reports each command's time instead of the measurement, `--profile` adds

apps/solidcraft-web/index.html

@@ -26,6 +26,15 @@
   <link data-trunk rel="copy-file" href="../../assets/fonts/craft-ui-sc/OFL.txt" data-target-path="fonts/craft-ui-sc" />
   <link data-trunk rel="copy-file" href="../../assets/fonts/craft-ui-tc/CraftUI-TC.otf" data-target-path="fonts" />
   <link data-trunk rel="copy-file" href="../../assets/fonts/craft-ui-tc/OFL.txt" data-target-path="fonts/craft-ui-tc" />
+  <!-- A drawing's Arabic, Korean and Chinese text: each fetched once, when a drawing needs it. -->
+  <link data-trunk rel="copy-file" href="../../assets/fonts/noto-sans-arabic/NotoSansArabic-Regular.ttf" data-target-path="fonts/noto-sans-arabic" />
+  <link data-trunk rel="copy-file" href="../../assets/fonts/noto-sans-arabic/OFL.txt" data-target-path="fonts/noto-sans-arabic" />
+  <link data-trunk rel="copy-file" href="../../assets/fonts/noto-sans-kr/NotoSansKR-Regular.otf" data-target-path="fonts/noto-sans-kr" />
+  <link data-trunk rel="copy-file" href="../../assets/fonts/noto-sans-kr/OFL.txt" data-target-path="fonts/noto-sans-kr" />
+  <link data-trunk rel="copy-file" href="../../assets/fonts/noto-sans-sc/NotoSansSC-Regular.otf" data-target-path="fonts/noto-sans-sc" />
+  <link data-trunk rel="copy-file" href="../../assets/fonts/noto-sans-sc/OFL.txt" data-target-path="fonts/noto-sans-sc" />
+  <link data-trunk rel="copy-file" href="../../assets/fonts/noto-sans-tc/NotoSansTC-Regular.otf" data-target-path="fonts/noto-sans-tc" />
+  <link data-trunk rel="copy-file" href="../../assets/fonts/noto-sans-tc/OFL.txt" data-target-path="fonts/noto-sans-tc" />
   <link data-trunk rel="css" href="../../assets/styles/web/loading.css" />
   <link data-trunk rel="copy-file" href="../../assets/styles/web/loading-logo.svg" />
   <!-- Installable as an app (manifest.webmanifest); the icons are the Linux exports of the app mark. -->

apps/solidcraft-web/src/main.rs

@@ -23,6 +23,11 @@ mod linked;
 #[cfg(any(target_arch = "wasm32", test))]
 mod space_mouse;
 
+/// The folder the page serves its fonts from: index.html copies each there, and a drawing's text
+/// fetches its fonts from it (#4890).
+#[cfg(any(target_arch = "wasm32", test))]
+const FONTS: &str = "fonts";
+
 /// The browser switches tabs with Ctrl+Tab and Ctrl+Shift+Tab, so the page leaves those keys to
 /// it (#5227); plain Tab and Shift+Tab still move between the app's fields. (Ctrl+PageUp and
 /// Ctrl+PageDown already reach the browser.)
@@ -287,6 +292,8 @@ mod web {
     const CHINESE_TC_FONT_PATH: &str = "./fonts/CraftUI-TC.otf";
 
     type FontLoadResult = Rc<std::cell::RefCell<Option<Result<(String, Vec<u8>), String>>>>;
+    /// The fetches of drawing fonts that have finished, for the next frame to hand on.
+    type DrawingFontsDone = Rc<std::cell::RefCell<Vec<(solidcraft_engine::sketch::fallback::WebFont, Result<Vec<u8>, String>)>>>;
 
     struct Shell {
         app: SolveApp,
@@ -317,6 +324,9 @@ mod web {
         font_fetch_kind: Option<&'static str>,
         /// The language the fonts were last set up for (a CJK UI leads with the CJK face).
         font_language: String,
+        /// The fonts a drawing's text asked for, other than Japanese, each fetched once a session.
+        drawing_fonts_asked: std::collections::HashSet<solidcraft_engine::sketch::fallback::WebFont>,
+        drawing_fonts_done: DrawingFontsDone,
         space_mouse: SpaceMouse,
         wheel_gestures: solidcraft_ui_egui::WebWheelGestures,
         /// The settings this tab wrote or loaded last, and those another tab wrote since (#8644).
@@ -720,6 +730,10 @@ mod web {
                                 self.chinese_kind = Some("zh-TW");
                             }
                             _ => {
+                                solidcraft_engine::sketch::fallback::provide_web_font(
+                                    solidcraft_engine::sketch::fallback::WebFont::Japanese,
+                                    bytes.clone(),
+                                );
                                 self.cjk_bytes = Some(bytes);
                             }
                         }
@@ -733,6 +747,9 @@ mod web {
                             _ => JAPANESE_FONT_PATH,
                         };
                         log::warn!("failed to fetch script font from {path}: {err}");
+                        if !matches!(kind, Some("zh" | "zh-TW")) {
+                            solidcraft_engine::sketch::fallback::web_font_failed(solidcraft_engine::sketch::fallback::WebFont::Japanese);
+                        }
                         false
                     }
                 };
@@ -768,10 +785,12 @@ mod web {
             self.font_language = effective.to_owned();
         }
 
-        /// CJK text on screen with no Japanese font yet (an English UI showing a Japanese name):
-        /// fetch the Japanese font, so the text does not stay tofu (#720).
+        /// CJK text on screen with no Japanese font yet (an English UI showing a Japanese name), or a
+        /// drawing's text waiting for one: fetch the Japanese font, so the text does not stay tofu (#720).
         fn watch_text_for_font(&mut self, ctx: &egui::Context) {
-            if self.font.watching_text() && solidcraft_ui_egui::fonts::painted_cjk(ctx) && self.font.text_needs_font() {
+            let japanese = solidcraft_engine::sketch::fallback::web_fonts_wanted().contains(&solidcraft_engine::sketch::fallback::WebFont::Japanese);
+            let wanted = solidcraft_ui_egui::fonts::painted_cjk(ctx) || japanese;
+            if self.font.watching_text() && wanted && self.font.text_needs_font() {
                 self.fetch_font(ctx, "ja");
             }
         }
@@ -792,6 +811,33 @@ mod web {
                 ctx.request_repaint();
             });
         }
+
+        /// The other fonts a drawing's text waits for (Arabic, Chinese, Korean): each fetched once,
+        /// and handed to the text when it comes. Japanese comes with the interface's CJK font.
+        fn fetch_drawing_fonts(&mut self, ctx: &egui::Context) {
+            use solidcraft_engine::sketch::fallback::{self, WebFont};
+            for (font, res) in self.drawing_fonts_done.borrow_mut().drain(..) {
+                match res {
+                    Ok(bytes) => fallback::provide_web_font(font, bytes),
+                    Err(err) => {
+                        log::warn!("failed to fetch the drawing font {}/{}: {err}", crate::FONTS, font.file());
+                        fallback::web_font_failed(font);
+                    }
+                }
+                ctx.request_repaint();
+            }
+            for font in fallback::web_fonts_wanted() {
+                if font == WebFont::Japanese || !self.drawing_fonts_asked.insert(font) {
+                    continue;
+                }
+                let (done, ctx) = (self.drawing_fonts_done.clone(), ctx.clone());
+                wasm_bindgen_futures::spawn_local(async move {
+                    let res = fetch_font_bytes(&format!("./{}/{}", crate::FONTS, font.file())).await;
+                    done.borrow_mut().push((font, res));
+                    ctx.request_repaint();
+                });
+            }
+        }
     }
 
     impl eframe::App for Shell {
@@ -799,6 +845,7 @@ mod web {
             // First: a language another tab chose fetches its font this frame.
             self.load_other_tabs_prefs();
             self.tick_font(ctx);
+            self.fetch_drawing_fonts(ctx);
             self.app.logic(ctx);
             self.api.poll();
             self.space_mouse.logic(&mut self.app, ctx);
@@ -1022,6 +1069,8 @@ mod web {
                             chinese_kind: None,
                             font_fetch_kind: None,
                             font_language,
+                            drawing_fonts_asked: Default::default(),
+                            drawing_fonts_done: Default::default(),
                             space_mouse: SpaceMouse::default(),
                             wheel_gestures: solidcraft_ui_egui::WebWheelGestures::default(),
                             prefs_writer: crate::PrefsWriter::default(),
@@ -1187,4 +1236,20 @@ mod tests {
         assert_eq!(settings_written(key, None, None), None, "clearing all storage leaves this tab's settings");
         assert_eq!(settings_written(key, Some("rc:solidcraft.prefs"), Some("{}".into())), None, "another channel's settings are not loaded");
     }
+
+    /// Each font a drawing's text can ask for on the web is one index.html copies, from an asset
+    /// in the repository, into the folder the app fetches it from.
+    #[test]
+    fn each_drawing_font_is_copied_where_it_is_fetched() {
+        let page = include_str!("../index.html");
+        let here = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));
+        for font in solidcraft_engine::sketch::fallback::WebFont::ALL {
+            let served = format!("{FONTS}/{}", font.file());
+            let (folder, file) = served.rsplit_once('/').unwrap_or_default();
+            let copy = page.lines().find(|l| l.contains("rel=\"copy-file\"") && l.contains(&format!("/{file}\""))).unwrap_or_default();
+            assert!(copy.contains(&format!("data-target-path=\"{folder}\"")), "index.html doesn't copy {served}: {copy}");
+            let from = copy.split("href=\"").nth(1).and_then(|rest| rest.split('"').next()).unwrap_or_default();
+            assert!(here.join(from).is_file(), "{served}: no {from}");
+        }
+    }
 }

assets/README.md

@@ -22,7 +22,7 @@ assets/
   appearances/library.rs             # built-in visual presets
   materials/library.rs               # physical defaults and colours
   shaders/viewport.wgsl               # original viewport shader
-  fonts/{liberation-sans,biz-udp-gothic}/ # unmodified fonts and OFL licences
+  fonts/<family>/                    # unmodified fonts and OFL licences
   locales/{en,de,ja,ko}.json          # shared offline catalogs
   platforms/{macos,linux,windows}/    # bundle, freedesktop and WiX templates
   platforms/macos/dmg/                # disk image window: layout, dmgbuild settings, background art
@@ -79,7 +79,7 @@ The CLI still supports arbitrary PNG/ICO exports with `solidcraft-cli icon`.
 | Linux, Nix, deb/rpm, tar, Flatpak, Snap | Copy canonical hicolor images; icon name stays `io.tangencylabs.solidcraft` |
 | AppImage | Uses the Linux 256 px image and `.DirIcon` alias |
 | FreeBSD | Shares Linux hicolor images and freedesktop metadata |
-| Web | HTML/Trunk and `manifest.webmanifest` stay in `apps/solidcraft-web/`; copies Japanese font/licence to `fonts/`, uses the collected CSS, and copies the Linux 32/256/512 px images to `icons/` for the favicon and installed app |
+| Web | HTML/Trunk and `manifest.webmanifest` stay in `apps/solidcraft-web/`; copies the Japanese font/licence to `fonts/` and the Noto Sans Arabic, KR, SC and TC fonts with their licences to `fonts/<family>/` (fetched when a drawing's text needs them), uses the collected CSS, and copies the Linux 32/256/512 px images to `icons/` for the favicon and installed app |
 | Docs and link previews | `xtask book` copies the shared card to the existing `/solidcraft/og.png` public path |
 
 ## Code and provenance

assets/fonts/noto-sans-arabic/OFL.txt

@@ -0,0 +1,93 @@
+Copyright 2022 The Noto Project Authors (https://github.com/notofonts/arabic)
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+https://openfontlicense.org
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

assets/fonts/noto-sans-kr/OFL.txt

@@ -0,0 +1,92 @@
+This Font Software is licensed under the SIL Open Font License,
+Version 1.1.
+
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font
+creation efforts of academic and linguistic communities, and to
+provide a free and open framework in which fonts may be shared and
+improved in partnership with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded,
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply to
+any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software
+components as distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to,
+deleting, or substituting -- in part or in whole -- any of the
+components of the Original Version, by changing formats or by porting
+the Font Software to a new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed,
+modify, redistribute, and sell modified and unmodified copies of the
+Font Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components, in
+Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the
+corresponding Copyright Holder. This restriction only applies to the
+primary font name as presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created using
+the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

assets/fonts/noto-sans-sc/OFL.txt

@@ -0,0 +1,92 @@
+This Font Software is licensed under the SIL Open Font License,
+Version 1.1.
+
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font
+creation efforts of academic and linguistic communities, and to
+provide a free and open framework in which fonts may be shared and
+improved in partnership with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded,
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply to
+any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software
+components as distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to,
+deleting, or substituting -- in part or in whole -- any of the
+components of the Original Version, by changing formats or by porting
+the Font Software to a new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed,
+modify, redistribute, and sell modified and unmodified copies of the
+Font Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components, in
+Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the
+corresponding Copyright Holder. This restriction only applies to the
+primary font name as presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created using
+the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

assets/fonts/noto-sans-tc/OFL.txt

@@ -0,0 +1,92 @@
+This Font Software is licensed under the SIL Open Font License,
+Version 1.1.
+
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font
+creation efforts of academic and linguistic communities, and to
+provide a free and open framework in which fonts may be shared and
+improved in partnership with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded,
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply to
+any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software
+components as distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to,
+deleting, or substituting -- in part or in whole -- any of the
+components of the Original Version, by changing formats or by porting
+the Font Software to a new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed,
+modify, redistribute, and sell modified and unmodified copies of the
+Font Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components, in
+Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the
+corresponding Copyright Holder. This restriction only applies to the
+primary font name as presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created using
+the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

assets/icons/ui/design/requested_icons.txt

@@ -178,6 +178,7 @@ pattern_rect	false
 perforate	false
 perspective	false
 pipe	false
+placeholder	true
 plane	false
 plane_along_path	false
 plane_angle	false

assets/icons/ui/design/svg/model/drawing_align_annotations.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Align drawing annotations</title>
+  <path d="M12 6L12 58" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M22.5 12L51.5 12A2.5 2.5 0 0 1 54 14.5L54 17.5A2.5 2.5 0 0 1 51.5 20L22.5 20A2.5 2.5 0 0 1 20 17.5L20 14.5A2.5 2.5 0 0 1 22.5 12Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M22.5 28L40.5 28A2.5 2.5 0 0 1 43 30.5L43 33.5A2.5 2.5 0 0 1 40.5 36L22.5 36A2.5 2.5 0 0 1 20 33.5L20 30.5A2.5 2.5 0 0 1 22.5 28Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M22.5 44L47.5 44A2.5 2.5 0 0 1 50 46.5L50 49.5A2.5 2.5 0 0 1 47.5 52L22.5 52A2.5 2.5 0 0 1 20 49.5L20 46.5A2.5 2.5 0 0 1 22.5 44Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_align_views.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Align drawing views</title>
+  <path d="M10.5 24L23.5 24A2.5 2.5 0 0 1 26 26.5L26 43.5A2.5 2.5 0 0 1 23.5 46L10.5 46A2.5 2.5 0 0 1 8 43.5L8 26.5A2.5 2.5 0 0 1 10.5 24Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M39.5 12L52.5 12A2.5 2.5 0 0 1 55 14.5L55 43.5A2.5 2.5 0 0 1 52.5 46L39.5 46A2.5 2.5 0 0 1 37 43.5L37 14.5A2.5 2.5 0 0 1 39.5 12Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M6 52L58 52" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M17 29L17 40M46 18L46 39" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_balloon.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Drawing balloon</title>
+  <path d="M9.5 37L29.5 37A2.5 2.5 0 0 1 32 39.5L32 52.5A2.5 2.5 0 0 1 29.5 55L9.5 55A2.5 2.5 0 0 1 7 52.5L7 39.5A2.5 2.5 0 0 1 9.5 37Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M20 45L35 30L40 25" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M15 50L19 37L28 45Z" fill="#236ead"/>
+  <circle cx="45" cy="17" r="12" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_base_view.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Base drawing view</title>
+  <path d="M9.5 10L54.5 10A2.5 2.5 0 0 1 57 12.5L57 51.5A2.5 2.5 0 0 1 54.5 54L9.5 54A2.5 2.5 0 0 1 7 51.5L7 12.5A2.5 2.5 0 0 1 9.5 10Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M17.5 19L42.5 19A2.5 2.5 0 0 1 45 21.5L45 39.5A2.5 2.5 0 0 1 42.5 42L17.5 42A2.5 2.5 0 0 1 15 39.5L15 21.5A2.5 2.5 0 0 1 17.5 19Z" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="30" cy="30.5" r="6" fill="none" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M47 46L53 46M50 43L50 49" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_centre_mark.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Drawing centre mark</title>
+  <circle cx="32" cy="32" r="18" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M32 6L32 21M32 27L32 37M32 43L32 58M6 32L21 32M27 32L37 32M43 32L58 32" fill="none" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_check.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Check drawing</title>
+  <path d="M14.5 7L49.5 7A2.5 2.5 0 0 1 52 9.5L52 54.5A2.5 2.5 0 0 1 49.5 57L14.5 57A2.5 2.5 0 0 1 12 54.5L12 9.5A2.5 2.5 0 0 1 14.5 7Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M21 19L42 19M21 29L35 29" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M27 44L37 53L57 30" fill="none" stroke="#ffffff" stroke-width="6.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M27 44L37 53L57 30" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_datum.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Drawing datum</title>
+  <path d="M6 53L58 53" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M32 52L24 38L40 38Z" fill="#236ead"/>
+  <path d="M32 38L32 27" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M21.5 7L42.5 7A2.5 2.5 0 0 1 45 9.5L45 24.5A2.5 2.5 0 0 1 42.5 27L21.5 27A2.5 2.5 0 0 1 19 24.5L19 9.5A2.5 2.5 0 0 1 21.5 7Z" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_detail_view.svg

@@ -0,0 +1,9 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Detail drawing view</title>
+  <path d="M9.5 11L30.5 11A2.5 2.5 0 0 1 33 13.5L33 45.5A2.5 2.5 0 0 1 30.5 48L9.5 48A2.5 2.5 0 0 1 7 45.5L7 13.5A2.5 2.5 0 0 1 9.5 11Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M13 18L23 18L23 33L29 33" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="23" cy="30" r="9" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M31 35L39 41" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="47" cy="46" r="12" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M40 39L46 39L46 48L53 48" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_dimension.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Drawing dimension</title>
+  <path d="M10 10L10 55M54 10L54 55" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M10 14L54 14L54 36L10 36Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M20 49L44 49" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M11 49L23 43L23 55Z" fill="#236ead"/>
+  <path d="M53 49L41 55L41 43Z" fill="#236ead"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_edit_table.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Edit drawing table</title>
+  <path d="M10.5 10L53.5 10A2.5 2.5 0 0 1 56 12.5L56 51.5A2.5 2.5 0 0 1 53.5 54L10.5 54A2.5 2.5 0 0 1 8 51.5L8 12.5A2.5 2.5 0 0 1 10.5 10Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M10 12L54 12L54 23L10 23Z" fill="#b8c3cf"/>
+  <path d="M8 24L56 24M8 39L56 39M23 24L23 54" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M25 26L54 26L54 37L25 37Z" fill="#b9ddf8"/>
+  <path d="M32 32L47 32M42 27L47 32L42 37" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_hole_callout.svg

@@ -0,0 +1,9 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Hole callout</title>
+  <circle cx="18" cy="43" r="13" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="18" cy="43" r="6" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M27 35L39 22L57 22" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M23 40L27 28L34 35Z" fill="#236ead"/>
+  <circle cx="44" cy="10" r="4.5" fill="none" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M39 16L49 4" fill="none" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_image.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Insert drawing image</title>
+  <path d="M9.5 11L54.5 11A2.5 2.5 0 0 1 57 13.5L57 50.5A2.5 2.5 0 0 1 54.5 53L9.5 53A2.5 2.5 0 0 1 7 50.5L7 13.5A2.5 2.5 0 0 1 9.5 11Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="43" cy="23" r="5" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M10 45L24 27L36 41L42 34L54 47Z" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_leader.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Drawing leader</title>
+  <path d="M8.5 34L33.5 34A2.5 2.5 0 0 1 36 36.5L36 51.5A2.5 2.5 0 0 1 33.5 54L8.5 54A2.5 2.5 0 0 1 6 51.5L6 36.5A2.5 2.5 0 0 1 8.5 34Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M18 45L39 18L56 18" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M15 49L19 35L26 41Z" fill="#236ead"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_parts_list.svg

@@ -0,0 +1,9 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Drawing parts list</title>
+  <path d="M10.5 10L53.5 10A2.5 2.5 0 0 1 56 12.5L56 51.5A2.5 2.5 0 0 1 53.5 54L10.5 54A2.5 2.5 0 0 1 8 51.5L8 12.5A2.5 2.5 0 0 1 10.5 10Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M10 12L54 12L54 23L10 23Z" fill="#b8c3cf"/>
+  <path d="M8 24L56 24M8 39L56 39M23 24L23 54" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="15.5" cy="31.5" r="3.5" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="15.5" cy="46.5" r="3.5" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M30 31L48 31M30 46L48 46" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_print.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Print drawing</title>
+  <path d="M18.5 7L45.5 7A2.5 2.5 0 0 1 48 9.5L48 29.5A2.5 2.5 0 0 1 45.5 32L18.5 32A2.5 2.5 0 0 1 16 29.5L16 9.5A2.5 2.5 0 0 1 18.5 7Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M8.5 24L55.5 24A2.5 2.5 0 0 1 58 26.5L58 49.5A2.5 2.5 0 0 1 55.5 52L8.5 52A2.5 2.5 0 0 1 6 49.5L6 26.5A2.5 2.5 0 0 1 8.5 24Z" fill="#b8c3cf" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="48" cy="32" r="2.5" fill="#236ead" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M18.5 37L45.5 37A2.5 2.5 0 0 1 48 39.5L48 55.5A2.5 2.5 0 0 1 45.5 58L18.5 58A2.5 2.5 0 0 1 16 55.5L16 39.5A2.5 2.5 0 0 1 18.5 37Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M23 44L41 44M23 51L36 51" fill="none" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_projected_view.svg

@@ -0,0 +1,9 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Projected drawing view</title>
+  <path d="M9.5 33L31.5 33A2.5 2.5 0 0 1 34 35.5L34 52.5A2.5 2.5 0 0 1 31.5 55L9.5 55A2.5 2.5 0 0 1 7 52.5L7 35.5A2.5 2.5 0 0 1 9.5 33Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <circle cx="20.5" cy="44" r="5" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M9.5 8L31.5 8A2.5 2.5 0 0 1 34 10.5L34 19.5A2.5 2.5 0 0 1 31.5 22L9.5 22A2.5 2.5 0 0 1 7 19.5L7 10.5A2.5 2.5 0 0 1 9.5 8Z" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M9 25L9 30M32 25L32 30M38 44L54 44" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round" stroke-dasharray="3 5"/>
+  <path d="M44 28L44 13" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M44 7L48 14L40 14Z" fill="#236ead"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_resources.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Browse drawing resources</title>
+  <path d="M15 7L51 7A3 3 0 0 1 54 10L54 48A3 3 0 0 1 51 51L15 51A3 3 0 0 1 12 48L12 10A3 3 0 0 1 15 7Z" fill="#b8c3cf" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M10 12L46 12A3 3 0 0 1 49 15L49 53A3 3 0 0 1 46 56L10 56A3 3 0 0 1 7 53L7 15A3 3 0 0 1 10 12Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M14 20L42 20L42 47L14 47Z" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M14 38L42 38M28 38L28 47" fill="none" stroke="#6f879c" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M22 27L34 27L34 36L22 36Z" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_revision.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Add drawing revision</title>
+  <path d="M14.5 7L49.5 7A2.5 2.5 0 0 1 52 9.5L52 54.5A2.5 2.5 0 0 1 49.5 57L14.5 57A2.5 2.5 0 0 1 12 54.5L12 9.5A2.5 2.5 0 0 1 14.5 7Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M20 19L43 19M20 29L37 29" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M43 33L58 57L28 57Z" fill="#ffffff" stroke="#ffffff" stroke-width="4.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M43 33L58 57L28 57Z" fill="#b9ddf8" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_revision_table.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Drawing revision table</title>
+  <path d="M10.5 10L53.5 10A2.5 2.5 0 0 1 56 12.5L56 51.5A2.5 2.5 0 0 1 53.5 54L10.5 54A2.5 2.5 0 0 1 8 51.5L8 12.5A2.5 2.5 0 0 1 10.5 10Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M10 12L54 12L54 23L10 23Z" fill="#b8c3cf"/>
+  <path d="M8 24L56 24M8 39L56 39M23 24L23 54" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M15 27L10 35L20 35ZM15 42L10 50L20 50Z" fill="#236ead"/>
+  <path d="M31 31L49 31M31 46L49 46" fill="none" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_section_view.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Section drawing view</title>
+  <path d="M8 15L56 15L56 50L37 50L37 27L27 27L27 50L8 50Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M10 38L26 22M10 25L20 15M10 50L24 36M39 35L54 20M39 48L54 33M49 50L56 43" fill="none" stroke="#236ead" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_space_annotations.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Space drawing annotations</title>
+  <path d="M28.5 9L53.5 9A2.5 2.5 0 0 1 56 11.5L56 14.5A2.5 2.5 0 0 1 53.5 17L28.5 17A2.5 2.5 0 0 1 26 14.5L26 11.5A2.5 2.5 0 0 1 28.5 9Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M28.5 28L53.5 28A2.5 2.5 0 0 1 56 30.5L56 33.5A2.5 2.5 0 0 1 53.5 36L28.5 36A2.5 2.5 0 0 1 26 33.5L26 30.5A2.5 2.5 0 0 1 28.5 28Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M28.5 47L53.5 47A2.5 2.5 0 0 1 56 49.5L56 52.5A2.5 2.5 0 0 1 53.5 55L28.5 55A2.5 2.5 0 0 1 26 52.5L26 49.5A2.5 2.5 0 0 1 28.5 47Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M15 19L15 25M15 38L15 44" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M15 14L10 21L20 21ZM15 30L10 23L20 23ZM15 33L10 40L20 40ZM15 49L10 42L20 42Z" fill="#236ead"/>
+</svg>

assets/icons/ui/design/svg/model/drawing_update.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <title>Update drawing</title>
+  <path d="M14.5 7L49.5 7A2.5 2.5 0 0 1 52 9.5L52 54.5A2.5 2.5 0 0 1 49.5 57L14.5 57A2.5 2.5 0 0 1 12 54.5L12 9.5A2.5 2.5 0 0 1 14.5 7Z" fill="#e2e8ef" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M22.5 16L41.5 16A2.5 2.5 0 0 1 44 18.5L44 28.5A2.5 2.5 0 0 1 41.5 31L22.5 31A2.5 2.5 0 0 1 20 28.5L20 18.5A2.5 2.5 0 0 1 22.5 16Z" fill="#b8c3cf" stroke="#34465b" stroke-width="2.55" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M38 35A11 11 0 1 0 45 45" fill="none" stroke="#ffffff" stroke-width="6.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M38 35A11 11 0 1 0 45 45" fill="none" stroke="#236ead" stroke-width="4.25" stroke-linejoin="round" stroke-linecap="round"/>
+  <path d="M44 40L32 37L40 28Z" fill="#236ead"/>
+</svg>

assets/locales/de.json

@@ -833,6 +833,8 @@
   "cmd.appearance_pick_up": "Aussehen aufnehmen",
   "cmd.appearance_replace": "Erscheinungsbild ersetzen",
   "cmd.assembly_bom": "Stückliste",
+  "cmd.assembly_bom_item_set": "Positionsnummer ändern",
+  "cmd.assembly_bom_renumber": "Positionen neu nummerieren",
   "cmd.assembly_mass_properties": "Masseeigenschaften",
   "cmd.body.print_face": "Auflagefläche",
   "cmd.body_rename": "Körper umbenennen",
@@ -1024,6 +1026,7 @@
   "cmd.motion_trace_edit": "Bewegungsbahn bearbeiten",
   "cmd.motion_trace_keep": "Bewegungsbahn behalten",
   "cmd.occurrence_align": "Instanz ausrichten",
+  "cmd.occurrence_bom_type": "Stücklistentyp",
   "cmd.occurrence_copy": "Einfügen (Instanz)",
   "cmd.occurrence_drag": "Instanz ziehen",
   "cmd.occurrence_ground": "Festsetzen",
@@ -2327,6 +2330,7 @@
   "prefs.dimension_values_view": "In der Ansicht",
   "prefs.dimension_values_window": "In einem Fenster",
   "prefs.display": "Anzeige",
+  "prefs.drawings": "Zeichnungen",
   "prefs.edges": "Kanten und Schattierung",
   "prefs.extend": "Erweitern",
   "prefs.extra_navigation": "Mit Strg und gedrückter linker Maustaste auf einer freien Fläche drehen. Leertaste gedrückt halten, um die Ansicht zu verschieben.",
@@ -4953,6 +4957,7 @@
   "ui.fine": "Fein",
   "ui.finest": "Sehr fein",
   "ui.finish_sketch": "Skizze beenden",
+  "ui.first_angle": "Erster Winkel",
   "ui.fit": "Einpassen",
   "ui.fix_unfix": "Fixieren/Lösen",
   "ui.flat": "Flach",
@@ -5253,6 +5258,7 @@
   "ui.profiles": "Profile",
   "ui.project": "Projizieren",
   "ui.project_face_edges_sketch": "Flächenkanten in neue Skizzen projizieren",
+  "ui.projection_of_new_drawings": "Projektion neuer Zeichnungen",
   "ui.properties": "Eigenschaften",
   "ui.properties.copy_matrix": "Matrix kopieren",
   "ui.properties.first_moments": "Statische Momente",
@@ -5435,6 +5441,7 @@
   "ui.text": "Text",
   "ui.theme": "Design",
   "ui.thickness": "Dicke",
+  "ui.third_angle": "Dritter Winkel",
   "ui.thread": "Gewinde",
   "ui.tie_ends": "Verknüpfen",
   "ui.tie_ends_tip": "Alle unverknüpften Enden mit Abhängigkeiten versehen",

assets/locales/en.json

@@ -833,6 +833,8 @@
   "cmd.appearance_pick_up": "Pick Up Appearance",
   "cmd.appearance_replace": "Replace Appearance",
   "cmd.assembly_bom": "Bill of Materials",
+  "cmd.assembly_bom_item_set": "Change Item Number",
+  "cmd.assembly_bom_renumber": "Renumber Items",
   "cmd.assembly_mass_properties": "Mass Properties",
   "cmd.body.print_face": "Print Face",
   "cmd.body_rename": "Rename Body",
@@ -932,6 +934,36 @@
   "cmd.document_metadata_set": "Change Design Properties",
   "cmd.document_revision": "Design Revision",
   "cmd.document_units": "Change Design Units",
+  "cmd.drawing_balloon_add": "Add Balloon",
+  "cmd.drawing_balloon_edit": "Edit Balloon",
+  "cmd.drawing_balloon_inspect": "Inspect Balloon",
+  "cmd.drawing_close": "Close Drawing",
+  "cmd.drawing_create": "Create Drawing",
+  "cmd.drawing_delete": "Delete Drawing",
+  "cmd.drawing_dimension_add": "Add Drawing Dimension",
+  "cmd.drawing_dimension_edit": "Edit Drawing Dimension",
+  "cmd.drawing_dimension_inspect": "Inspect Drawing Dimension",
+  "cmd.drawing_export": "Export Sheet",
+  "cmd.drawing_inspect": "Inspect Drawing",
+  "cmd.drawing_list": "List Drawings",
+  "cmd.drawing_open": "Open Drawing",
+  "cmd.drawing_properties": "Drawing Properties",
+  "cmd.drawing_properties_remove": "Remove Drawing Property",
+  "cmd.drawing_properties_set": "Change Drawing Properties",
+  "cmd.drawing_revision_add": "Add Revision",
+  "cmd.drawing_revision_delete": "Delete Revision",
+  "cmd.drawing_revision_edit": "Edit Revision",
+  "cmd.drawing_scene": "Draw Sheet",
+  "cmd.drawing_set": "Drawing Settings",
+  "cmd.drawing_sheet_add": "Add Sheet",
+  "cmd.drawing_sheet_delete": "Delete Sheet",
+  "cmd.drawing_sheet_reorder": "Reorder Sheets",
+  "cmd.drawing_sheet_set": "Sheet Settings",
+  "cmd.drawing_view_copy_to_sheet": "Copy View to Sheet",
+  "cmd.drawing_view_edit": "Edit Drawing View",
+  "cmd.drawing_view_inspect": "Inspect Drawing View",
+  "cmd.drawing_view_move_to_sheet": "Move View to Sheet",
+  "cmd.drawing_view_snapshot": "Drawing View Snapshot",
   "cmd.edit_checkpoint": "Checkpoint",
   "cmd.edit_repeat": "Repeat Last Command",
   "cmd.edit_restore_checkpoint": "Restore Checkpoint",
@@ -1029,6 +1061,7 @@
   "cmd.motion_trace_edit": "Edit Motion Trace",
   "cmd.motion_trace_keep": "Keep Motion Trace",
   "cmd.occurrence_align": "Align Occurrence",
+  "cmd.occurrence_bom_type": "Bill of Materials Type",
   "cmd.occurrence_copy": "Paste (Instance)",
   "cmd.occurrence_drag": "Drag Occurrence",
   "cmd.occurrence_ground": "Ground",
@@ -2345,6 +2378,7 @@
   "prefs.dimension_values_view": "In the view",
   "prefs.dimension_values_window": "In a window",
   "prefs.display": "Display",
+  "prefs.drawings": "Drawings",
   "prefs.edges": "Edges and shading",
   "prefs.extend": "Extend",
   "prefs.extra_navigation": "Ctrl+left drag on empty space orbits; hold Space to pan.",
@@ -4981,6 +5015,7 @@
   "ui.fine": "Fine",
   "ui.finest": "Finest",
   "ui.finish_sketch": "Finish Sketch",
+  "ui.first_angle": "First angle",
   "ui.fit": "Fit",
   "ui.fix_unfix": "Fix/Unfix",
   "ui.flat": "Flat",
@@ -5285,6 +5320,7 @@
   "ui.profiles": "Profiles",
   "ui.project": "Project",
   "ui.project_face_edges_sketch": "Project face edges into new sketches",
+  "ui.projection_of_new_drawings": "Projection of new drawings",
   "ui.properties": "Properties",
   "ui.properties.copy_matrix": "Copy matrix",
   "ui.properties.first_moments": "First moments",
@@ -5470,6 +5506,7 @@
   "ui.text": "Text",
   "ui.theme": "Theme",
   "ui.thickness": "Thickness",
+  "ui.third_angle": "Third angle",
   "ui.thread": "Thread",
   "ui.tie_ends": "Tie",
   "ui.tie_ends_tip": "Constrain all untied ends",

assets/locales/ja.json

@@ -833,6 +833,8 @@
   "cmd.appearance_pick_up": "外観を取得",
   "cmd.appearance_replace": "外観を置換",
   "cmd.assembly_bom": "部品表",
+  "cmd.assembly_bom_item_set": "項目番号の変更",
+  "cmd.assembly_bom_renumber": "項目番号の振り直し",
   "cmd.assembly_mass_properties": "質量特性",
   "cmd.body.print_face": "造形面",
   "cmd.body_rename": "ボディの名前を変更",
@@ -932,6 +934,36 @@
   "cmd.document_metadata_set": "デザインのプロパティを変更",
   "cmd.document_revision": "デザイン リビジョン",
   "cmd.document_units": "デザインの単位を変更",
+  "cmd.drawing_balloon_add": "バルーンを追加",
+  "cmd.drawing_balloon_edit": "バルーンを編集",
+  "cmd.drawing_balloon_inspect": "バルーンを確認",
+  "cmd.drawing_close": "図面を閉じる",
+  "cmd.drawing_create": "図面を作成",
+  "cmd.drawing_delete": "図面を削除",
+  "cmd.drawing_dimension_add": "図面寸法を追加",
+  "cmd.drawing_dimension_edit": "図面寸法を編集",
+  "cmd.drawing_dimension_inspect": "図面寸法を確認",
+  "cmd.drawing_export": "シートを書き出す",
+  "cmd.drawing_inspect": "図面を確認",
+  "cmd.drawing_list": "図面を一覧表示",
+  "cmd.drawing_open": "図面を開く",
+  "cmd.drawing_properties": "図面のプロパティ",
+  "cmd.drawing_properties_remove": "図面のプロパティを削除",
+  "cmd.drawing_properties_set": "図面のプロパティを変更",
+  "cmd.drawing_revision_add": "リビジョンを追加",
+  "cmd.drawing_revision_delete": "リビジョンを削除",
+  "cmd.drawing_revision_edit": "リビジョンを編集",
+  "cmd.drawing_scene": "シートを描画",
+  "cmd.drawing_set": "図面設定",
+  "cmd.drawing_sheet_add": "シートを追加",
+  "cmd.drawing_sheet_delete": "シートを削除",
+  "cmd.drawing_sheet_reorder": "シートを並べ替え",
+  "cmd.drawing_sheet_set": "シート設定",
+  "cmd.drawing_view_copy_to_sheet": "ビューをシートにコピー",
+  "cmd.drawing_view_edit": "図面ビューを編集",
+  "cmd.drawing_view_inspect": "図面ビューを確認",
+  "cmd.drawing_view_move_to_sheet": "ビューをシートに移動",
+  "cmd.drawing_view_snapshot": "図面ビューのスナップショット",
   "cmd.edit_checkpoint": "チェックポイント",
   "cmd.edit_repeat": "最後のコマンドを繰り返す",
   "cmd.edit_restore_checkpoint": "チェックポイントを復元",
@@ -1029,6 +1061,7 @@
   "cmd.motion_trace_edit": "モーション トレースを編集",
   "cmd.motion_trace_keep": "モーション トレースを保持",
   "cmd.occurrence_align": "オカレンスを整列",
+  "cmd.occurrence_bom_type": "部品表の種類",
   "cmd.occurrence_copy": "貼り付け（インスタンス）",
   "cmd.occurrence_drag": "オカレンスをドラッグ",
   "cmd.occurrence_ground": "空間固定",
@@ -2345,6 +2378,7 @@
   "prefs.dimension_values_view": "ビュー内",
   "prefs.dimension_values_window": "ウィンドウ",
   "prefs.display": "表示",
+  "prefs.drawings": "図面",
   "prefs.edges": "エッジと陰影",
   "prefs.extend": "拡張",
   "prefs.extra_navigation": "何もない場所でCtrl＋左ドラッグすると回転し、Spaceを押しながらドラッグすると移動します。",
@@ -4981,6 +5015,7 @@
   "ui.fine": "細かい",
   "ui.finest": "最も細かい",
   "ui.finish_sketch": "スケッチを終了",
+  "ui.first_angle": "第一角法",
   "ui.fit": "フィット",
   "ui.fix_unfix": "固定/固定解除",
   "ui.flat": "展開",
@@ -5285,6 +5320,7 @@
   "ui.profiles": "プロファイル",
   "ui.project": "投影",
   "ui.project_face_edges_sketch": "新規スケッチに面のエッジを自動投影",
+  "ui.projection_of_new_drawings": "新規図面の投影法",
   "ui.properties": "プロパティ",
   "ui.properties.copy_matrix": "行列をコピー",
   "ui.properties.first_moments": "一次モーメント",
@@ -5470,6 +5506,7 @@
   "ui.text": "テキスト",
   "ui.theme": "テーマ",
   "ui.thickness": "厚さ",
+  "ui.third_angle": "第三角法",
   "ui.thread": "ねじ",
   "ui.tie_ends": "拘束",
   "ui.tie_ends_tip": "未拘束をすべて拘束",

assets/locales/ko.json

@@ -724,6 +724,8 @@
   "cmd.appearance_pick_up": "모양 가져오기",
   "cmd.appearance_replace": "모양 바꾸기",
   "cmd.assembly_bom": "자재 명세서",
+  "cmd.assembly_bom_item_set": "항목 번호 변경",
+  "cmd.assembly_bom_renumber": "항목 번호 다시 매기기",
   "cmd.assembly_mass_properties": "질량 특성",
   "cmd.body.print_face": "출력 바닥면",
   "cmd.body_rename": "바디 이름 변경",
@@ -894,6 +896,7 @@
   "cmd.motion_study": "운동 연구",
   "cmd.motion_trace": "모션 궤적",
   "cmd.motion_trace_keep": "모션 궤적 유지",
+  "cmd.occurrence_bom_type": "자재 명세서 유형",
   "cmd.occurrence_copy": "붙여넣기(인스턴스)",
   "cmd.occurrence_ground": "고정",
   "cmd.occurrence_move": "인스턴스 이동",
@@ -1732,6 +1735,7 @@
   "prefs.dimension_values_view": "뷰에서",
   "prefs.dimension_values_window": "창에서",
   "prefs.display": "표시",
+  "prefs.drawings": "도면",
   "prefs.edges": "모서리 및 음영",
   "prefs.extend": "확장",
   "prefs.extra_navigation": "Ctrl+왼쪽 드래그로 빈 공간에서 회전하고, Space를 누른 채 이동합니다.",
@@ -3750,6 +3754,7 @@
   "ui.fine": "세밀",
   "ui.finest": "가장 세밀",
   "ui.finish_sketch": "스케치 종료",
+  "ui.first_angle": "제1각법",
   "ui.fit": "맞춤",
   "ui.fix_unfix": "고정/고정 해제",
   "ui.flat": "플랫",
@@ -4023,6 +4028,7 @@
   "ui.profiles": "프로파일",
   "ui.project": "투영",
   "ui.project_face_edges_sketch": "면 모서리를 새 스케치로 투영",
+  "ui.projection_of_new_drawings": "새 도면의 투상법",
   "ui.properties": "속성",
   "ui.properties.copy_matrix": "행렬 복사",
   "ui.properties.first_moments": "1차 모멘트",
@@ -4182,6 +4188,7 @@
   "ui.text": "텍스트",
   "ui.theme": "테마",
   "ui.thickness": "두께",
+  "ui.third_angle": "제3각법",
   "ui.thread": "나사산",
   "ui.tie_ends": "연결",
   "ui.tie_ends_tip": "연결되지 않은 모든 끝점 구속",

assets/locales/pending/drawing-export-paper.json

@@ -0,0 +1,34 @@
+{
+  "en": {
+    "export.paper.blueprint": "Blueprint Blue",
+    "export.paper.prussian_blue": "Prussian Blue (Historical)"
+  },
+  "ar": {
+    "export.paper.blueprint": "أزرق المخطط",
+    "export.paper.prussian_blue": "أزرق بروسي (تاريخي)"
+  },
+  "de": {
+    "export.paper.blueprint": "Blaupausenblau",
+    "export.paper.prussian_blue": "Preußischblau (historisch)"
+  },
+  "he": {
+    "export.paper.blueprint": "כחול שרטוט",
+    "export.paper.prussian_blue": "כחול פרוסי (היסטורי)"
+  },
+  "ja": {
+    "export.paper.blueprint": "ブループリントブルー",
+    "export.paper.prussian_blue": "プルシアンブルー（歴史的）"
+  },
+  "ko": {
+    "export.paper.blueprint": "블루프린트 블루",
+    "export.paper.prussian_blue": "프러시안 블루(역사적)"
+  },
+  "vi": {
+    "export.paper.blueprint": "Xanh bản vẽ",
+    "export.paper.prussian_blue": "Xanh Phổ (lịch sử)"
+  },
+  "zh": {
+    "export.paper.blueprint": "蓝图蓝",
+    "export.paper.prussian_blue": "普鲁士蓝（历史）"
+  }
+}

assets/locales/pending/drawing-image.json

@@ -0,0 +1,26 @@
+{
+  "en": {
+    "cmd.drawing_image_add": "Add Image"
+  },
+  "ar": {
+    "cmd.drawing_image_add": "إضافة صورة"
+  },
+  "de": {
+    "cmd.drawing_image_add": "Bild hinzufügen"
+  },
+  "he": {
+    "cmd.drawing_image_add": "הוספת תמונה"
+  },
+  "ja": {
+    "cmd.drawing_image_add": "画像を追加"
+  },
+  "ko": {
+    "cmd.drawing_image_add": "이미지 추가"
+  },
+  "vi": {
+    "cmd.drawing_image_add": "Thêm hình ảnh"
+  },
+  "zh": {
+    "cmd.drawing_image_add": "添加图像"
+  }
+}

assets/locales/pending/drawing-notes.json

@@ -0,0 +1,42 @@
+{
+  "en": {
+    "cmd.drawing_note_add": "Add Note",
+    "cmd.drawing_note_edit": "Edit Note",
+    "cmd.drawing_note_inspect": "Inspect Note"
+  },
+  "ar": {
+    "cmd.drawing_note_add": "إضافة ملاحظة",
+    "cmd.drawing_note_edit": "تحرير الملاحظة",
+    "cmd.drawing_note_inspect": "فحص الملاحظة"
+  },
+  "de": {
+    "cmd.drawing_note_add": "Hinweis hinzufügen",
+    "cmd.drawing_note_edit": "Hinweis bearbeiten",
+    "cmd.drawing_note_inspect": "Hinweis prüfen"
+  },
+  "he": {
+    "cmd.drawing_note_add": "הוספת הערה",
+    "cmd.drawing_note_edit": "עריכת הערה",
+    "cmd.drawing_note_inspect": "בדיקת הערה"
+  },
+  "ja": {
+    "cmd.drawing_note_add": "注記を追加",
+    "cmd.drawing_note_edit": "注記を編集",
+    "cmd.drawing_note_inspect": "注記を確認"
+  },
+  "ko": {
+    "cmd.drawing_note_add": "주석 추가",
+    "cmd.drawing_note_edit": "주석 편집",
+    "cmd.drawing_note_inspect": "주석 확인"
+  },
+  "vi": {
+    "cmd.drawing_note_add": "Thêm ghi chú",
+    "cmd.drawing_note_edit": "Sửa ghi chú",
+    "cmd.drawing_note_inspect": "Kiểm tra ghi chú"
+  },
+  "zh": {
+    "cmd.drawing_note_add": "添加注释",
+    "cmd.drawing_note_edit": "编辑注释",
+    "cmd.drawing_note_inspect": "检查注释"
+  }
+}

assets/locales/pending/drawing-repair.json

@@ -0,0 +1,34 @@
+{
+  "en": {
+    "cmd.drawing_balloon_repair": "Repair Balloon",
+    "cmd.drawing_dimension_repair": "Repair Drawing Dimension"
+  },
+  "ar": {
+    "cmd.drawing_balloon_repair": "إصلاح البالون",
+    "cmd.drawing_dimension_repair": "إصلاح بُعد اللوحة"
+  },
+  "de": {
+    "cmd.drawing_balloon_repair": "Positionsnummer reparieren",
+    "cmd.drawing_dimension_repair": "Zeichnungsbemaßung reparieren"
+  },
+  "he": {
+    "cmd.drawing_balloon_repair": "תיקון בלון",
+    "cmd.drawing_dimension_repair": "תיקון מידת שרטוט"
+  },
+  "ja": {
+    "cmd.drawing_balloon_repair": "バルーンを修復",
+    "cmd.drawing_dimension_repair": "図面寸法を修復"
+  },
+  "ko": {
+    "cmd.drawing_balloon_repair": "벌룬 복구",
+    "cmd.drawing_dimension_repair": "도면 치수 복구"
+  },
+  "vi": {
+    "cmd.drawing_balloon_repair": "Sửa chữa bóng chú thích",
+    "cmd.drawing_dimension_repair": "Sửa chữa kích thước bản vẽ"
+  },
+  "zh": {
+    "cmd.drawing_balloon_repair": "修复零件序号",
+    "cmd.drawing_dimension_repair": "修复绘图尺寸"
+  }
+}

assets/locales/pending/drawing-revise.json

@@ -0,0 +1,26 @@
+{
+  "en": {
+    "cmd.drawing_revise": "Issue Revision"
+  },
+  "ar": {
+    "cmd.drawing_revise": "إصدار مراجعة"
+  },
+  "de": {
+    "cmd.drawing_revise": "Revision herausgeben"
+  },
+  "he": {
+    "cmd.drawing_revise": "הוצאת גרסה"
+  },
+  "ja": {
+    "cmd.drawing_revise": "リビジョンを発行"
+  },
+  "ko": {
+    "cmd.drawing_revise": "리비전 발행"
+  },
+  "vi": {
+    "cmd.drawing_revise": "Phát hành bản sửa đổi"
+  },
+  "zh": {
+    "cmd.drawing_revise": "发布版本"
+  }
+}

assets/locales/pending/drawing-revision-tags.json

@@ -0,0 +1,42 @@
+{
+  "en": {
+    "cmd.drawing_revision_tag_add": "Add Revision Tag",
+    "cmd.drawing_revision_tag_edit": "Edit Revision Tag",
+    "cmd.drawing_revision_tag_delete": "Delete Revision Tag"
+  },
+  "ar": {
+    "cmd.drawing_revision_tag_add": "إضافة علامة مراجعة",
+    "cmd.drawing_revision_tag_edit": "تحرير علامة المراجعة",
+    "cmd.drawing_revision_tag_delete": "حذف علامة المراجعة"
+  },
+  "de": {
+    "cmd.drawing_revision_tag_add": "Revisionskennzeichen hinzufügen",
+    "cmd.drawing_revision_tag_edit": "Revisionskennzeichen bearbeiten",
+    "cmd.drawing_revision_tag_delete": "Revisionskennzeichen löschen"
+  },
+  "he": {
+    "cmd.drawing_revision_tag_add": "הוספת תג גרסה",
+    "cmd.drawing_revision_tag_edit": "עריכת תג גרסה",
+    "cmd.drawing_revision_tag_delete": "מחיקת תג גרסה"
+  },
+  "ja": {
+    "cmd.drawing_revision_tag_add": "リビジョンタグを追加",
+    "cmd.drawing_revision_tag_edit": "リビジョンタグを編集",
+    "cmd.drawing_revision_tag_delete": "リビジョンタグを削除"
+  },
+  "ko": {
+    "cmd.drawing_revision_tag_add": "리비전 태그 추가",
+    "cmd.drawing_revision_tag_edit": "리비전 태그 편집",
+    "cmd.drawing_revision_tag_delete": "리비전 태그 삭제"
+  },
+  "vi": {
+    "cmd.drawing_revision_tag_add": "Thêm thẻ sửa đổi",
+    "cmd.drawing_revision_tag_edit": "Sửa thẻ sửa đổi",
+    "cmd.drawing_revision_tag_delete": "Xóa thẻ sửa đổi"
+  },
+  "zh": {
+    "cmd.drawing_revision_tag_add": "添加版本标记",
+    "cmd.drawing_revision_tag_edit": "编辑版本标记",
+    "cmd.drawing_revision_tag_delete": "删除版本标记"
+  }
+}

assets/locales/pending/drawing-status.json

@@ -0,0 +1,26 @@
+{
+  "en": {
+    "cmd.drawing_status": "Drawing Status"
+  },
+  "ar": {
+    "cmd.drawing_status": "حالة الرسم"
+  },
+  "de": {
+    "cmd.drawing_status": "Zeichnungsstatus"
+  },
+  "he": {
+    "cmd.drawing_status": "מצב השרטוט"
+  },
+  "ja": {
+    "cmd.drawing_status": "図面の状態"
+  },
+  "ko": {
+    "cmd.drawing_status": "도면 상태"
+  },
+  "vi": {
+    "cmd.drawing_status": "Trạng thái bản vẽ"
+  },
+  "zh": {
+    "cmd.drawing_status": "绘图状态"
+  }
+}

assets/locales/pending/drawing-tables.json

@@ -0,0 +1,58 @@
+{
+  "en": {
+    "cmd.drawing_table_add": "Add Table",
+    "cmd.drawing_table_delete": "Delete Table",
+    "cmd.drawing_table_edit": "Edit Table",
+    "cmd.drawing_table_inspect": "Inspect Table",
+    "help.drawing.table.edit": "Changes a saved table on a sheet: what it lists, where it sits, its columns and its words. Use it to adjust a parts list or revision table after adding it."
+  },
+  "ar": {
+    "cmd.drawing_table_add": "إضافة جدول",
+    "cmd.drawing_table_delete": "حذف الجدول",
+    "cmd.drawing_table_edit": "تحرير الجدول",
+    "cmd.drawing_table_inspect": "فحص الجدول",
+    "help.drawing.table.edit": "يغيّر جدولاً محفوظاً على ورقة: ما يعرضه ومكانه وأعمدته ونصوصه. استخدمه لضبط قائمة أجزاء أو جدول مراجعات بعد إضافته."
+  },
+  "de": {
+    "cmd.drawing_table_add": "Tabelle hinzufügen",
+    "cmd.drawing_table_delete": "Tabelle löschen",
+    "cmd.drawing_table_edit": "Tabelle bearbeiten",
+    "cmd.drawing_table_inspect": "Tabelle prüfen",
+    "help.drawing.table.edit": "Ändert eine gespeicherte Tabelle auf einem Blatt: was sie auflistet, wo sie steht, ihre Spalten und Texte. Damit passen Sie eine Stückliste oder Revisionstabelle nach dem Hinzufügen an."
+  },
+  "he": {
+    "cmd.drawing_table_add": "הוספת טבלה",
+    "cmd.drawing_table_delete": "מחיקת טבלה",
+    "cmd.drawing_table_edit": "עריכת טבלה",
+    "cmd.drawing_table_inspect": "בדיקת טבלה",
+    "help.drawing.table.edit": "משנה טבלה שמורה בגיליון: מה היא מציגה, היכן היא ממוקמת, העמודות והטקסטים שלה. השתמשו בכך כדי להתאים רשימת חלקים או טבלת גרסאות לאחר הוספתה."
+  },
+  "ja": {
+    "cmd.drawing_table_add": "表を追加",
+    "cmd.drawing_table_delete": "表を削除",
+    "cmd.drawing_table_edit": "表を編集",
+    "cmd.drawing_table_inspect": "表を確認",
+    "help.drawing.table.edit": "シート上の保存済みの表の内容、位置、列、文字を変更します。部品表や改訂表を追加した後の調整に使います。"
+  },
+  "ko": {
+    "cmd.drawing_table_add": "표 추가",
+    "cmd.drawing_table_delete": "표 삭제",
+    "cmd.drawing_table_edit": "표 편집",
+    "cmd.drawing_table_inspect": "표 확인",
+    "help.drawing.table.edit": "시트에 저장된 표의 내용, 위치, 열, 글자를 변경합니다. 부품표나 개정표를 추가한 뒤 조정할 때 사용합니다."
+  },
+  "vi": {
+    "cmd.drawing_table_add": "Thêm bảng",
+    "cmd.drawing_table_delete": "Xóa bảng",
+    "cmd.drawing_table_edit": "Sửa bảng",
+    "cmd.drawing_table_inspect": "Kiểm tra bảng",
+    "help.drawing.table.edit": "Thay đổi một bảng đã lưu trên trang: nội dung, vị trí, các cột và chữ của bảng. Dùng để chỉnh danh sách chi tiết hoặc bảng sửa đổi sau khi thêm."
+  },
+  "zh": {
+    "cmd.drawing_table_add": "添加表格",
+    "cmd.drawing_table_delete": "删除表格",
+    "cmd.drawing_table_edit": "编辑表格",
+    "cmd.drawing_table_inspect": "检查表格",
+    "help.drawing.table.edit": "更改图纸页上已保存的表格的内容、位置、列和文字。添加零件表或修订表后，可用它进行调整。"
+  }
+}

assets/locales/pending/drawing-template-apply.json

@@ -0,0 +1,26 @@
+{
+  "en": {
+    "cmd.drawing_template_apply": "Apply Drawing Template"
+  },
+  "ar": {
+    "cmd.drawing_template_apply": "تطبيق قالب لوحة"
+  },
+  "de": {
+    "cmd.drawing_template_apply": "Zeichnungsvorlage anwenden"
+  },
+  "he": {
+    "cmd.drawing_template_apply": "החלת תבנית שרטוט"
+  },
+  "ja": {
+    "cmd.drawing_template_apply": "図面テンプレートを適用"
+  },
+  "ko": {
+    "cmd.drawing_template_apply": "도면 템플릿 적용"
+  },
+  "vi": {
+    "cmd.drawing_template_apply": "Áp dụng mẫu bản vẽ"
+  },
+  "zh": {
+    "cmd.drawing_template_apply": "应用绘图模板"
+  }
+}

assets/locales/pending/drawing-template-save.json

@@ -0,0 +1,26 @@
+{
+  "en": {
+    "cmd.drawing_template_save": "Save as Drawing Template"
+  },
+  "ar": {
+    "cmd.drawing_template_save": "حفظ كقالب لوحة"
+  },
+  "de": {
+    "cmd.drawing_template_save": "Als Zeichnungsvorlage speichern"
+  },
+  "he": {
+    "cmd.drawing_template_save": "שמירה כתבנית שרטוט"
+  },
+  "ja": {
+    "cmd.drawing_template_save": "図面テンプレートとして保存"
+  },
+  "ko": {
+    "cmd.drawing_template_save": "도면 템플릿으로 저장"
+  },
+  "vi": {
+    "cmd.drawing_template_save": "Lưu thành mẫu bản vẽ"
+  },
+  "zh": {
+    "cmd.drawing_template_save": "另存为绘图模板"
+  }
+}

assets/locales/pending/drawing-templates-by-kind.json

@@ -0,0 +1,34 @@
+{
+  "en": {
+    "ui.template_for_new_part_drawings": "Template for new part drawings",
+    "ui.template_for_new_assembly_drawings": "Template for new assembly drawings"
+  },
+  "ar": {
+    "ui.template_for_new_part_drawings": "قالب لوحات القطع الجديدة",
+    "ui.template_for_new_assembly_drawings": "قالب لوحات التجميعات الجديدة"
+  },
+  "de": {
+    "ui.template_for_new_part_drawings": "Vorlage für neue Teilezeichnungen",
+    "ui.template_for_new_assembly_drawings": "Vorlage für neue Baugruppenzeichnungen"
+  },
+  "he": {
+    "ui.template_for_new_part_drawings": "תבנית לשרטוטי חלקים חדשים",
+    "ui.template_for_new_assembly_drawings": "תבנית לשרטוטי מכלולים חדשים"
+  },
+  "ja": {
+    "ui.template_for_new_part_drawings": "新しい部品図面のテンプレート",
+    "ui.template_for_new_assembly_drawings": "新しいアセンブリ図面のテンプレート"
+  },
+  "ko": {
+    "ui.template_for_new_part_drawings": "새 부품 도면의 템플릿",
+    "ui.template_for_new_assembly_drawings": "새 어셈블리 도면의 템플릿"
+  },
+  "vi": {
+    "ui.template_for_new_part_drawings": "Mẫu cho bản vẽ chi tiết mới",
+    "ui.template_for_new_assembly_drawings": "Mẫu cho bản vẽ cụm lắp ráp mới"
+  },
+  "zh": {
+    "ui.template_for_new_part_drawings": "新零件绘图的模板",
+    "ui.template_for_new_assembly_drawings": "新装配体绘图的模板"
+  }
+}

assets/locales/pending/drawing-templates-preferred.json

@@ -0,0 +1,26 @@
+{
+  "en": {
+    "cmd.drawing_template_list": "List Drawing Templates"
+  },
+  "ar": {
+    "cmd.drawing_template_list": "سرد قوالب اللوحات"
+  },
+  "de": {
+    "cmd.drawing_template_list": "Zeichnungsvorlagen auflisten"
+  },
+  "he": {
+    "cmd.drawing_template_list": "רשימת תבניות שרטוט"
+  },
+  "ja": {
+    "cmd.drawing_template_list": "図面テンプレートを一覧表示"
+  },
+  "ko": {
+    "cmd.drawing_template_list": "도면 템플릿 목록"
+  },
+  "vi": {
+    "cmd.drawing_template_list": "Liệt kê mẫu bản vẽ"
+  },
+  "zh": {
+    "cmd.drawing_template_list": "列出绘图模板"
+  }
+}

assets/locales/pending/drawing-view-create.json

@@ -0,0 +1,26 @@
+{
+  "en": {
+    "cmd.drawing_view_base": "Base View",
+    "cmd.drawing_view_projected": "Projected View"
+  },
+  "ar": {
+    "cmd.drawing_view_base": "العرض الأساسي",
+    "cmd.drawing_view_projected": "العرض المُسقط"
+  },
+  "he": {
+    "cmd.drawing_view_base": "תצוגת בסיס",
+    "cmd.drawing_view_projected": "תצוגה מוטלת"
+  },
+  "ja": {
+    "cmd.drawing_view_base": "ベースビュー",
+    "cmd.drawing_view_projected": "投影ビュー"
+  },
+  "vi": {
+    "cmd.drawing_view_base": "Chế độ xem cơ sở",
+    "cmd.drawing_view_projected": "Chế độ xem chiếu"
+  },
+  "zh": {
+    "cmd.drawing_view_base": "基础视图",
+    "cmd.drawing_view_projected": "投影视图"
+  }
+}

assets/locales/pending/drawing-workspace-ui.json

@@ -0,0 +1,834 @@
+{
+  "ar": {
+    "0 objects": "0 عناصر",
+    "ASSEMBLY": "التجميع",
+    "Add Drawing Revision": "إضافة مراجعة للوحة",
+    "Add Revision": "إضافة مراجعة",
+    "Add sheet (not implemented)": "إضافة ورقة (غير منفّذ)",
+    "Align Annotations": "محاذاة التعليقات التوضيحية",
+    "Align Notes": "محاذاة الملاحظات",
+    "Align Views": "محاذاة المساقط",
+    "Annotate": "إضافة تعليقات توضيحية",
+    "Apply (not implemented)": "تطبيق (غير منفّذ)",
+    "Auto (Theme)": "تلقائي (السمة)",
+    "Balloon": "بالون",
+    "Base View": "المسقط الأساسي",
+    "Border & template": "الإطار والقالب",
+    "Browse Drawing Resources": "تصفح موارد اللوحات",
+    "CHANGES": "التغييرات",
+    "Centre Mark": "علامة المركز",
+    "Check Drawing": "فحص اللوحة",
+    "Close drawing panel": "إغلاق لوحة إعدادات الرسم",
+    "DRAWING ANNOTATE": "تعليقات اللوحة",
+    "DRAWING LAYOUT": "تخطيط اللوحة",
+    "DRAWING PARTS": "أجزاء اللوحة",
+    "DRAWING REVIEW": "مراجعة اللوحة",
+    "Datum": "مرجع",
+    "Detail View": "مسقط تفصيلي",
+    "Dock at bottom": "إرساء في الأسفل",
+    "Dock at top": "إرساء في الأعلى",
+    "Dock beneath Browser": "إرساء أسفل المتصفح",
+    "Dock left": "إرساء يسارًا",
+    "Dock right": "إرساء يمينًا",
+    "Dock sheet tabs": "إرساء علامات تبويب الأوراق",
+    "Drafting defaults": "إعدادات الرسم الافتراضية",
+    "Drawing & title block": "اللوحة وخانة العنوان",
+    "Drawing Dimension": "بُعد اللوحة",
+    "Drawing Line": "خط اللوحة",
+    "Drawing Note": "ملاحظة اللوحة",
+    "Drawing defaults (not available)": "إعدادات اللوحة الافتراضية (غير متاحة)",
+    "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.": "لم تُنفّذ ملفات اللوحات ولا عارض الورق بعد. تعرض الأدوات المخطط لها خياراتها حيثما حُدّدت.",
+    "Drawing workspace": "مساحة عمل اللوحات",
+    "Edit Drawing Table": "تعديل جدول اللوحة",
+    "Edit Table": "تعديل الجدول",
+    "Export Drawing": "تصدير اللوحة",
+    "Finish the current operation before entering Drawing": "أكمل العملية الحالية قبل الدخول إلى مساحة اللوحات",
+    "Hole Callout": "بيان الثقب",
+    "Image": "صورة",
+    "Inherited from parent view": "موروث من المسقط الأصل",
+    "Insert Image": "إدراج صورة",
+    "Leader": "خط إشارة",
+    "Leader Note": "ملاحظة بخط إشارة",
+    "Manage sheets (not implemented)": "إدارة الأوراق (غير منفّذ)",
+    "Manage sheets and docking": "إدارة الأوراق والإرساء",
+    "NOTES": "الملاحظات",
+    "No drawing document": "لا يوجد مستند لوحة",
+    "No drawing geometry available": "لا تتوفر هندسة للوحة",
+    "No drawing objects": "لا توجد عناصر في اللوحة",
+    "No drawing sheet is available yet.": "لا تتوفر ورقة لوحة بعد.",
+    "No drawing view available": "لا يتوفر مسقط للوحة",
+    "No sheet available": "لا تتوفر ورقة",
+    "Not available": "غير متاح",
+    "Not configured": "غير مُعدّ",
+    "Not implemented. These options describe the planned interface; no drawing data is changed.": "غير منفّذ. تصف هذه الخيارات الواجهة المخطط لها؛ لا تتغير أي بيانات للوحة.",
+    "Note": "ملاحظة",
+    "Paper & layout": "الورق والتخطيط",
+    "Paper colour": "لون الورق",
+    "Paper colour will be available when the sheet renderer is implemented.": "سيتوفر لون الورق عند تنفيذ عارض الورقة.",
+    "Parent view": "المسقط الأصل",
+    "Parts & Tables": "الأجزاء والجداول",
+    "Parts List": "قائمة الأجزاء",
+    "Print": "طباعة",
+    "Print Drawing": "طباعة اللوحة",
+    "Profile & units": "ملف التعريف والوحدات",
+    "Projected View": "مسقط مشتق بالإسقاط",
+    "RESOURCES": "الموارد",
+    "REVISION": "المراجعة",
+    "References": "المراجع",
+    "Resources": "الموارد",
+    "Return to Design to use this command.": "عُد إلى مساحة التصميم لاستخدام هذا الأمر.",
+    "Review": "مراجعة",
+    "Revision Table": "جدول المراجعات",
+    "Revision Tbl.": "جدول المراجعات",
+    "SOURCE": "المصدر",
+    "SYMBOLS": "الرموز",
+    "Screen appearance": "مظهر الشاشة",
+    "Section View": "مسقط مقطعي",
+    "Sheet Settings": "إعدادات الورقة",
+    "Sheet unavailable": "الورقة غير متاحة",
+    "Size & orientation": "الحجم والاتجاه",
+    "Source BOM": "قائمة مواد المصدر",
+    "Source Flat": "النمط المسطح للمصدر",
+    "Source design": "التصميم المصدر",
+    "Source properties": "خصائص المصدر",
+    "Space": "توزيع المسافات",
+    "Space Annotations": "توزيع المسافات بين التعليقات التوضيحية",
+    "Space Notes": "توزيع المسافات بين الملاحظات",
+    "TABLES": "الجداول",
+    "Text style": "نمط النص",
+    "Title": "العنوان",
+    "Title block": "خانة العنوان",
+    "UI preview": "معاينة الواجهة",
+    "Units & precision": "الوحدات والدقة",
+    "Update Drawing": "تحديث اللوحة",
+    "View": "مسقط"
+  },
+  "he": {
+    "0 objects": "0 עצמים",
+    "ASSEMBLY": "מכלול",
+    "Add Drawing Revision": "הוספת גרסה לשרטוט",
+    "Add Revision": "הוספת גרסה",
+    "Add sheet (not implemented)": "הוספת גיליון (טרם מומש)",
+    "Align Annotations": "יישור הערות הסבר",
+    "Align Notes": "יישור הערות",
+    "Align Views": "יישור מבטים",
+    "Annotate": "הוספת הערות הסבר",
+    "Apply (not implemented)": "החלה (טרם מומש)",
+    "Auto (Theme)": "אוטומטי (ערכת נושא)",
+    "Balloon": "בלון",
+    "Base View": "מבט בסיס",
+    "Border & template": "מסגרת ותבנית",
+    "Browse Drawing Resources": "עיון במשאבי שרטוט",
+    "CHANGES": "שינויים",
+    "Centre Mark": "סימון מרכז",
+    "Check Drawing": "בדיקת שרטוט",
+    "Close drawing panel": "סגירת לוח השרטוט",
+    "DRAWING ANNOTATE": "הערות הסבר בשרטוט",
+    "DRAWING LAYOUT": "פריסת שרטוט",
+    "DRAWING PARTS": "חלקים בשרטוט",
+    "DRAWING REVIEW": "סקירת שרטוט",
+    "Datum": "ייחוס",
+    "Detail View": "מבט מפורט",
+    "Dock at bottom": "עיגון בתחתית",
+    "Dock at top": "עיגון בראש החלון",
+    "Dock beneath Browser": "עיגון מתחת לדפדפן",
+    "Dock left": "עיגון משמאל",
+    "Dock right": "עיגון מימין",
+    "Dock sheet tabs": "עיגון לשוניות הגיליונות",
+    "Drafting defaults": "ברירות מחדל לשרטוט",
+    "Drawing & title block": "שרטוט וטבלת כותרת",
+    "Drawing Dimension": "מידת שרטוט",
+    "Drawing Line": "קו שרטוט",
+    "Drawing Note": "הערת שרטוט",
+    "Drawing defaults (not available)": "ברירות מחדל לשרטוט (לא זמינות)",
+    "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.": "קובצי שרטוט ומנגנון רינדור הנייר טרם מומשו. כלים מתוכננים מציגים את האפשרויות שלהם במקומות שבהם הוגדרו.",
+    "Drawing workspace": "סביבת עבודה לשרטוט",
+    "Edit Drawing Table": "עריכת טבלת שרטוט",
+    "Edit Table": "עריכת טבלה",
+    "Export Drawing": "ייצוא שרטוט",
+    "Finish the current operation before entering Drawing": "יש לסיים את הפעולה הנוכחית לפני המעבר לסביבת השרטוט",
+    "Hole Callout": "ציון פרטי קדח",
+    "Image": "תמונה",
+    "Inherited from parent view": "בירושה ממבט האב",
+    "Insert Image": "הוספת תמונה",
+    "Leader": "קו הפניה",
+    "Leader Note": "הערה עם קו הפניה",
+    "Manage sheets (not implemented)": "ניהול גיליונות (טרם מומש)",
+    "Manage sheets and docking": "ניהול גיליונות ועיגון",
+    "NOTES": "הערות",
+    "No drawing document": "אין מסמך שרטוט",
+    "No drawing geometry available": "אין גאומטריית שרטוט זמינה",
+    "No drawing objects": "אין עצמים בשרטוט",
+    "No drawing sheet is available yet.": "אין עדיין גיליון שרטוט זמין.",
+    "No drawing view available": "אין מבט שרטוט זמין",
+    "No sheet available": "אין גיליון זמין",
+    "Not available": "לא זמין",
+    "Not configured": "לא מוגדר",
+    "Not implemented. These options describe the planned interface; no drawing data is changed.": "טרם מומש. האפשרויות האלה מתארות את הממשק המתוכנן; נתוני השרטוט אינם משתנים.",
+    "Note": "הערה",
+    "Paper & layout": "נייר ופריסה",
+    "Paper colour": "צבע הנייר",
+    "Paper colour will be available when the sheet renderer is implemented.": "צבע הנייר יהיה זמין כאשר ימומש מנגנון רינדור הגיליון.",
+    "Parent view": "מבט אב",
+    "Parts & Tables": "חלקים וטבלאות",
+    "Parts List": "רשימת חלקים",
+    "Print": "הדפסה",
+    "Print Drawing": "הדפסת שרטוט",
+    "Profile & units": "פרופיל ויחידות",
+    "Projected View": "מבט מוטל",
+    "RESOURCES": "משאבים",
+    "REVISION": "גרסה",
+    "References": "הפניות",
+    "Resources": "משאבים",
+    "Return to Design to use this command.": "יש לחזור לסביבת התכן כדי להשתמש בפקודה זו.",
+    "Review": "סקירה",
+    "Revision Table": "טבלת גרסאות",
+    "Revision Tbl.": "טבלת גרסאות",
+    "SOURCE": "מקור",
+    "SYMBOLS": "סמלים",
+    "Screen appearance": "מראה המסך",
+    "Section View": "מבט חתך",
+    "Sheet Settings": "הגדרות גיליון",
+    "Sheet unavailable": "הגיליון אינו זמין",
+    "Size & orientation": "גודל וכיוון",
+    "Source BOM": "רשימת חלקים של המקור",
+    "Source Flat": "פריסת המקור",
+    "Source design": "תכן המקור",
+    "Source properties": "מאפייני המקור",
+    "Space": "ריווח",
+    "Space Annotations": "ריווח הערות הסבר",
+    "Space Notes": "ריווח הערות",
+    "TABLES": "טבלאות",
+    "Text style": "סגנון טקסט",
+    "Title": "כותרת",
+    "Title block": "טבלת כותרת",
+    "UI preview": "תצוגה מקדימה של הממשק",
+    "Units & precision": "יחידות ודיוק",
+    "Update Drawing": "עדכון שרטוט",
+    "View": "מבט"
+  },
+  "vi": {
+    "0 objects": "0 đối tượng",
+    "ASSEMBLY": "CỤM LẮP RÁP",
+    "Add Drawing Revision": "Thêm lần sửa đổi bản vẽ",
+    "Add Revision": "Thêm lần sửa đổi",
+    "Add sheet (not implemented)": "Thêm tờ (chưa triển khai)",
+    "Align Annotations": "Căn chỉnh chú thích",
+    "Align Notes": "Căn chỉnh ghi chú",
+    "Align Views": "Căn chỉnh hình chiếu",
+    "Annotate": "Thêm chú thích",
+    "Apply (not implemented)": "Áp dụng (chưa triển khai)",
+    "Auto (Theme)": "Tự động (theo giao diện)",
+    "Balloon": "Bóng chú thích",
+    "Base View": "Hình chiếu cơ sở",
+    "Border & template": "Khung viền và mẫu",
+    "Browse Drawing Resources": "Duyệt tài nguyên bản vẽ",
+    "CHANGES": "THAY ĐỔI",
+    "Centre Mark": "Dấu tâm",
+    "Check Drawing": "Kiểm tra bản vẽ",
+    "Close drawing panel": "Đóng bảng bản vẽ",
+    "DRAWING ANNOTATE": "CHÚ THÍCH BẢN VẼ",
+    "DRAWING LAYOUT": "BỐ CỤC BẢN VẼ",
+    "DRAWING PARTS": "CHI TIẾT BẢN VẼ",
+    "DRAWING REVIEW": "RÀ SOÁT BẢN VẼ",
+    "Datum": "Chuẩn",
+    "Detail View": "Hình chiếu chi tiết",
+    "Dock at bottom": "Gắn ở cạnh dưới",
+    "Dock at top": "Gắn ở cạnh trên",
+    "Dock beneath Browser": "Gắn bên dưới cây thư mục",
+    "Dock left": "Gắn bên trái",
+    "Dock right": "Gắn bên phải",
+    "Dock sheet tabs": "Gắn các thẻ tờ bản vẽ",
+    "Drafting defaults": "Thiết lập mặc định khi lập bản vẽ",
+    "Drawing & title block": "Bản vẽ và khung tên",
+    "Drawing Dimension": "Kích thước bản vẽ",
+    "Drawing Line": "Đường bản vẽ",
+    "Drawing Note": "Ghi chú bản vẽ",
+    "Drawing defaults (not available)": "Thiết lập mặc định của bản vẽ (chưa có)",
+    "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.": "Tệp bản vẽ và bộ kết xuất trang giấy chưa được triển khai. Các công cụ dự kiến hiển thị tùy chọn ở những nơi đã được định nghĩa.",
+    "Drawing workspace": "Không gian làm việc bản vẽ",
+    "Edit Drawing Table": "Sửa bảng trong bản vẽ",
+    "Edit Table": "Sửa bảng",
+    "Export Drawing": "Xuất bản vẽ",
+    "Finish the current operation before entering Drawing": "Hoàn tất thao tác hiện tại trước khi chuyển sang không gian Bản vẽ",
+    "Hole Callout": "Chú dẫn lỗ",
+    "Image": "Hình ảnh",
+    "Inherited from parent view": "Kế thừa từ hình chiếu gốc",
+    "Insert Image": "Chèn hình ảnh",
+    "Leader": "Đường dẫn chú thích",
+    "Leader Note": "Ghi chú có đường dẫn",
+    "Manage sheets (not implemented)": "Quản lý tờ (chưa triển khai)",
+    "Manage sheets and docking": "Quản lý tờ và vị trí gắn",
+    "NOTES": "GHI CHÚ",
+    "No drawing document": "Không có tài liệu bản vẽ",
+    "No drawing geometry available": "Chưa có hình học bản vẽ",
+    "No drawing objects": "Không có đối tượng bản vẽ",
+    "No drawing sheet is available yet.": "Chưa có tờ bản vẽ nào.",
+    "No drawing view available": "Chưa có hình chiếu bản vẽ",
+    "No sheet available": "Chưa có tờ",
+    "Not available": "Chưa có",
+    "Not configured": "Chưa cấu hình",
+    "Not implemented. These options describe the planned interface; no drawing data is changed.": "Chưa triển khai. Các tùy chọn này mô tả giao diện dự kiến; không có dữ liệu bản vẽ nào bị thay đổi.",
+    "Note": "Ghi chú",
+    "Paper & layout": "Giấy và bố cục",
+    "Paper colour": "Màu giấy",
+    "Paper colour will be available when the sheet renderer is implemented.": "Có thể chọn màu giấy khi bộ kết xuất tờ bản vẽ được triển khai.",
+    "Parent view": "Hình chiếu gốc",
+    "Parts & Tables": "Chi tiết và bảng",
+    "Parts List": "Danh sách chi tiết",
+    "Print": "In",
+    "Print Drawing": "In bản vẽ",
+    "Profile & units": "Hồ sơ và đơn vị",
+    "Projected View": "Hình chiếu dẫn xuất",
+    "RESOURCES": "TÀI NGUYÊN",
+    "REVISION": "LẦN SỬA ĐỔI",
+    "References": "Tham chiếu",
+    "Resources": "Tài nguyên",
+    "Return to Design to use this command.": "Quay lại không gian Thiết kế để dùng lệnh này.",
+    "Review": "Rà soát",
+    "Revision Table": "Bảng sửa đổi",
+    "Revision Tbl.": "Bảng sửa đổi",
+    "SOURCE": "NGUỒN",
+    "SYMBOLS": "KÝ HIỆU",
+    "Screen appearance": "Diện mạo trên màn hình",
+    "Section View": "Hình cắt",
+    "Sheet Settings": "Cài đặt tờ",
+    "Sheet unavailable": "Tờ không khả dụng",
+    "Size & orientation": "Kích thước và hướng",
+    "Source BOM": "Bảng kê vật tư nguồn",
+    "Source Flat": "Bản trải phẳng nguồn",
+    "Source design": "Thiết kế nguồn",
+    "Source properties": "Thuộc tính nguồn",
+    "Space": "Giãn cách",
+    "Space Annotations": "Giãn cách chú thích",
+    "Space Notes": "Giãn cách ghi chú",
+    "TABLES": "BẢNG",
+    "Text style": "Kiểu chữ",
+    "Title": "Tiêu đề",
+    "Title block": "Khung tên",
+    "UI preview": "Xem trước giao diện",
+    "Units & precision": "Đơn vị và độ chính xác",
+    "Update Drawing": "Cập nhật bản vẽ",
+    "View": "Hình chiếu"
+  },
+  "en": {
+    "0 objects": "0 objects",
+    "ASSEMBLY": "ASSEMBLY",
+    "Add Drawing Revision": "Add Drawing Revision",
+    "Add Revision": "Add Revision",
+    "Add sheet (not implemented)": "Add sheet (not implemented)",
+    "Align Annotations": "Align Annotations",
+    "Align Notes": "Align Notes",
+    "Align Views": "Align Views",
+    "Annotate": "Annotate",
+    "Apply (not implemented)": "Apply (not implemented)",
+    "Auto (Theme)": "Auto (Theme)",
+    "Balloon": "Balloon",
+    "Base View": "Base View",
+    "Border & template": "Border & template",
+    "Browse Drawing Resources": "Browse Drawing Resources",
+    "CHANGES": "CHANGES",
+    "Centre Mark": "Centre Mark",
+    "Check Drawing": "Check Drawing",
+    "Close drawing panel": "Close drawing panel",
+    "DRAWING ANNOTATE": "DRAWING ANNOTATE",
+    "DRAWING LAYOUT": "DRAWING LAYOUT",
+    "DRAWING PARTS": "DRAWING PARTS",
+    "DRAWING REVIEW": "DRAWING REVIEW",
+    "Datum": "Datum",
+    "Detail View": "Detail View",
+    "Dock at bottom": "Dock at bottom",
+    "Dock at top": "Dock at top",
+    "Dock beneath Browser": "Dock beneath Browser",
+    "Dock left": "Dock left",
+    "Dock right": "Dock right",
+    "Dock sheet tabs": "Dock sheet tabs",
+    "Drafting defaults": "Drafting defaults",
+    "Drawing & title block": "Drawing & title block",
+    "Drawing Dimension": "Drawing Dimension",
+    "Drawing Line": "Drawing Line",
+    "Drawing Note": "Drawing Note",
+    "Drawing defaults (not available)": "Drawing defaults (not available)",
+    "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.": "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.",
+    "Drawing workspace": "Drawing workspace",
+    "Edit Drawing Table": "Edit Drawing Table",
+    "Edit Table": "Edit Table",
+    "Export Drawing": "Export Drawing",
+    "Finish the current operation before entering Drawing": "Finish the current operation before entering Drawing",
+    "Hole Callout": "Hole Callout",
+    "Image": "Image",
+    "Inherited from parent view": "Inherited from parent view",
+    "Insert Image": "Insert Image",
+    "Leader": "Leader",
+    "Leader Note": "Leader Note",
+    "Manage sheets (not implemented)": "Manage sheets (not implemented)",
+    "Manage sheets and docking": "Manage sheets and docking",
+    "NOTES": "NOTES",
+    "No drawing document": "No drawing document",
+    "No drawing geometry available": "No drawing geometry available",
+    "No drawing objects": "No drawing objects",
+    "No drawing sheet is available yet.": "No drawing sheet is available yet.",
+    "No drawing view available": "No drawing view available",
+    "No sheet available": "No sheet available",
+    "Not available": "Not available",
+    "Not configured": "Not configured",
+    "Not implemented. These options describe the planned interface; no drawing data is changed.": "Not implemented. These options describe the planned interface; no drawing data is changed.",
+    "Note": "Note",
+    "Paper & layout": "Paper & layout",
+    "Paper colour": "Paper colour",
+    "Paper colour will be available when the sheet renderer is implemented.": "Paper colour will be available when the sheet renderer is implemented.",
+    "Parent view": "Parent view",
+    "Parts & Tables": "Parts & Tables",
+    "Parts List": "Parts List",
+    "Print": "Print",
+    "Print Drawing": "Print Drawing",
+    "Profile & units": "Profile & units",
+    "Projected View": "Projected View",
+    "RESOURCES": "RESOURCES",
+    "REVISION": "REVISION",
+    "References": "References",
+    "Resources": "Resources",
+    "Return to Design to use this command.": "Return to Design to use this command.",
+    "Review": "Review",
+    "Revision Table": "Revision Table",
+    "Revision Tbl.": "Revision Tbl.",
+    "SOURCE": "SOURCE",
+    "SYMBOLS": "SYMBOLS",
+    "Screen appearance": "Screen appearance",
+    "Section View": "Section View",
+    "Sheet Settings": "Sheet Settings",
+    "Sheet unavailable": "Sheet unavailable",
+    "Size & orientation": "Size & orientation",
+    "Source BOM": "Source BOM",
+    "Source Flat": "Source Flat",
+    "Source design": "Source design",
+    "Source properties": "Source properties",
+    "Space": "Space",
+    "Space Annotations": "Space Annotations",
+    "Space Notes": "Space Notes",
+    "TABLES": "TABLES",
+    "Text style": "Text style",
+    "Title": "Title",
+    "Title block": "Title block",
+    "UI preview": "UI preview",
+    "Units & precision": "Units & precision",
+    "Update Drawing": "Update Drawing",
+    "View": "View"
+  },
+  "ja": {
+    "0 objects": "0個のオブジェクト",
+    "ASSEMBLY": "アセンブリ",
+    "Add Drawing Revision": "図面の改訂を追加",
+    "Add Revision": "改訂を追加",
+    "Add sheet (not implemented)": "シートを追加（未実装）",
+    "Align Annotations": "注釈を整列",
+    "Align Notes": "注記を整列",
+    "Align Views": "ビューを整列",
+    "Annotate": "注釈",
+    "Apply (not implemented)": "適用（未実装）",
+    "Auto (Theme)": "自動（テーマ）",
+    "Balloon": "バルーン",
+    "Base View": "基準ビュー",
+    "Border & template": "図枠とテンプレート",
+    "Browse Drawing Resources": "図面リソースを参照",
+    "CHANGES": "変更",
+    "Centre Mark": "中心マーク",
+    "Check Drawing": "図面をチェック",
+    "Close drawing panel": "図面パネルを閉じる",
+    "DRAWING ANNOTATE": "図面の注釈",
+    "DRAWING LAYOUT": "図面のレイアウト",
+    "DRAWING PARTS": "図面の部品",
+    "DRAWING REVIEW": "図面の確認",
+    "Datum": "データム",
+    "Detail View": "詳細ビュー",
+    "Dock at bottom": "下部にドッキング",
+    "Dock at top": "上部にドッキング",
+    "Dock beneath Browser": "ブラウザーの下にドッキング",
+    "Dock left": "左にドッキング",
+    "Dock right": "右にドッキング",
+    "Dock sheet tabs": "シートタブをドッキング",
+    "Drafting defaults": "製図の既定値",
+    "Drawing & title block": "図面と表題欄",
+    "Drawing Dimension": "図面寸法",
+    "Drawing Line": "図面の線分",
+    "Drawing Note": "図面の注記",
+    "Drawing defaults (not available)": "図面の既定値（利用不可）",
+    "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.": "図面ファイルと用紙レンダラーは未実装です。予定されているツールでは、設定項目が定義済みの場合に表示されます。",
+    "Drawing workspace": "図面ワークスペース",
+    "Edit Drawing Table": "図面の表を編集",
+    "Edit Table": "表を編集",
+    "Export Drawing": "図面をエクスポート",
+    "Finish the current operation before entering Drawing": "現在の操作を完了してから図面ワークスペースに移動してください",
+    "Hole Callout": "穴注記",
+    "Image": "画像",
+    "Inherited from parent view": "親ビューから継承",
+    "Insert Image": "画像を挿入",
+    "Leader": "引出線",
+    "Leader Note": "引出線付き注記",
+    "Manage sheets (not implemented)": "シートを管理（未実装）",
+    "Manage sheets and docking": "シートとドッキングを管理",
+    "NOTES": "注記",
+    "No drawing document": "図面ドキュメントがありません",
+    "No drawing geometry available": "利用可能な図面ジオメトリがありません",
+    "No drawing objects": "図面オブジェクトがありません",
+    "No drawing sheet is available yet.": "図面シートはまだ利用できません。",
+    "No drawing view available": "利用可能な図面ビューがありません",
+    "No sheet available": "利用可能なシートがありません",
+    "Not available": "利用不可",
+    "Not configured": "未設定",
+    "Not implemented. These options describe the planned interface; no drawing data is changed.": "未実装です。これらの設定項目は予定されているインターフェースを示すもので、図面データは変更されません。",
+    "Note": "注記",
+    "Paper & layout": "用紙とレイアウト",
+    "Paper colour": "用紙の色",
+    "Paper colour will be available when the sheet renderer is implemented.": "用紙の色はシートレンダラーの実装後に設定できます。",
+    "Parent view": "親ビュー",
+    "Parts & Tables": "部品と表",
+    "Parts List": "部品表",
+    "Print": "印刷",
+    "Print Drawing": "図面を印刷",
+    "Profile & units": "製図規格と単位",
+    "Projected View": "投影ビュー",
+    "RESOURCES": "リソース",
+    "REVISION": "改訂",
+    "References": "参照",
+    "Resources": "リソース",
+    "Return to Design to use this command.": "このコマンドを使用するには、デザインワークスペースに戻ってください。",
+    "Review": "確認",
+    "Revision Table": "改訂表",
+    "Revision Tbl.": "改訂表",
+    "SOURCE": "参照元",
+    "SYMBOLS": "記号",
+    "Screen appearance": "画面表示",
+    "Section View": "断面ビュー",
+    "Sheet Settings": "シート設定",
+    "Sheet unavailable": "シートを利用できません",
+    "Size & orientation": "サイズと向き",
+    "Source BOM": "参照元の部品表",
+    "Source Flat": "参照元の展開図",
+    "Source design": "参照元のデザイン",
+    "Source properties": "参照元のプロパティ",
+    "Space": "等間隔",
+    "Space Annotations": "注釈を等間隔に",
+    "Space Notes": "注記を等間隔に",
+    "TABLES": "表",
+    "Text style": "文字スタイル",
+    "Title": "タイトル",
+    "Title block": "表題欄",
+    "UI preview": "UIプレビュー",
+    "Units & precision": "単位と精度",
+    "Update Drawing": "図面を更新",
+    "View": "ビュー"
+  },
+  "zh": {
+    "0 objects": "0 个对象",
+    "ASSEMBLY": "装配",
+    "Add Drawing Revision": "添加图纸修订",
+    "Add Revision": "添加修订",
+    "Add sheet (not implemented)": "添加图纸页（未实现）",
+    "Align Annotations": "对齐标注",
+    "Align Notes": "对齐注释",
+    "Align Views": "对齐视图",
+    "Annotate": "标注",
+    "Apply (not implemented)": "应用（未实现）",
+    "Auto (Theme)": "自动（跟随主题）",
+    "Balloon": "零件序号",
+    "Base View": "基本视图",
+    "Border & template": "图框与模板",
+    "Browse Drawing Resources": "浏览制图资源",
+    "CHANGES": "更改",
+    "Centre Mark": "中心标记",
+    "Check Drawing": "检查图纸",
+    "Close drawing panel": "关闭制图面板",
+    "DRAWING ANNOTATE": "图纸标注",
+    "DRAWING LAYOUT": "图纸布局",
+    "DRAWING PARTS": "图纸零件",
+    "DRAWING REVIEW": "图纸审阅",
+    "Datum": "基准",
+    "Detail View": "局部放大视图",
+    "Dock at bottom": "停靠到底部",
+    "Dock at top": "停靠到顶部",
+    "Dock beneath Browser": "停靠到浏览器下方",
+    "Dock left": "停靠到左侧",
+    "Dock right": "停靠到右侧",
+    "Dock sheet tabs": "停靠图纸页选项卡",
+    "Drafting defaults": "制图默认设置",
+    "Drawing & title block": "图纸与标题栏",
+    "Drawing Dimension": "图纸尺寸标注",
+    "Drawing Line": "图纸线段",
+    "Drawing Note": "图纸注释",
+    "Drawing defaults (not available)": "图纸默认设置（不可用）",
+    "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.": "图纸文件和纸张渲染器尚未实现。规划中的工具会显示已定义的选项。",
+    "Drawing workspace": "工程图工作区",
+    "Edit Drawing Table": "编辑图纸表格",
+    "Edit Table": "编辑表格",
+    "Export Drawing": "导出图纸",
+    "Finish the current operation before entering Drawing": "请先完成当前操作，再进入工程图工作区",
+    "Hole Callout": "孔标注",
+    "Image": "图像",
+    "Inherited from parent view": "继承父视图",
+    "Insert Image": "插入图像",
+    "Leader": "引线",
+    "Leader Note": "引线注释",
+    "Manage sheets (not implemented)": "管理图纸页（未实现）",
+    "Manage sheets and docking": "管理图纸页与停靠位置",
+    "NOTES": "注释",
+    "No drawing document": "没有图纸文档",
+    "No drawing geometry available": "没有可用的图纸几何",
+    "No drawing objects": "没有图纸对象",
+    "No drawing sheet is available yet.": "目前尚无可用的图纸页。",
+    "No drawing view available": "没有可用的图纸视图",
+    "No sheet available": "没有可用的图纸页",
+    "Not available": "不可用",
+    "Not configured": "未配置",
+    "Not implemented. These options describe the planned interface; no drawing data is changed.": "尚未实现。这些选项展示规划中的界面，不会更改任何图纸数据。",
+    "Note": "注释",
+    "Paper & layout": "纸张与布局",
+    "Paper colour": "纸张颜色",
+    "Paper colour will be available when the sheet renderer is implemented.": "图纸页渲染器实现后即可设置纸张颜色。",
+    "Parent view": "父视图",
+    "Parts & Tables": "零件与表格",
+    "Parts List": "零件明细表",
+    "Print": "打印",
+    "Print Drawing": "打印图纸",
+    "Profile & units": "制图规范与单位",
+    "Projected View": "投影视图",
+    "RESOURCES": "资源",
+    "REVISION": "修订",
+    "References": "引用",
+    "Resources": "资源",
+    "Return to Design to use this command.": "请返回设计工作区使用此命令。",
+    "Review": "审阅",
+    "Revision Table": "修订表",
+    "Revision Tbl.": "修订表",
+    "SOURCE": "源设计",
+    "SYMBOLS": "符号",
+    "Screen appearance": "屏幕外观",
+    "Section View": "剖视图",
+    "Sheet Settings": "图纸页设置",
+    "Sheet unavailable": "图纸页不可用",
+    "Size & orientation": "尺寸与方向",
+    "Source BOM": "源设计 BOM",
+    "Source Flat": "源设计展开图",
+    "Source design": "源设计",
+    "Source properties": "源设计属性",
+    "Space": "均布",
+    "Space Annotations": "等间距分布标注",
+    "Space Notes": "等间距分布注释",
+    "TABLES": "表格",
+    "Text style": "文字样式",
+    "Title": "标题",
+    "Title block": "标题栏",
+    "UI preview": "界面预览",
+    "Units & precision": "单位与精度",
+    "Update Drawing": "更新图纸",
+    "View": "视图"
+  },
+  "de": {
+    "0 objects": "0 Objekte",
+    "ASSEMBLY": "BAUGRUPPE",
+    "Add Drawing Revision": "Zeichnungsrevision hinzufügen",
+    "Add Revision": "Revision hinzufügen",
+    "Add sheet (not implemented)": "Blatt hinzufügen (nicht implementiert)",
+    "Align Annotations": "Beschriftungen ausrichten",
+    "Align Notes": "Hinweise ausrichten",
+    "Align Views": "Ansichten ausrichten",
+    "Annotate": "Beschriften",
+    "Apply (not implemented)": "Anwenden (nicht implementiert)",
+    "Auto (Theme)": "Automatisch (Design)",
+    "Balloon": "Positionssymbol",
+    "Base View": "Basisansicht",
+    "Border & template": "Rahmen & Vorlage",
+    "Browse Drawing Resources": "Zeichnungsressourcen durchsuchen",
+    "CHANGES": "ÄNDERUNGEN",
+    "Centre Mark": "Mittelpunktmarkierung",
+    "Check Drawing": "Zeichnung prüfen",
+    "Close drawing panel": "Zeichnungspanel schließen",
+    "DRAWING ANNOTATE": "ZEICHNUNG BESCHRIFTEN",
+    "DRAWING LAYOUT": "ZEICHNUNGSLAYOUT",
+    "DRAWING PARTS": "ZEICHNUNGSTEILE",
+    "DRAWING REVIEW": "ZEICHNUNGSPRÜFUNG",
+    "Datum": "Bezug",
+    "Detail View": "Detailansicht",
+    "Dock at bottom": "Unten andocken",
+    "Dock at top": "Oben andocken",
+    "Dock beneath Browser": "Unter dem Browser andocken",
+    "Dock left": "Links andocken",
+    "Dock right": "Rechts andocken",
+    "Dock sheet tabs": "Blattregister andocken",
+    "Drafting defaults": "Vorgaben für die Zeichnungserstellung",
+    "Drawing & title block": "Zeichnung & Schriftfeld",
+    "Drawing Dimension": "Zeichnungsbemaßung",
+    "Drawing Line": "Zeichnungslinie",
+    "Drawing Note": "Zeichnungshinweis",
+    "Drawing defaults (not available)": "Zeichnungsvorgaben (nicht verfügbar)",
+    "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.": "Zeichnungsdateien und die Papierdarstellung sind noch nicht implementiert. Geplante Werkzeuge zeigen ihre Optionen an, sofern diese bereits festgelegt sind.",
+    "Drawing workspace": "Zeichnungsarbeitsbereich",
+    "Edit Drawing Table": "Zeichnungstabelle bearbeiten",
+    "Edit Table": "Tabelle bearbeiten",
+    "Export Drawing": "Zeichnung exportieren",
+    "Finish the current operation before entering Drawing": "Beenden Sie den aktuellen Vorgang, bevor Sie zum Zeichnungsarbeitsbereich wechseln",
+    "Hole Callout": "Bohrungsangabe",
+    "Image": "Bild",
+    "Inherited from parent view": "Von der übergeordneten Ansicht übernommen",
+    "Insert Image": "Bild einfügen",
+    "Leader": "Bezugslinie",
+    "Leader Note": "Hinweis mit Bezugslinie",
+    "Manage sheets (not implemented)": "Blätter verwalten (nicht implementiert)",
+    "Manage sheets and docking": "Blätter und Andockpositionen verwalten",
+    "NOTES": "HINWEISE",
+    "No drawing document": "Kein Zeichnungsdokument",
+    "No drawing geometry available": "Keine Zeichnungsgeometrie verfügbar",
+    "No drawing objects": "Keine Zeichnungsobjekte",
+    "No drawing sheet is available yet.": "Es ist noch kein Zeichnungsblatt verfügbar.",
+    "No drawing view available": "Keine Zeichnungsansicht verfügbar",
+    "No sheet available": "Kein Blatt verfügbar",
+    "Not available": "Nicht verfügbar",
+    "Not configured": "Nicht konfiguriert",
+    "Not implemented. These options describe the planned interface; no drawing data is changed.": "Nicht implementiert. Diese Optionen beschreiben die geplante Oberfläche; es werden keine Zeichnungsdaten geändert.",
+    "Note": "Hinweis",
+    "Paper & layout": "Papier & Layout",
+    "Paper colour": "Papierfarbe",
+    "Paper colour will be available when the sheet renderer is implemented.": "Die Papierfarbe wird verfügbar sein, sobald die Blattdarstellung implementiert ist.",
+    "Parent view": "Übergeordnete Ansicht",
+    "Parts & Tables": "Teile & Tabellen",
+    "Parts List": "Teileliste",
+    "Print": "Drucken",
+    "Print Drawing": "Zeichnung drucken",
+    "Profile & units": "Profil & Einheiten",
+    "Projected View": "Projizierte Ansicht",
+    "RESOURCES": "RESSOURCEN",
+    "REVISION": "REVISION",
+    "References": "Referenzen",
+    "Resources": "Ressourcen",
+    "Return to Design to use this command.": "Wechseln Sie zum Design-Arbeitsbereich zurück, um diesen Befehl zu verwenden.",
+    "Review": "Prüfen",
+    "Revision Table": "Revisionstabelle",
+    "Revision Tbl.": "Revisionstbl.",
+    "SOURCE": "QUELLE",
+    "SYMBOLS": "SYMBOLE",
+    "Screen appearance": "Bildschirmdarstellung",
+    "Section View": "Schnittansicht",
+    "Sheet Settings": "Blatteinstellungen",
+    "Sheet unavailable": "Blatt nicht verfügbar",
+    "Size & orientation": "Größe & Ausrichtung",
+    "Source BOM": "Stückliste der Quelle",
+    "Source Flat": "Flachmuster der Quelle",
+    "Source design": "Quelldesign",
+    "Source properties": "Eigenschaften der Quelle",
+    "Space": "Abstände anpassen",
+    "Space Annotations": "Beschriftungsabstände anpassen",
+    "Space Notes": "Hinweisabstände anpassen",
+    "TABLES": "TABELLEN",
+    "Text style": "Textstil",
+    "Title": "Titel",
+    "Title block": "Schriftfeld",
+    "UI preview": "Oberflächenvorschau",
+    "Units & precision": "Einheiten & Genauigkeit",
+    "Update Drawing": "Zeichnung aktualisieren",
+    "View": "Ansicht"
+  },
+  "ko": {
+    "0 objects": "객체 0개",
+    "ASSEMBLY": "조립품",
+    "Add Drawing Revision": "도면 리비전 추가",
+    "Add Revision": "리비전 추가",
+    "Add sheet (not implemented)": "시트 추가 (미구현)",
+    "Align Annotations": "주석 정렬",
+    "Align Notes": "메모 정렬",
+    "Align Views": "뷰 정렬",
+    "Annotate": "주석 달기",
+    "Apply (not implemented)": "적용 (미구현)",
+    "Auto (Theme)": "자동 (테마)",
+    "Balloon": "항목 번호 기호",
+    "Base View": "기본 뷰",
+    "Border & template": "테두리 및 템플릿",
+    "Browse Drawing Resources": "도면 리소스 찾아보기",
+    "CHANGES": "변경 사항",
+    "Centre Mark": "중심 표시",
+    "Check Drawing": "도면 검사",
+    "Close drawing panel": "도면 패널 닫기",
+    "DRAWING ANNOTATE": "도면 주석",
+    "DRAWING LAYOUT": "도면 배치",
+    "DRAWING PARTS": "도면 부품",
+    "DRAWING REVIEW": "도면 검토",
+    "Datum": "기준",
+    "Detail View": "상세 뷰",
+    "Dock at bottom": "아래쪽에 고정",
+    "Dock at top": "위쪽에 고정",
+    "Dock beneath Browser": "브라우저 아래에 고정",
+    "Dock left": "왼쪽에 고정",
+    "Dock right": "오른쪽에 고정",
+    "Dock sheet tabs": "시트 탭 고정",
+    "Drafting defaults": "도면 작성 기본 설정",
+    "Drawing & title block": "도면 및 표제란",
+    "Drawing Dimension": "도면 치수",
+    "Drawing Line": "도면 선",
+    "Drawing Note": "도면 메모",
+    "Drawing defaults (not available)": "도면 기본 설정 (사용 불가)",
+    "Drawing files and the paper renderer are not implemented. Planned tools show their options where defined.": "도면 파일과 용지 렌더러는 아직 구현되지 않았습니다. 예정된 도구는 정의된 옵션이 있는 경우 해당 옵션을 표시합니다.",
+    "Drawing workspace": "도면 작업 공간",
+    "Edit Drawing Table": "도면 표 편집",
+    "Edit Table": "표 편집",
+    "Export Drawing": "도면 내보내기",
+    "Finish the current operation before entering Drawing": "도면 작업 공간으로 전환하기 전에 현재 작업을 완료하세요",
+    "Hole Callout": "구멍 주석",
+    "Image": "이미지",
+    "Inherited from parent view": "상위 뷰에서 상속됨",
+    "Insert Image": "이미지 삽입",
+    "Leader": "지시선",
+    "Leader Note": "지시선 메모",
+    "Manage sheets (not implemented)": "시트 관리 (미구현)",
+    "Manage sheets and docking": "시트 및 고정 위치 관리",
+    "NOTES": "메모",
+    "No drawing document": "도면 문서 없음",
+    "No drawing geometry available": "사용 가능한 도면 형상 없음",
+    "No drawing objects": "도면 객체 없음",
+    "No drawing sheet is available yet.": "아직 사용 가능한 도면 시트가 없습니다.",
+    "No drawing view available": "사용 가능한 도면 뷰 없음",
+    "No sheet available": "사용 가능한 시트 없음",
+    "Not available": "사용 불가",
+    "Not configured": "설정되지 않음",
+    "Not implemented. These options describe the planned interface; no drawing data is changed.": "아직 구현되지 않았습니다. 이 옵션은 예정된 인터페이스를 설명하며 도면 데이터를 변경하지 않습니다.",
+    "Note": "메모",
+    "Paper & layout": "용지 및 배치",
+    "Paper colour": "용지 색상",
+    "Paper colour will be available when the sheet renderer is implemented.": "시트 렌더러가 구현되면 용지 색상을 설정할 수 있습니다.",
+    "Parent view": "상위 뷰",
+    "Parts & Tables": "부품 및 표",
+    "Parts List": "부품 목록",
+    "Print": "인쇄",
+    "Print Drawing": "도면 인쇄",
+    "Profile & units": "프로파일 및 단위",
+    "Projected View": "투영 뷰",
+    "RESOURCES": "리소스",
+    "REVISION": "리비전",
+    "References": "참조",
+    "Resources": "리소스",
+    "Return to Design to use this command.": "이 명령을 사용하려면 디자인 작업 공간으로 돌아가세요.",
+    "Review": "검토",
+    "Revision Table": "리비전 표",
+    "Revision Tbl.": "리비전 표",
+    "SOURCE": "원본",
+    "SYMBOLS": "기호",
+    "Screen appearance": "화면 모양",
+    "Section View": "단면 뷰",
+    "Sheet Settings": "시트 설정",
+    "Sheet unavailable": "시트 사용 불가",
+    "Size & orientation": "크기 및 방향",
+    "Source BOM": "원본 자재 명세서",
+    "Source Flat": "원본 전개도",
+    "Source design": "원본 디자인",
+    "Source properties": "원본 속성",
+    "Space": "간격 조정",
+    "Space Annotations": "주석 간격 조정",
+    "Space Notes": "메모 간격 조정",
+    "TABLES": "표",
+    "Text style": "텍스트 스타일",
+    "Title": "제목",
+    "Title block": "표제란",
+    "UI preview": "인터페이스 미리보기",
+    "Units & precision": "단위 및 정밀도",
+    "Update Drawing": "도면 업데이트",
+    "View": "뷰"
+  }
+}

assets/locales/pending/drawings-sync-oct30.json

@@ -0,0 +1,119 @@
+{
+  "ar": {
+    "cmd.assembly_bom_item_set": "تغيير رقم البند",
+    "cmd.assembly_bom_renumber": "إعادة ترقيم البنود",
+    "cmd.drawing_balloon_add": "إضافة بالون",
+    "cmd.drawing_balloon_edit": "تعديل البالون",
+    "cmd.drawing_balloon_inspect": "فحص البالون",
+    "cmd.drawing_close": "إغلاق اللوحة",
+    "cmd.drawing_create": "إنشاء لوحة",
+    "cmd.drawing_delete": "حذف اللوحة",
+    "cmd.drawing_dimension_add": "إضافة بُعد إلى اللوحة",
+    "cmd.drawing_dimension_edit": "تعديل بُعد اللوحة",
+    "cmd.drawing_dimension_inspect": "فحص بُعد اللوحة",
+    "cmd.drawing_export": "تصدير الورقة",
+    "cmd.drawing_inspect": "فحص اللوحة",
+    "cmd.drawing_list": "سرد اللوحات",
+    "cmd.drawing_open": "فتح اللوحة",
+    "cmd.drawing_properties": "خصائص اللوحة",
+    "cmd.drawing_properties_remove": "إزالة خاصية اللوحة",
+    "cmd.drawing_properties_set": "تغيير خصائص اللوحة",
+    "cmd.drawing_revision_add": "إضافة مراجعة",
+    "cmd.drawing_revision_delete": "حذف المراجعة",
+    "cmd.drawing_revision_edit": "تعديل المراجعة",
+    "cmd.drawing_scene": "رسم الورقة",
+    "cmd.drawing_set": "إعدادات اللوحة",
+    "cmd.drawing_sheet_add": "إضافة ورقة",
+    "cmd.drawing_sheet_delete": "حذف الورقة",
+    "cmd.drawing_sheet_reorder": "إعادة ترتيب الأوراق",
+    "cmd.drawing_sheet_set": "إعدادات الورقة",
+    "cmd.drawing_view_copy_to_sheet": "نسخ المسقط إلى ورقة",
+    "cmd.drawing_view_edit": "تعديل مسقط اللوحة",
+    "cmd.drawing_view_inspect": "فحص مسقط اللوحة",
+    "cmd.drawing_view_move_to_sheet": "نقل المسقط إلى ورقة",
+    "cmd.drawing_view_snapshot": "لقطة مسقط اللوحة",
+    "cmd.occurrence_bom_type": "نوع قائمة المواد",
+    "prefs.drawings": "اللوحات",
+    "ui.first_angle": "الزاوية الأولى",
+    "ui.projection_of_new_drawings": "إسقاط اللوحات الجديدة",
+    "ui.third_angle": "الزاوية الثالثة"
+  },
+  "he": {
+    "cmd.assembly_bom_item_set": "שינוי מספר פריט",
+    "cmd.assembly_bom_renumber": "מספור מחדש של פריטים",
+    "cmd.drawing_balloon_add": "הוספת בלון",
+    "cmd.drawing_balloon_edit": "עריכת בלון",
+    "cmd.drawing_balloon_inspect": "בדיקת בלון",
+    "cmd.drawing_close": "סגירת שרטוט",
+    "cmd.drawing_create": "יצירת שרטוט",
+    "cmd.drawing_delete": "מחיקת שרטוט",
+    "cmd.drawing_dimension_add": "הוספת מידה לשרטוט",
+    "cmd.drawing_dimension_edit": "עריכת מידת שרטוט",
+    "cmd.drawing_dimension_inspect": "בדיקת מידת שרטוט",
+    "cmd.drawing_export": "ייצוא גיליון",
+    "cmd.drawing_inspect": "בדיקת שרטוט",
+    "cmd.drawing_list": "רשימת שרטוטים",
+    "cmd.drawing_open": "פתיחת שרטוט",
+    "cmd.drawing_properties": "מאפייני שרטוט",
+    "cmd.drawing_properties_remove": "הסרת מאפיין שרטוט",
+    "cmd.drawing_properties_set": "שינוי מאפייני שרטוט",
+    "cmd.drawing_revision_add": "הוספת גרסה",
+    "cmd.drawing_revision_delete": "מחיקת גרסה",
+    "cmd.drawing_revision_edit": "עריכת גרסה",
+    "cmd.drawing_scene": "ציור גיליון",
+    "cmd.drawing_set": "הגדרות שרטוט",
+    "cmd.drawing_sheet_add": "הוספת גיליון",
+    "cmd.drawing_sheet_delete": "מחיקת גיליון",
+    "cmd.drawing_sheet_reorder": "סידור גיליונות מחדש",
+    "cmd.drawing_sheet_set": "הגדרות גיליון",
+    "cmd.drawing_view_copy_to_sheet": "העתקת מבט לגיליון",
+    "cmd.drawing_view_edit": "עריכת מבט שרטוט",
+    "cmd.drawing_view_inspect": "בדיקת מבט שרטוט",
+    "cmd.drawing_view_move_to_sheet": "העברת מבט לגיליון",
+    "cmd.drawing_view_snapshot": "תמונת מבט שרטוט",
+    "cmd.occurrence_bom_type": "סוג ברשימת החלקים",
+    "prefs.drawings": "שרטוטים",
+    "ui.first_angle": "זווית ראשונה",
+    "ui.projection_of_new_drawings": "היטל של שרטוטים חדשים",
+    "ui.third_angle": "זווית שלישית"
+  },
+  "vi": {
+    "cmd.assembly_bom_item_set": "Đổi số hạng mục",
+    "cmd.assembly_bom_renumber": "Đánh số lại hạng mục",
+    "cmd.drawing_balloon_add": "Thêm bóng chú thích",
+    "cmd.drawing_balloon_edit": "Sửa bóng chú thích",
+    "cmd.drawing_balloon_inspect": "Kiểm tra bóng chú thích",
+    "cmd.drawing_close": "Đóng bản vẽ",
+    "cmd.drawing_create": "Tạo bản vẽ",
+    "cmd.drawing_delete": "Xóa bản vẽ",
+    "cmd.drawing_dimension_add": "Thêm kích thước bản vẽ",
+    "cmd.drawing_dimension_edit": "Sửa kích thước bản vẽ",
+    "cmd.drawing_dimension_inspect": "Kiểm tra kích thước bản vẽ",
+    "cmd.drawing_export": "Xuất tờ",
+    "cmd.drawing_inspect": "Kiểm tra bản vẽ",
+    "cmd.drawing_list": "Liệt kê bản vẽ",
+    "cmd.drawing_open": "Mở bản vẽ",
+    "cmd.drawing_properties": "Thuộc tính bản vẽ",
+    "cmd.drawing_properties_remove": "Xóa thuộc tính bản vẽ",
+    "cmd.drawing_properties_set": "Thay đổi thuộc tính bản vẽ",
+    "cmd.drawing_revision_add": "Thêm lần sửa đổi",
+    "cmd.drawing_revision_delete": "Xóa lần sửa đổi",
+    "cmd.drawing_revision_edit": "Sửa lần sửa đổi",
+    "cmd.drawing_scene": "Vẽ tờ",
+    "cmd.drawing_set": "Cài đặt bản vẽ",
+    "cmd.drawing_sheet_add": "Thêm tờ",
+    "cmd.drawing_sheet_delete": "Xóa tờ",
+    "cmd.drawing_sheet_reorder": "Sắp xếp lại các tờ",
+    "cmd.drawing_sheet_set": "Cài đặt tờ",
+    "cmd.drawing_view_copy_to_sheet": "Sao chép hình chiếu sang tờ",
+    "cmd.drawing_view_edit": "Sửa hình chiếu bản vẽ",
+    "cmd.drawing_view_inspect": "Kiểm tra hình chiếu bản vẽ",
+    "cmd.drawing_view_move_to_sheet": "Chuyển hình chiếu sang tờ",
+    "cmd.drawing_view_snapshot": "Ảnh chụp hình chiếu bản vẽ",
+    "cmd.occurrence_bom_type": "Loại trong bảng kê vật tư",
+    "prefs.drawings": "Bản vẽ",
+    "ui.first_angle": "Góc chiếu thứ nhất",
+    "ui.projection_of_new_drawings": "Phép chiếu của bản vẽ mới",
+    "ui.third_angle": "Góc chiếu thứ ba"
+  }
+}

assets/locales/zh.json

@@ -833,6 +833,8 @@
   "cmd.appearance_pick_up": "拾取外观",
   "cmd.appearance_replace": "替换外观",
   "cmd.assembly_bom": "物料清单",
+  "cmd.assembly_bom_item_set": "更改项目编号",
+  "cmd.assembly_bom_renumber": "重新编号项目",
   "cmd.assembly_mass_properties": "质量属性",
   "cmd.body.print_face": "打印底面",
   "cmd.body_rename": "重命名实体",
@@ -932,6 +934,36 @@
   "cmd.document_metadata_set": "更改设计属性",
   "cmd.document_revision": "设计版本号",
   "cmd.document_units": "更改设计单位",
+  "cmd.drawing_balloon_add": "添加零件序号",
+  "cmd.drawing_balloon_edit": "编辑零件序号",
+  "cmd.drawing_balloon_inspect": "检查零件序号",
+  "cmd.drawing_close": "关闭绘图",
+  "cmd.drawing_create": "创建绘图",
+  "cmd.drawing_delete": "删除绘图",
+  "cmd.drawing_dimension_add": "添加绘图尺寸",
+  "cmd.drawing_dimension_edit": "编辑绘图尺寸",
+  "cmd.drawing_dimension_inspect": "检查绘图尺寸",
+  "cmd.drawing_export": "导出图纸",
+  "cmd.drawing_inspect": "检查绘图",
+  "cmd.drawing_list": "列出绘图",
+  "cmd.drawing_open": "打开绘图",
+  "cmd.drawing_properties": "绘图属性",
+  "cmd.drawing_properties_remove": "删除绘图属性",
+  "cmd.drawing_properties_set": "更改绘图属性",
+  "cmd.drawing_revision_add": "添加版本",
+  "cmd.drawing_revision_delete": "删除版本",
+  "cmd.drawing_revision_edit": "编辑版本",
+  "cmd.drawing_scene": "绘制图纸",
+  "cmd.drawing_set": "绘图设置",
+  "cmd.drawing_sheet_add": "添加图纸",
+  "cmd.drawing_sheet_delete": "删除图纸",
+  "cmd.drawing_sheet_reorder": "重新排列图纸",
+  "cmd.drawing_sheet_set": "图纸设置",
+  "cmd.drawing_view_copy_to_sheet": "将视图复制到图纸",
+  "cmd.drawing_view_edit": "编辑绘图视图",
+  "cmd.drawing_view_inspect": "检查绘图视图",
+  "cmd.drawing_view_move_to_sheet": "将视图移至图纸",
+  "cmd.drawing_view_snapshot": "绘图视图快照",
   "cmd.edit_checkpoint": "检查点",
   "cmd.edit_repeat": "重复上一个命令",
   "cmd.edit_restore_checkpoint": "恢复检查点",
@@ -1029,6 +1061,7 @@
   "cmd.motion_trace_edit": "编辑运动轨迹",
   "cmd.motion_trace_keep": "保留运动轨迹",
   "cmd.occurrence_align": "对齐实例",
+  "cmd.occurrence_bom_type": "物料清单类型",
   "cmd.occurrence_copy": "粘贴（实例）",
   "cmd.occurrence_drag": "拖动实例",
   "cmd.occurrence_ground": "固定",
@@ -2345,6 +2378,7 @@
   "prefs.dimension_values_view": "在视图中",
   "prefs.dimension_values_window": "在窗口中",
   "prefs.display": "显示",
+  "prefs.drawings": "绘图",
   "prefs.edges": "边缘与着色",
   "prefs.extend": "扩展",
   "prefs.extra_navigation": "在空白处按住Ctrl并用鼠标左键拖动可旋转；按住空格键可平移。",
@@ -4981,6 +5015,7 @@
   "ui.fine": "精细",
   "ui.finest": "最精细",
   "ui.finish_sketch": "完成草图",
+  "ui.first_angle": "第一角投影",
   "ui.fit": "适合",
   "ui.fix_unfix": "固定/取消固定",
   "ui.flat": "平面",
@@ -5285,6 +5320,7 @@
   "ui.profiles": "轮廓",
   "ui.project": "投影",
   "ui.project_face_edges_sketch": "将面的边投影到新草图",
+  "ui.projection_of_new_drawings": "新绘图的投影法",
   "ui.properties": "属性",
   "ui.properties.copy_matrix": "复制矩阵",
   "ui.properties.first_moments": "一阶矩",
@@ -5470,6 +5506,7 @@
   "ui.text": "文本",
   "ui.theme": "主题",
   "ui.thickness": "厚度",
+  "ui.third_angle": "第三角投影",
   "ui.thread": "螺纹",
   "ui.tie_ends": "约束",
   "ui.tie_ends_tip": "约束全部未约束端点",

attribution/pending/drawing-web-fonts.md

@@ -0,0 +1,8 @@
+| assets/fonts/noto-sans-arabic/NotoSansArabic-Regular.ttf | The Noto Project Authors (Noto Sans Arabic 2.013, hinted) | https://github.com/notofonts/notofonts.github.io (fonts/NotoSansArabic/hinted/ttf), unmodified; licence text in assets/fonts/noto-sans-arabic/OFL.txt; the web app's font for a drawing's Arabic text | SIL OFL 1.1 |
+| assets/fonts/noto-sans-arabic/OFL.txt | The Noto Project Authors | Unmodified accompanying font licence (https://github.com/notofonts/arabic) | SIL OFL 1.1 |
+| assets/fonts/noto-sans-kr/NotoSansKR-Regular.otf | Adobe (Noto Sans KR 2.004, Noto Sans CJK subset) | https://github.com/notofonts/noto-cjk (Sans/SubsetOTF/KR), unmodified; licence text in assets/fonts/noto-sans-kr/OFL.txt; the web app's font for a drawing's Korean text | SIL OFL 1.1 |
+| assets/fonts/noto-sans-kr/OFL.txt | Adobe | Unmodified accompanying font licence (https://github.com/notofonts/noto-cjk, Sans/LICENSE) | SIL OFL 1.1 |
+| assets/fonts/noto-sans-sc/NotoSansSC-Regular.otf | Adobe (Noto Sans SC 2.004, Noto Sans CJK subset) | https://github.com/notofonts/noto-cjk (Sans/SubsetOTF/SC), unmodified; licence text in assets/fonts/noto-sans-sc/OFL.txt; the web app's font for a drawing's simplified Chinese text | SIL OFL 1.1 |
+| assets/fonts/noto-sans-sc/OFL.txt | Adobe | Unmodified accompanying font licence (https://github.com/notofonts/noto-cjk, Sans/LICENSE) | SIL OFL 1.1 |
+| assets/fonts/noto-sans-tc/NotoSansTC-Regular.otf | Adobe (Noto Sans TC 2.004, Noto Sans CJK subset) | https://github.com/notofonts/noto-cjk (Sans/SubsetOTF/TC), unmodified; licence text in assets/fonts/noto-sans-tc/OFL.txt; the web app's font for a drawing's traditional Chinese text | SIL OFL 1.1 |
+| assets/fonts/noto-sans-tc/OFL.txt | Adobe | Unmodified accompanying font licence (https://github.com/notofonts/noto-cjk, Sans/LICENSE) | SIL OFL 1.1 |

attribution/pending/drawing-workspace-ui.md

@@ -0,0 +1,22 @@
+| assets/icons/ui/design/svg/model/drawing_base_view.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_projected_view.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_section_view.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_detail_view.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_align_views.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_image.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_dimension.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_hole_callout.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_leader.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_datum.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_centre_mark.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_align_annotations.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_space_annotations.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_parts_list.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_balloon.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_edit_table.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_revision_table.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_update.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_check.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_revision.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_print.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |
+| assets/icons/ui/design/svg/model/drawing_resources.svg | SolidCraft contributors | original icon master (64 grid) | MIT OR Apache-2.0 |

crates/doc/src/assembly.rs

@@ -29,6 +29,18 @@ pub fn mat_mul(a: &Mat, b: &Mat) -> Mat {
     r
 }
 
+/// How much `m` scales a volume: the size of the determinant of its linear part (1 for a rigid
+/// placement).
+pub fn mat_volume_scale(m: &Mat) -> f64 {
+    let c = |i: usize| m.get(i).map_or(Vec3::ZERO, |col| Vec3::new(col[0], col[1], col[2]));
+    c(0).dot(c(1).cross(c(2))).abs()
+}
+
+/// Why an assembly too large to walk whole is refused.
+pub(crate) fn too_many_placements() -> crate::DocError {
+    crate::DocError::Invalid(format!("the assembly is deeper than {MAX_PLACEMENT_DEPTH} levels or has more than {MAX_PLACEMENTS} placements"))
+}
+
 pub fn apply_point(m: &Mat, p: Vec3) -> Vec3 {
     Vec3::new(
         m[0][0] * p.x + m[1][0] * p.y + m[2][0] * p.z + m[3][0],
@@ -45,6 +57,11 @@ pub fn apply_vector(m: &Mat, v: Vec3) -> Vec3 {
     )
 }
 
+/// `p` carried by `m`: `None` when `m` flattens it.
+pub fn map_plane(m: &Mat, p: &Plane) -> Option<Plane> {
+    Plane::new(apply_point(m, p.origin), apply_vector(m, p.x), apply_vector(m, p.y))
+}
+
 pub fn is_identity(m: &Mat) -> bool {
     m.iter().flatten().zip(IDENTITY.iter().flatten()).all(|(a, b)| (a - b).abs() < 1e-12)
 }
@@ -136,6 +153,10 @@ pub struct Occurrence {
     /// Grounded occurrences don't move.
     #[serde(default)]
     pub grounded: bool,
+    /// How this occurrence counts in the bill of materials, in place of its component's type
+    /// (`None`: as its component).
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub bom_type: Option<BomType>,
 }
 
 fn identity() -> Mat {
@@ -144,7 +165,8 @@ fn identity() -> Mat {
 
 /// How a component counts in the bill of materials of an assembly it is placed in. It is a part
 /// property (the `bom_type` key of the component's [`Metadata`](crate::Metadata)); a component
-/// without one is [`BomType::Normal`].
+/// without one is [`BomType::Normal`]. One occurrence can count as another type
+/// ([`Occurrence::bom_type`]).
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub enum BomType {
@@ -188,21 +210,16 @@ impl BomType {
 pub const MAX_PLACEMENT_DEPTH: usize = 64;
 pub const MAX_PLACEMENTS: usize = 100_000;
 
-fn map_plane(m: &Mat, p: &Plane) -> Plane {
-    let (o, x, y) = (apply_point(m, p.origin), apply_vector(m, p.x), apply_vector(m, p.y));
-    Plane::new(o, x, y).unwrap_or(*p)
-}
-
 fn map_plane_ref(m: &Mat, p: &mut PlaneRef) {
     match p {
-        PlaneRef::Custom { plane } => *plane = map_plane(m, plane),
+        PlaneRef::Custom { plane } => *plane = map_plane(m, plane).unwrap_or(*plane),
         PlaneRef::Placed { origin, x_dir, y_dir } => {
             map_point_expr(m, origin);
             *x_dir = apply_vector(m, *x_dir);
             *y_dir = apply_vector(m, *y_dir);
         }
         PlaneRef::Face { plane, at, .. } => {
-            *plane = map_plane(m, plane);
+            *plane = map_plane(m, plane).unwrap_or(*plane);
             *at = apply_point(m, *at);
         }
         PlaneRef::Offset { base, .. } | PlaneRef::Flipped { base, .. } => map_plane_ref(m, base),
@@ -324,6 +341,22 @@ impl Document {
         self.occurrences.iter().find(|o| o.component == component)
     }
 
+    /// The bill of materials type each occurrence counts as, in the order of `occurrences`: its
+    /// own ([`Occurrence::bom_type`]), else its component's. Components are looked up once.
+    pub fn occurrence_bom_types(&self) -> Vec<BomType> {
+        let types: std::collections::HashMap<u64, BomType> =
+            self.components.iter().map(|c| (c.id, c.metadata.bom_type())).filter(|(_, t)| *t != BomType::Normal).collect();
+        self.occurrences.iter().map(|o| o.bom_type.or_else(|| types.get(&o.component).copied()).unwrap_or_default()).collect()
+    }
+
+    /// The occurrences that count as reference ([`Document::occurrence_bom_types`]). A body placed
+    /// through any of them is a reference part: the bill of materials counts nothing inside a
+    /// reference, and a drawing draws all of it as reference.
+    pub fn reference_occurrences(&self) -> std::collections::HashSet<u64> {
+        let types = self.occurrences.iter().zip(self.occurrence_bom_types());
+        types.filter(|(_, bom_type)| *bom_type == BomType::Reference).map(|(o, _)| o.id).collect()
+    }
+
     /// World transform of a component's frame (through its first occurrence and its parents').
     pub fn component_transform(&self, component: u64) -> Mat {
         transform_through(component, |c| self.occurrence_of(c))
@@ -374,6 +407,45 @@ impl Document {
         out
     }
 
+    /// Whether [`Document::placements`] reaches every placement. Its walk stops at
+    /// [`MAX_PLACEMENTS`], and a branch past [`MAX_PLACEMENT_DEPTH`] levels, so a placement it
+    /// holds may have occurrences it never walked; the walk is whole when none does.
+    pub fn placements_complete(&self) -> bool {
+        let mut children = std::collections::HashMap::<u64, usize>::new();
+        for o in &self.occurrences {
+            *children.entry(o.parent).or_default() += 1;
+        }
+        let walk = self.placements();
+        let reached = walk.iter().fold(0usize, |n, (c, _, _)| n.saturating_add(children.get(c).copied().unwrap_or(0)));
+        walk.len() == reached.saturating_add(1)
+    }
+
+    /// The placement `path` of `component` at `world`, and every placement below it: (component,
+    /// occurrence path ids, world transform), the start first. Unlike [`Self::placements`], which
+    /// stops a branch where the display does, a larger assembly is refused, never walked in part:
+    /// for totals that must cover all of it (physical properties).
+    pub fn placements_below(&self, component: u64, path: &[u64], world: Mat) -> crate::Result<Vec<(u64, Vec<u64>, Mat)>> {
+        let mut children: std::collections::HashMap<u64, Vec<&Occurrence>> = std::collections::HashMap::new();
+        for o in &self.occurrences {
+            children.entry(o.parent).or_default().push(o);
+        }
+        let mut out = vec![(component, path.to_vec(), world)];
+        let mut stack = vec![(component, path.to_vec(), world)];
+        while let Some((parent, path, world)) = stack.pop() {
+            for o in children.get(&parent).into_iter().flatten() {
+                if path.len() >= MAX_PLACEMENT_DEPTH || out.len() > MAX_PLACEMENTS {
+                    return Err(too_many_placements());
+                }
+                let mut child = path.clone();
+                child.push(o.id);
+                let w = mat_mul(&world, &o.transform);
+                out.push((o.component, child.clone(), w));
+                stack.push((o.component, child, w));
+            }
+        }
+        Ok(out)
+    }
+
     /// Every body as the world shows it: its world name ("Body1", or "Body1 (Occ:2)" for a
     /// further instance), its component, the occurrence path, and the transform from the frame
     /// its geometry is in to the world.
@@ -440,6 +512,21 @@ impl Document {
         false
     }
 
+    /// The virtual components that hold something, by id: a feature (a sketch, a body's, a moved
+    /// body's) or a placed component. A virtual component holds nothing ([`crate::metadata::VIRTUAL`]):
+    /// the engine refuses any change that puts something in one.
+    pub fn virtual_holding(&self) -> Vec<u64> {
+        let virtuals: std::collections::HashSet<u64> = self.components.iter().filter(|c| c.metadata.is_virtual()).map(|c| c.id).collect();
+        if virtuals.is_empty() {
+            return Vec::new();
+        }
+        let mut held: Vec<u64> =
+            self.features.iter().map(|f| f.component).chain(self.occurrences.iter().map(|o| o.parent)).filter(|id| virtuals.contains(id)).collect();
+        held.sort_unstable();
+        held.dedup();
+        held
+    }
+
     /// Is `c` (or one of its ancestors) marked out of the History bar (#10393)? The root (0)
     /// never is: its own features always show.
     pub fn component_history_hidden(&self, mut c: u64) -> bool {
@@ -503,7 +590,7 @@ impl Document {
             !self.occurrences.iter().any(|o| o.name == name)
         };
         let k = std::iter::once(next).chain(1..).find(free).unwrap_or(next);
-        self.occurrences.push(crate::Occurrence { id, component, parent, name: format!("{cname}:{k}"), transform, grounded: false });
+        self.occurrences.push(crate::Occurrence { id, component, parent, name: format!("{cname}:{k}"), transform, grounded: false, bom_type: None });
         Ok(id)
     }
 }

crates/doc/src/bom.rs

@@ -0,0 +1,964 @@
+//! The bill of materials of an assembly (the design, or one component's definition): the rows a
+//! bill of materials view lists, typed. `assembly.bom`'s JSON and CSV and the Bill of Materials
+//! window present these rows; parts lists, item numbers and balloons are to read them too.
+//!
+//! [`list`] walks the placements below the assembly once. One rule (`classify`) decides for each
+//! placement whether it is counted in a row, how what it holds is walked and what its row stands
+//! for when weighed, from the bill of materials type it counts as (its occurrence's, else its
+//! component's), the view and the component's shape. One budget of [`MAX_PLACEMENTS`] placements
+//! and [`MAX_PLACEMENT_DEPTH`] levels covers the whole list, folded parts' contents included: a
+//! larger assembly is refused, never listed in part.
+//!
+//! A row is named by its `RowKey`: the rows it is listed under and its lowest member (a
+//! component and the type it counts as there), however its part number or contents read. Its
+//! mass is what one of its parts weighs as the row stands for it (`Holds`), so the rows of any
+//! list add up to the assembly once. The keys, what rows stand for and their members stay inside
+//! this crate: a balloon reads its row's item ([`Bom::item_of`]), and item numbers are saved by key ([`numbers`]). Placements are rigid, so
+//! each definition is weighed once however often it is placed, and kept in the [`Tree`] for every list made from it. The
+//! assembly's own mass is weighed the same way, never added up from rows: a row whose definitions
+//! weigh differently has none.
+//!
+//! Materials are bodies' (`material.assign`): a row names the materials of the bodies it stands for,
+//! and a row that stands for an assembly names one only when everything in it shares it. A static
+//! material typed in for a component ([`metadata::MATERIAL`](crate::metadata::MATERIAL)) is what
+//! its rows say instead, in every view and at every level ([`Row::statics`]), and what it stands
+//! for in the one material an assembly around it shares: the bill of materials says one thing
+//! about the part everywhere. It only names: mass still comes from the bodies.
+//!
+//! A row's [`Quantity`] adds up what each of its placements means ([`quantity`]): each definition's
+//! quantity is evaluated once for every list made from the [`Tree`].
+
+use std::cmp::Ordering;
+use std::collections::{BTreeMap, HashMap};
+
+use serde::{Deserialize, Serialize};
+
+use crate::{BomType, Component, DocError, Document, MAX_PLACEMENT_DEPTH, MAX_PLACEMENTS, ModelBody, ModelState, Result};
+
+mod numbers;
+mod quantity;
+
+pub use numbers::{ItemNumber, ItemNumbers, MAX_ITEM, Numbering, Order, number, record};
+pub use quantity::{Amount, Quantity, Uncounted, amount};
+
+/// A bill of materials view, saved by the word commands use for it.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub enum View {
+    /// Parts only: every part at any depth, counted through its subassemblies.
+    #[default]
+    #[serde(rename = "flat")]
+    PartsOnly,
+    /// Structured, first level: the assembly's direct contents, a subassembly as one row.
+    #[serde(rename = "top")]
+    FirstLevel,
+    /// Structured, all levels: the assembly's direct contents, each subassembly a row with its own
+    /// contents listed under it, to any depth (1, 1.1, 1.1.1).
+    #[serde(rename = "all")]
+    AllLevels,
+}
+
+impl View {
+    /// Every view, in the order commands and documentation list them.
+    pub const ALL: [View; 3] = [View::PartsOnly, View::FirstLevel, View::AllLevels];
+
+    /// The word commands use (`assembly.bom`'s `levels`).
+    pub fn as_str(self) -> &'static str {
+        match self {
+            View::PartsOnly => "flat",
+            View::FirstLevel => "top",
+            View::AllLevels => "all",
+        }
+    }
+
+    /// The view a word names, if it names one.
+    pub fn parse(word: &str) -> Option<View> {
+        View::ALL.into_iter().find(|v| v.as_str() == word)
+    }
+}
+
+/// What one row gathers.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum Group {
+    /// The definitions that share a part number; a definition without one is a row of its own.
+    #[default]
+    PartNumber,
+    /// One definition.
+    Definition,
+}
+
+impl Group {
+    /// Every grouping, in the order commands and documentation list them.
+    pub const ALL: [Group; 2] = [Group::PartNumber, Group::Definition];
+
+    /// The word commands use (`assembly.bom`'s `group_by`).
+    pub fn as_str(self) -> &'static str {
+        match self {
+            Group::PartNumber => "part_number",
+            Group::Definition => "definition",
+        }
+    }
+
+    /// The grouping a word names, if it names one.
+    pub fn parse(word: &str) -> Option<Group> {
+        Group::ALL.into_iter().find(|g| g.as_str() == word)
+    }
+}
+
+/// What a bill of materials lists. The default is the design's parts only, by part number.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub struct Request {
+    /// The assembly listed: a component, or 0 for the design.
+    pub source: u64,
+    pub view: View,
+    pub group: Group,
+    /// A normal part with a part number is one row, and what it holds is listed under it as its
+    /// children (as parts only lists them) instead of as rows of their own.
+    pub fold: bool,
+    /// Weigh each row and the assembly: every part is measured, so it is asked for.
+    pub mass: bool,
+    /// In all levels, what a purchased part holds is listed under it too (it is still one row,
+    /// weighed whole).
+    pub purchased_contents: bool,
+}
+
+/// A component as one placement counts: its id and the bill of materials type it counts as there.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct Member {
+    pub component: u64,
+    pub bom_type: BomType,
+}
+
+/// A row's identity: the key members of the rows it is listed under (outermost first; none at the
+/// top), and its own lowest member. It doesn't change with the row's part number or contents, so
+/// item numbers, overrides and balloons can follow the row through those edits.
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub(crate) struct RowKey {
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub(crate) parents: Vec<Member>,
+    pub(crate) member: Member,
+}
+
+/// What one of a row's parts stands for when it is weighed, so that the rows of any list add up
+/// to the assembly once.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub(crate) enum Holds {
+    /// Its own bodies and everything placed inside it.
+    All,
+    /// Its own bodies alone: what it holds is listed beside it.
+    Own,
+    /// Everything but its purchased parts, which are listed beside it (an inseparable part in
+    /// parts only).
+    AllButPurchased,
+}
+
+/// What one of a row's parts weighs, or the assembly.
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
+pub enum Mass {
+    /// Not asked for ([`Request::mass`]).
+    #[default]
+    NotAsked,
+    Grams(f64),
+    Unknown(Unknown),
+}
+
+/// Why a mass isn't known.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Unknown {
+    /// Nothing in it has a body.
+    NothingToWeigh,
+    /// A body in it can't be measured, or measures inside out (a negative volume).
+    Unmeasurable,
+    /// The definitions the row gathers (one part number) weigh differently.
+    Differs,
+}
+
+/// A value of a row typed in by hand for its component, in place of the one worked out.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Static {
+    /// [`Row::materials`], from [`metadata::MATERIAL`](crate::metadata::MATERIAL).
+    Material,
+}
+
+impl Static {
+    /// The part property it is kept under, and its name in `assembly.bom`'s rows.
+    pub fn key(self) -> &'static str {
+        match self {
+            Static::Material => crate::metadata::MATERIAL,
+        }
+    }
+}
+
+/// One row of a bill of materials view.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Row {
+    pub(crate) key: RowKey,
+    /// Its item number among the rows it is listed with: the one saved for it, else its position
+    /// from 1 (the view not numbered yet) or the next number after the saved ones ([`numbers`]).
+    pub item: u32,
+    /// Its item number isn't saved yet.
+    pub provisional: bool,
+    /// Its item number is locked: a renumber keeps it.
+    pub locked: bool,
+    /// Another row listed with it has the same item number.
+    pub duplicate: bool,
+    pub bom_type: BomType,
+    /// What one of its parts stands for when weighed.
+    pub(crate) stands_for: Holds,
+    /// The definitions it gathers, by id (ascending), and their names, each once.
+    pub components: Vec<u64>,
+    pub names: Vec<String>,
+    /// Its part properties: its first definition's part number (the one it gathers by), and the
+    /// first description and revision its definitions give.
+    pub part_number: String,
+    pub description: String,
+    pub revision: String,
+    /// The definitions' free properties; where several give one name, the first's.
+    pub properties: BTreeMap<String, String>,
+    /// The physical materials of what one of its parts stands for, each once, in body order: a
+    /// part's own bodies'. A row that stands for an assembly (something placed inside it is weighed
+    /// with it) shows the one material all of that shares, else none. A static material replaces
+    /// them.
+    pub materials: Vec<String>,
+    /// Its values typed in by hand ([`Static`]). Where its definitions give different ones, the
+    /// first's that gives one wins, as with its description.
+    pub statics: Vec<Static>,
+    /// How many are listed: in all, and in one of the row it is listed under (the assembly at the
+    /// top).
+    pub count: u64,
+    pub each: u64,
+    /// What its placements add up to, when its definitions have quantities.
+    pub quantity: Quantity,
+    /// The placements it counts, by occurrence path from the assembly listed, in path order;
+    /// empty unless the list was made with them (`list_with`).
+    pub(crate) members: Vec<Vec<u64>>,
+    pub mass: Mass,
+    /// What one of it holds, listed under it: a folded part's contents as parts only lists them,
+    /// or in all levels a subassembly's own rows.
+    pub children: Vec<Row>,
+}
+
+/// The assembly as a whole.
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
+pub struct Total {
+    /// Every placement listed, children included.
+    pub occurrences: u64,
+    /// Its own bodies and all it holds but references, weighed from the design (with the rows'
+    /// measurements), not added up from rows.
+    pub mass: Mass,
+}
+
+/// The rows of one bill of materials view.
+#[derive(Clone, Debug, Default, PartialEq)]
+pub struct Bom {
+    /// The assembly listed: a component, or 0 for the design.
+    pub source: u64,
+    /// By part number, rows without one after them by name, one part's rows by type (`list_order`);
+    /// each row's children likewise. In a numbered view, by item number.
+    pub rows: Vec<Row>,
+    pub total: Total,
+    /// Its item numbers are saved: it has been numbered ([`ItemNumbers`]).
+    pub numbered: bool,
+    /// Each member path, and where its row is (its position among the rows, then among each one's
+    /// children): `row_of` reads it. Empty unless the list was made with its members.
+    index: HashMap<Vec<u64>, Vec<usize>>,
+}
+
+/// Why a placement is counted in no row of a list.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Unlisted {
+    /// No placement below the assembly listed has that path.
+    NotFound,
+    /// It counts as a reference, or is inside one: no bill of materials counts it.
+    Reference,
+    /// It has no row of its own and isn't inside one: a phantom without bodies, or in parts only
+    /// a subassembly listed through its parts (the assembly listed, an empty path, is none either).
+    NoRow,
+}
+
+impl Bom {
+    /// Every row, each followed by the rows listed under it (1, 1.1, 1.2, 2…), with its item
+    /// numbers from the top (`[1, 2]` reads 1.2).
+    pub fn rows_deep(&self) -> Vec<(Vec<u32>, &Row)> {
+        let mut out = Vec::new();
+        let mut stack: Vec<(Vec<u32>, &Row)> = self.rows.iter().rev().map(|r| (vec![r.item], r)).collect();
+        while let Some((item, row)) = stack.pop() {
+            for child in row.children.iter().rev() {
+                let mut under = item.clone();
+                under.push(child.item);
+                stack.push((under, child));
+            }
+            out.push((item, row));
+        }
+        out
+    }
+
+    /// The row a placement is counted in, by its occurrence path from the assembly listed: the row
+    /// that lists it, else the row of the part it is inside (a nut inside a purchased bolt is
+    /// counted in the bolt's). `tree` is the one the list was made from, with its members
+    /// (`list_with`).
+    pub(crate) fn row_of(&self, tree: &Tree, path: &[u64]) -> std::result::Result<(Vec<u32>, &Row), Unlisted> {
+        if path.len() > MAX_PLACEMENT_DEPTH {
+            return Err(Unlisted::NotFound);
+        }
+        let mut component = self.source;
+        for id in path {
+            let placed = tree.contents(component).iter().find(|p| p.occurrence == *id).ok_or(Unlisted::NotFound)?;
+            if placed.member.bom_type == BomType::Reference {
+                return Err(Unlisted::Reference);
+            }
+            component = placed.member.component;
+        }
+        // Each placement is in one row or none, so the longest member path it starts with is its row's.
+        let at = (1..=path.len()).rev().find_map(|n| path.get(..n).and_then(|start| self.index.get(start)));
+        at.and_then(|at| self.row_at(at)).ok_or(Unlisted::NoRow)
+    }
+
+    /// The row at `at` (its position among the rows, then among each one's children), with its item
+    /// numbers from the top.
+    fn row_at(&self, at: &[usize]) -> Option<(Vec<u32>, &Row)> {
+        let (first, rest) = at.split_first()?;
+        let mut row = self.rows.get(*first)?;
+        let mut item = vec![row.item];
+        for &i in rest {
+            row = row.children.get(i)?;
+            item.push(row.item);
+        }
+        Some((item, row))
+    }
+
+    /// The item ("1.2") of the row a placement is counted in, by its occurrence path from the top of
+    /// the design: a balloon's, which is cut to start below the assembly listed. A path that doesn't
+    /// run through that assembly is [`Unlisted::NotFound`]; through one of its placements, whichever,
+    /// it reads the same row. `tree` is as for `row_of`.
+    pub fn item_of(&self, tree: &Tree, path: &[u64]) -> std::result::Result<String, Unlisted> {
+        let below = tree.below(self.source, path).ok_or(Unlisted::NotFound)?;
+        self.row_of(tree, below).map(|(item, _)| item_text(&item))
+    }
+
+    /// Where each member's row is, for `row_of`.
+    fn index_members(&mut self) {
+        let mut index = HashMap::new();
+        let mut stack: Vec<(Vec<usize>, &Row)> = self.rows.iter().enumerate().map(|(i, r)| (vec![i], r)).collect();
+        while let Some((at, row)) = stack.pop() {
+            for member in &row.members {
+                index.insert(member.clone(), at.clone());
+            }
+            for (i, child) in row.children.iter().enumerate() {
+                let mut under = at.clone();
+                under.push(i);
+                stack.push((under, child));
+            }
+        }
+        self.index = index;
+    }
+}
+
+/// Item numbers as one reads them: `[1, 2]` is "1.2".
+pub fn item_text(item: &[u32]) -> String {
+    item.iter().map(u32::to_string).collect::<Vec<_>>().join(".")
+}
+
+/// The design's structure as bills of materials read it, looked up once, and what each
+/// definition weighs, measured once for every list made from it. It reads one state of the
+/// design: make another after a change.
+pub struct Tree<'a> {
+    doc: &'a Document,
+    /// What each component places (by its id; 0 is the root), in occurrence order.
+    children: HashMap<u64, Vec<Placed>>,
+    components: HashMap<u64, &'a Component>,
+    /// Each component's own bodies, in body order; a component that owns none isn't here.
+    bodies: HashMap<u64, Vec<&'a ModelBody>>,
+    /// What one of each definition weighs, by what it stands for.
+    weighed: BTreeMap<(u64, Holds), Weighed>,
+    /// The materials of what one of each definition stands for, each once, in body order.
+    made_of: BTreeMap<(u64, Holds), Vec<String>>,
+    /// What one placement of each definition with a quantity counts: `None` when it doesn't
+    /// evaluate.
+    amounts: HashMap<u64, Option<Amount>>,
+}
+
+/// One occurrence: its id, and the component it places with the type it counts as there.
+#[derive(Clone, Copy, Debug)]
+struct Placed {
+    occurrence: u64,
+    member: Member,
+}
+
+/// What one of a component weighs: grams, and how many bodies that is (none: nothing to weigh).
+/// `None` when a body in it can't be measured, or measures inside out.
+type Weighed = Option<(f64, usize)>;
+
+impl<'a> Tree<'a> {
+    /// The structure of `doc` with the bodies of `state`, its evaluated model.
+    pub fn new(doc: &'a Document, state: &'a ModelState) -> Tree<'a> {
+        let mut children: HashMap<u64, Vec<Placed>> = HashMap::new();
+        for (o, bom_type) in doc.occurrences.iter().zip(doc.occurrence_bom_types()) {
+            children.entry(o.parent).or_default().push(Placed { occurrence: o.id, member: Member { component: o.component, bom_type } });
+        }
+        let mut components: HashMap<u64, &Component> = HashMap::new();
+        for c in &doc.components {
+            components.entry(c.id).or_insert(c);
+        }
+        let mut bodies: HashMap<u64, Vec<&ModelBody>> = HashMap::new();
+        for (body, owner) in state.bodies.iter().zip(doc.model_body_components(state)) {
+            bodies.entry(owner).or_default().push(body);
+        }
+        let values = std::cell::OnceCell::new();
+        let amounts = components.values().filter_map(|c| Some((c.id, quantity::amount_in(doc, &values, c.metadata.bom_quantity()?).ok()))).collect();
+        Tree { doc, children, components, bodies, weighed: BTreeMap::new(), made_of: BTreeMap::new(), amounts }
+    }
+
+    /// What a component places.
+    fn contents(&self, id: u64) -> &[Placed] {
+        self.children.get(&id).map_or(&[], Vec::as_slice)
+    }
+
+    /// What of `path`, from the top of the design, runs below `source`'s first placement on it.
+    fn below<'p>(&self, source: u64, path: &'p [u64]) -> Option<&'p [u64]> {
+        if source == 0 {
+            return Some(path);
+        }
+        let mut component = 0;
+        for (i, id) in path.iter().enumerate() {
+            component = self.contents(component).iter().find(|p| p.occurrence == *id)?.member.component;
+            if component == source {
+                return path.get(i + 1..);
+            }
+        }
+        None
+    }
+
+    /// The components placed in `id` whose parts are part of what `id` stands for as `holds` says
+    /// (see `adds`), one for each placement, with the type each counts as there.
+    fn adding(&self, id: u64, holds: Holds) -> Vec<Member> {
+        self.contents(id).iter().filter(|p| adds(holds, p.member.bom_type)).map(|p| p.member).collect()
+    }
+
+    /// The static material typed in for a component, if any.
+    fn static_material(&self, id: u64) -> Option<&'a str> {
+        self.components.get(&id).and_then(|c| c.metadata.material())
+    }
+
+    fn own_bodies(&self, id: u64) -> &[&'a ModelBody] {
+        self.bodies.get(&id).map_or(&[], Vec::as_slice)
+    }
+
+    /// What a row of `member` gathers by: its part number when `group` asks for that and it has
+    /// one, else its definition. `None` for a damaged file's occurrence of a component that isn't
+    /// there, which has no row.
+    fn part(&self, member: Member, group: Group) -> Option<Part<'a>> {
+        let c: &'a Component = self.components.get(&member.component)?;
+        Some(match c.metadata.part_number() {
+            Some(pn) if group == Group::PartNumber => Part::Number(pn),
+            _ => Part::Definition(member.component),
+        })
+    }
+
+    /// The rows of one level: the placements `at` (positions in `entries`), gathered as `group`
+    /// says, listed under the rows `parents` names, `per` of them in all (1 for the assembly).
+    /// The rows under these are gathered as `under` says.
+    #[allow(clippy::too_many_arguments)]
+    fn level(&self, listing: &Listing, paths: &mut [Vec<u64>], at: &[usize], group: Group, under: Group, parents: &[Member], per: u64) -> Vec<Row> {
+        let mut grouped: BTreeMap<GroupKey<'a>, Vec<usize>> = BTreeMap::new();
+        for &i in at {
+            let Some(entry) = listing.entries.get(i) else { continue };
+            let Some(part) = self.part(entry.member, group) else { continue };
+            let kit = listing.kits.get(i).copied().unwrap_or_default();
+            grouped.entry(GroupKey { part, bom_type: entry.member.bom_type, kit }).or_default().push(i);
+        }
+        let mut rows: Vec<Row> = grouped.values().filter_map(|members| self.row(listing, paths, members, under, parents, per)).collect();
+        rows.sort_by(list_order);
+        for (item, row) in (1..).zip(&mut rows) {
+            row.item = item;
+        }
+        rows
+    }
+
+    /// Each entry's kit, as a number: what it holds as its row's children read it, to any depth.
+    /// Two entries have the same kit when what they hold is the same parts (by part number, else
+    /// definition), counted as the same types, each holding the same again all the way down. One
+    /// pass from the last entry back: an entry's children come after it, so theirs are known first.
+    fn kits(&self, entries: &[Entry], kids: &[Vec<usize>]) -> Vec<u32> {
+        let mut kit_ids: HashMap<Vec<u32>, u32> = HashMap::new();
+        let mut placed_ids: HashMap<(Option<Part<'a>>, BomType, u32), u32> = HashMap::new();
+        // Each entry as a child reads: its part, its type and its own kit.
+        let mut placed = vec![0u32; entries.len()];
+        let mut kits = vec![0u32; entries.len()];
+        for (i, entry) in entries.iter().enumerate().rev() {
+            let mut held: Vec<u32> = kids.get(i).into_iter().flatten().filter_map(|&k| placed.get(k).copied()).collect();
+            held.sort_unstable();
+            let next = kit_ids.len() as u32;
+            let kit = *kit_ids.entry(held).or_insert(next);
+            let next = placed_ids.len() as u32;
+            let key = (self.part(entry.member, Group::PartNumber), entry.member.bom_type, kit);
+            if let (Some(k), Some(p)) = (kits.get_mut(i), placed.get_mut(i)) {
+                *k = kit;
+                *p = *placed_ids.entry(key).or_insert(next);
+            }
+        }
+        kits
+    }
+
+    /// One row: the placements `members` (positions in `entries`) of one part, type and kit, with
+    /// the rows under it gathered as `under` says. Their `paths` (when the list keeps them) move into
+    /// the row: each placement is in one row.
+    #[allow(clippy::too_many_arguments)]
+    fn row(&self, listing: &Listing, paths: &mut [Vec<u64>], members: &[usize], under: Group, parents: &[Member], per: u64) -> Option<Row> {
+        let listed: Vec<&Entry> = members.iter().filter_map(|&i| listing.entries.get(i)).collect();
+        let first = listed.first()?;
+        let mut components: Vec<u64> = listed.iter().map(|e| e.member.component).collect();
+        components.sort_unstable();
+        components.dedup();
+        let member = Member { component: *components.first()?, bom_type: first.member.bom_type };
+        let count = listed.len() as u64;
+        let mut taken: Vec<Vec<u64>> = members.iter().filter_map(|&i| paths.get_mut(i).map(std::mem::take)).filter(|p| !p.is_empty()).collect();
+        taken.sort_unstable();
+        // What one of it holds is listed under it.
+        let inside: Vec<usize> = members.iter().flat_map(|&i| listing.kids.get(i).into_iter().flatten().copied()).collect();
+        let mut chain = parents.to_vec();
+        chain.push(member);
+        let mut row = Row {
+            key: RowKey { parents: parents.to_vec(), member },
+            item: 0,
+            provisional: true,
+            locked: false,
+            duplicate: false,
+            bom_type: member.bom_type,
+            stands_for: first.holds,
+            // Filled in by `name_materials`, which reads each definition once.
+            materials: Vec::new(),
+            statics: Vec::new(),
+            components,
+            names: Vec::new(),
+            part_number: String::new(),
+            description: String::new(),
+            revision: String::new(),
+            properties: BTreeMap::new(),
+            count,
+            // Rows with different kits are different rows, to any depth, so every part of the parent
+            // row holds as many.
+            each: count / per.max(1),
+            quantity: quantity::add_up(listed.iter().map(|e| self.amounts.get(&e.member.component))),
+            members: taken,
+            mass: Mass::NotAsked,
+            children: self.level(listing, paths, &inside, under, under, &chain, count),
+        };
+        for (i, c) in row.components.iter().filter_map(|id| self.components.get(id)).enumerate() {
+            let m = &c.metadata;
+            if i == 0 {
+                row.part_number = m.part_number().unwrap_or_default().to_string();
+            }
+            if !row.names.contains(&c.name) {
+                row.names.push(c.name.clone());
+            }
+            if row.description.is_empty() {
+                row.description = m.description().unwrap_or_default().to_string();
+            }
+            if row.revision.is_empty() {
+                row.revision = m.revision().unwrap_or_default().to_string();
+            }
+            for (k, v) in &c.properties {
+                row.properties.entry(k.clone()).or_insert_with(|| v.clone());
+            }
+        }
+        Some(row)
+    }
+
+    /// Each row's materials, and its children's (Cameron, 2026-10-23): a part lists its own bodies';
+    /// a row that stands for an assembly shows a material only when everything it stands for
+    /// shares it, so a frame of steel and aluminium parts reads blank and a bought bearing of steel
+    /// parts reads steel. A static material, the first its definitions give, replaces that.
+    fn name_materials(&mut self, rows: &mut [Row]) -> Result<()> {
+        for row in rows {
+            self.name_materials(&mut row.children)?;
+            let typed_in = row.components.iter().find_map(|&id| self.static_material(id));
+            if let Some(material) = typed_in {
+                row.materials = vec![material.to_string()];
+                row.statics.push(Static::Material);
+                continue;
+            }
+            let mut names: Vec<String> = Vec::new();
+            let mut assembly = false;
+            for &c in &row.components {
+                assembly |= row.stands_for != Holds::Own && !self.adding(c, row.stands_for).is_empty();
+                for name in self.made_of(c, row.stands_for, 0)? {
+                    push_once(&mut names, name);
+                }
+            }
+            row.materials = if assembly && names.len() > 1 { Vec::new() } else { names };
+        }
+        Ok(())
+    }
+
+    /// The materials of what one of `id` stands for as `holds` says, each once, in body order: the
+    /// bodies `weigh` weighs. A static material stands for all of a part placed inside it, and for
+    /// a phantom's own bodies only (a phantom's row is its own bodies, so what it holds keeps its
+    /// own). Each definition is read once for each kind of row; `depth` bounds the walk below a
+    /// definition not read yet.
+    fn made_of(&mut self, id: u64, holds: Holds, depth: usize) -> Result<Vec<String>> {
+        if let Some(names) = self.made_of.get(&(id, holds)) {
+            return Ok(names.clone());
+        }
+        if depth > MAX_PLACEMENT_DEPTH {
+            return Err(too_big());
+        }
+        let mut names: Vec<String> = Vec::new();
+        match self.static_material(id) {
+            Some(material) if !self.own_bodies(id).is_empty() => push_once(&mut names, material.to_string()),
+            Some(_) => {}
+            None => {
+                for body in self.own_bodies(id) {
+                    push_once(&mut names, self.doc.body_material(&body.name));
+                }
+            }
+        }
+        if holds != Holds::Own {
+            for child in self.adding(id, holds) {
+                match self.static_material(child.component) {
+                    Some(material) if child.bom_type != BomType::Phantom => push_once(&mut names, material.to_string()),
+                    _ => {
+                        for name in self.made_of(child.component, holds, depth + 1)? {
+                            push_once(&mut names, name);
+                        }
+                    }
+                }
+            }
+        }
+        self.made_of.insert((id, holds), names.clone());
+        Ok(names)
+    }
+
+    /// Each row's mass, and its children's.
+    fn weigh_rows(&mut self, rows: &mut [Row]) -> Result<()> {
+        for row in rows {
+            let weighed = row.components.iter().map(|&c| self.weigh(c, row.stands_for, 0)).collect::<Result<Vec<Weighed>>>()?;
+            row.mass = agree(&weighed);
+            self.weigh_rows(&mut row.children)?;
+        }
+        Ok(())
+    }
+
+    /// One of `id` as `holds` says: its own bodies, and of what is placed inside it everything that
+    /// adds to it (see `adds`). Where a part is placed doesn't change what it weighs, so each
+    /// definition is weighed once for each kind of row and each body measured once. `depth` bounds
+    /// the walk below a definition not weighed yet.
+    fn weigh(&mut self, id: u64, holds: Holds, depth: usize) -> Result<Weighed> {
+        if let Some(&weighed) = self.weighed.get(&(id, holds)) {
+            return Ok(weighed);
+        }
+        if depth > MAX_PLACEMENT_DEPTH {
+            return Err(too_big());
+        }
+        let mut total: Weighed = Some((0.0, 0));
+        if holds == Holds::Own {
+            for body in self.own_bodies(id) {
+                add(&mut total, self.measure(body));
+            }
+        } else {
+            add(&mut total, self.weigh(id, Holds::Own, depth)?);
+            for child in self.adding(id, holds) {
+                add(&mut total, self.weigh(child.component, holds, depth + 1)?);
+            }
+        }
+        let weighed = total.filter(|(grams, _)| grams.is_finite());
+        self.weighed.insert((id, holds), weighed);
+        Ok(weighed)
+    }
+
+    /// What one body weighs, in grams: its volume, measured once for the model
+    /// ([`ModelBody::volume`]), scaled by a body offset as the offset scales what is drawn (a
+    /// damaged file's scaled offset weighs what is drawn).
+    fn measure(&self, body: &ModelBody) -> Weighed {
+        let scale = self.doc.model_body_offset(body).map_or(1.0, crate::mat_volume_scale);
+        // A negative volume (a body inside out) is unknown, never a negative mass.
+        body.volume().map(|v| v * scale).filter(|v| *v >= 0.0).map(|v| (v * self.doc.density(&body.name) / 1000.0, 1))
+    }
+}
+
+/// The order a level lists its rows in until it is numbered: by part number; rows without one
+/// after them, by name; one part's rows by type.
+fn list_order(a: &Row, b: &Row) -> Ordering {
+    (a.part_number.is_empty(), &a.part_number, &a.names, &a.components, a.bom_type).cmp(&(
+        b.part_number.is_empty(),
+        &b.part_number,
+        &b.names,
+        &b.components,
+        b.bom_type,
+    ))
+}
+
+/// What a row gathers by: a part number, borrowed from its definition, or the definition.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+enum Part<'a> {
+    Number(&'a str),
+    Definition(u64),
+}
+
+/// How one row is told from another of its level: what it gathers by, the type its parts count
+/// as, and its kit: what one of them holds as the row's children read it, to any depth (`Tree::kits`;
+/// the same for all that hold nothing listed).
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+struct GroupKey<'a> {
+    part: Part<'a>,
+    bom_type: BomType,
+    kit: u32,
+}
+
+/// The placements a list counts, what each folded or all-levels row holds, and each one's kit.
+struct Listing {
+    entries: Vec<Entry>,
+    /// What each entry holds: the entries listed as its children.
+    kids: Vec<Vec<usize>>,
+    kits: Vec<u32>,
+}
+
+/// How a walk lists what it passes.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+enum Walk {
+    /// What the view lists.
+    Listed,
+    /// Inside an inseparable part in parts only: just its purchased parts, which are listed
+    /// beside it, at any depth.
+    PurchasedOnly,
+}
+
+/// What a placed component is like, as far as listing it goes.
+#[derive(Clone, Copy, Debug, Default)]
+struct Shape {
+    /// It places components of its own.
+    contents: bool,
+    /// It has bodies of its own.
+    bodies: bool,
+    /// It is a part with a part number in a list that folds.
+    folded: bool,
+    /// What it holds is listed under it if it is purchased ([`Request::purchased_contents`], all
+    /// levels).
+    open_purchased: bool,
+}
+
+/// How one placement counts.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+struct Step {
+    /// It is counted in a row here.
+    row: bool,
+    /// How what it holds is walked (`None`: not at all).
+    inside: Option<Walk>,
+    /// What it holds is listed as its row's children.
+    kit: bool,
+    /// What its row stands for when weighed.
+    holds: Holds,
+}
+
+/// How a placement counts in `view`: the one rule every list and every mass read. A reference
+/// counts nowhere and nothing inside it does; a phantom's own bodies, when it has any, are a row of
+/// their own (as a subassembly's are in parts only) and what it holds counts where it is placed; a purchased part is one row with nothing inside it listed (in all levels, its
+/// contents under it when asked); an inseparable part is one row, and in parts only its purchased
+/// parts are listed beside it; a normal part is a row in the structured views, in all levels with
+/// what it holds under it, and in parts only a subassembly is listed through its parts unless it
+/// has bodies of its own. A folded part is one row holding all it holds, what it holds listed under
+/// it (of an inseparable one, its purchased parts).
+fn classify(view: View, walk: Walk, bom_type: BomType, shape: Shape) -> Step {
+    let nothing = Step { row: false, inside: None, kit: false, holds: Holds::All };
+    let row = |holds| Step { row: true, holds, ..nothing };
+    let contents = |walk| shape.contents.then_some(walk);
+    match (bom_type, walk) {
+        (BomType::Reference, _) => nothing,
+        (BomType::Phantom, Walk::Listed) => Step { row: shape.bodies, inside: Some(Walk::Listed), kit: false, holds: Holds::Own },
+        (BomType::Phantom, Walk::PurchasedOnly) => Step { inside: Some(walk), ..nothing },
+        (BomType::Purchased, Walk::Listed) if view == View::AllLevels && shape.open_purchased => {
+            Step { inside: contents(Walk::Listed), kit: true, ..row(Holds::All) }
+        }
+        (BomType::Purchased, _) => row(Holds::All),
+        (_, Walk::PurchasedOnly) => Step { inside: contents(Walk::PurchasedOnly), ..nothing },
+        (BomType::Inseparable, Walk::Listed) if shape.folded => Step { inside: contents(Walk::PurchasedOnly), kit: true, ..row(Holds::All) },
+        (BomType::Inseparable, Walk::Listed) => match view {
+            View::PartsOnly => Step { inside: contents(Walk::PurchasedOnly), ..row(Holds::AllButPurchased) },
+            View::FirstLevel | View::AllLevels => row(Holds::All),
+        },
+        (BomType::Normal, Walk::Listed) if shape.folded => Step { inside: contents(Walk::Listed), kit: true, ..row(Holds::All) },
+        (BomType::Normal, Walk::Listed) => match view {
+            View::PartsOnly => Step { row: !shape.contents || shape.bodies, inside: contents(Walk::Listed), kit: false, holds: Holds::Own },
+            View::FirstLevel => row(Holds::All),
+            View::AllLevels => Step { inside: contents(Walk::Listed), kit: true, ..row(Holds::All) },
+        },
+    }
+}
+
+/// Whether a placement of `bom_type` inside a part adds to what the part's row stands for: a
+/// reference adds nothing, and what the list shows beside the row (what `classify` lists inside
+/// an inseparable part) isn't weighed with it.
+fn adds(holds: Holds, bom_type: BomType) -> bool {
+    match holds {
+        Holds::Own => false,
+        Holds::All => bom_type != BomType::Reference,
+        Holds::AllButPurchased => bom_type != BomType::Reference && !classify(View::PartsOnly, Walk::PurchasedOnly, bom_type, Shape::default()).row,
+    }
+}
+
+/// One placement a list counts in a row.
+struct Entry {
+    member: Member,
+    holds: Holds,
+    /// The folded placement (a position in the entries) whose children it is among.
+    kit: Option<usize>,
+}
+
+/// Every placement below `request.source` that `request` counts in a row, in one walk under one
+/// budget, and with `members` each one's occurrence path (else an empty path each).
+fn walk(tree: &Tree, request: &Request, members: bool) -> Result<(Vec<Entry>, Vec<Vec<u64>>)> {
+    struct Frame {
+        component: u64,
+        depth: usize,
+        /// Kept only with `members`.
+        path: Vec<u64>,
+        walk: Walk,
+        kit: Option<usize>,
+    }
+    let mut entries: Vec<Entry> = Vec::new();
+    let mut paths: Vec<Vec<u64>> = Vec::new();
+    let mut visited = 0usize;
+    let mut stack = vec![Frame { component: request.source, depth: 0, path: Vec::new(), walk: Walk::Listed, kit: None }];
+    while let Some(frame) = stack.pop() {
+        for placed in tree.contents(frame.component) {
+            visited += 1;
+            if frame.depth >= MAX_PLACEMENT_DEPTH || visited > MAX_PLACEMENTS {
+                return Err(too_big());
+            }
+            let component = placed.member.component;
+            // What a folded part holds is listed as parts only lists it, and isn't folded again; in
+            // all levels what any row holds is listed in all levels again.
+            let (view, folds) = match frame.kit {
+                Some(_) if request.view == View::AllLevels => (View::AllLevels, false),
+                Some(_) => (View::PartsOnly, false),
+                None => (request.view, request.fold),
+            };
+            let numbered = tree.components.get(&component).is_some_and(|c| c.metadata.part_number().is_some());
+            let shape = Shape {
+                contents: tree.children.contains_key(&component),
+                bodies: tree.bodies.contains_key(&component),
+                folded: folds && numbered,
+                open_purchased: request.purchased_contents,
+            };
+            let step = classify(view, frame.walk, placed.member.bom_type, shape);
+            let path = if members { [frame.path.as_slice(), &[placed.occurrence]].concat() } else { Vec::new() };
+            let here = entries.len();
+            if step.row {
+                entries.push(Entry { member: placed.member, holds: step.holds, kit: frame.kit });
+                paths.push(path.clone());
+            }
+            if let Some(walk) = step.inside {
+                let kit = if step.kit { Some(here) } else { frame.kit };
+                stack.push(Frame { component, depth: frame.depth + 1, path, walk, kit });
+            }
+        }
+    }
+    Ok((entries, paths))
+}
+
+impl Tree<'_> {
+    /// Component `id` (0: the design) as a title block shows it (#3875): what one of it weighs, as
+    /// a list weighs the assembly ([`Total::mass`]: its own bodies and all it holds but references),
+    /// and what that is made of, as its row would say. Each is worked out once for the tree.
+    pub fn component(&mut self, id: u64) -> Result<(Mass, Vec<String>)> {
+        if id != 0 && !self.components.contains_key(&id) {
+            return Err(DocError::Unknown(format!("component {id}")));
+        }
+        let mass = agree(&[self.weigh(id, Holds::All, 0)?]);
+        Ok((mass, self.made_of(id, Holds::All, 0)?))
+    }
+}
+
+/// The rows `request` lists, with the assembly's total; with `request.mass`, each row and the
+/// assembly weighed.
+pub fn list(tree: &mut Tree, request: &Request) -> Result<Bom> {
+    list_with(tree, request, false)
+}
+
+/// [`list`], with each row's members when asked (what item numbers and balloons will follow rows
+/// by, and what `row_of` reads), so a list made for its rows alone copies no paths.
+pub fn list_with(tree: &mut Tree, request: &Request, members: bool) -> Result<Bom> {
+    if request.source != 0 && !tree.components.contains_key(&request.source) {
+        return Err(DocError::Unknown(format!("component {}", request.source)));
+    }
+    let (entries, mut paths) = walk(tree, request, members)?;
+    // What each folded placement holds: the placements listed as its children.
+    let mut kids: Vec<Vec<usize>> = vec![Vec::new(); entries.len()];
+    for (i, entry) in entries.iter().enumerate() {
+        if let Some(of) = entry.kit.and_then(|k| kids.get_mut(k)) {
+            of.push(i);
+        }
+    }
+    let kits = tree.kits(&entries, &kids);
+    let listing = Listing { entries, kids, kits };
+    let top: Vec<usize> = listing.entries.iter().enumerate().filter(|(_, e)| e.kit.is_none()).map(|(i, _)| i).collect();
+    // What a folded part holds is gathered by part number in any list; all levels gathers every
+    // level as it gathers the first.
+    let under = if request.view == View::AllLevels { request.group } else { Group::PartNumber };
+    let mut rows = tree.level(&listing, &mut paths, &top, request.group, under, &[], 1);
+    let numbered = numbers::apply(&mut rows, numbers::saved(tree.doc, request.source, request.view));
+    let mut bom = Bom { source: request.source, rows, total: Total::default(), numbered, index: HashMap::new() };
+    if members {
+        bom.index_members();
+    }
+    tree.name_materials(&mut bom.rows)?;
+    if request.mass {
+        tree.weigh_rows(&mut bom.rows)?;
+        // After the rows, so what their definitions weigh is kept: only what no row holds (the
+        // assembly's own bodies) is measured again.
+        bom.total.mass = agree(&[tree.weigh(request.source, Holds::All, 0)?]);
+    }
+    let occurrences: u64 = bom.rows_deep().iter().map(|(_, row)| row.count).sum();
+    bom.total.occurrences = occurrences;
+    Ok(bom)
+}
+
+/// One of a row's parts, from what each of its definitions weighs: known when every one can be
+/// measured, has something to weigh, and they agree. Some with something to weigh and some with
+/// nothing differ.
+fn agree(weighed: &[Weighed]) -> Mass {
+    let Some(known) = weighed.iter().copied().collect::<Option<Vec<(f64, usize)>>>() else {
+        return Mass::Unknown(Unknown::Unmeasurable);
+    };
+    if known.iter().all(|&(_, bodies)| bodies == 0) {
+        return Mass::Unknown(Unknown::NothingToWeigh);
+    }
+    match known.first() {
+        Some(&(first, _)) if known.iter().any(|&(grams, bodies)| bodies == 0 || !same_mass(grams, first)) => Mass::Unknown(Unknown::Differs),
+        Some(&(first, _)) => Mass::Grams(first),
+        None => Mass::Unknown(Unknown::NothingToWeigh),
+    }
+}
+
+/// How closely the kernel's `measure` gives one solid's volume however it was modelled, relative to
+/// it (about 1e-4): a pin made as a cylinder and as a revolved rectangle measured 1.05e-5 apart
+/// (2026-10-26), and this is ten times that.
+pub const MEASURE_ACCURACY: f64 = 1e-4;
+
+/// Two masses of one part, measured from definitions modelled apart: one when they are within the
+/// kernel's measurement accuracy of each other.
+fn same_mass(a: f64, b: f64) -> bool {
+    (a - b).abs() <= MEASURE_ACCURACY * a.abs().max(b.abs())
+}
+
+/// `more` added to `total`; unknown when either is. The body count only says whether there is
+/// any, so a compact assembly with more placed bodies than a count holds saturates it.
+fn add(total: &mut Weighed, more: Weighed) {
+    *total = total.zip(more).map(|((grams, bodies), (g, n))| (grams + g, bodies.saturating_add(n)));
+}
+
+/// `name` added to `names` unless it is there already, so each is listed once, in first order.
+fn push_once(names: &mut Vec<String>, name: String) {
+    if !names.contains(&name) {
+        names.push(name);
+    }
+}
+
+fn too_big() -> DocError {
+    crate::assembly::too_many_placements()
+}
+
+#[cfg(test)]
+#[path = "bom_tests.rs"]
+#[allow(clippy::unwrap_used, clippy::expect_used)]
+mod tests;

crates/doc/src/bom/numbers.rs

@@ -0,0 +1,260 @@
+//! Item numbers (#3874). A view of an assembly is numbered once someone numbers it
+//! (`assembly.bom.renumber`, `assembly.bom.item.set`): from then on its rows' numbers are saved in
+//! the design ([`ItemNumbers`], `assembly.item_numbers`), each under its row's key, so a row keeps
+//! its number through part-number edits. Until then a view's numbers are its rows' positions,
+//! provisional, and listing it saves nothing.
+//!
+//! A row a numbered view has no number for (a part added since) shows the highest number saved at
+//! its level plus one, provisional, and [`record`] saves it: the engine runs it after each change,
+//! in the change's undo step. A row that goes keeps its number until a renumber, so a number on a
+//! printed drawing never comes to mean another part, and a part put back gets its number again.
+//! A renumber keeps locked numbers and skips them.
+
+use std::collections::{HashMap, HashSet};
+
+use serde::{Deserialize, Serialize};
+
+use super::{Group, Member, Request, Row, RowKey, Tree, View, item_text, list, list_order};
+use crate::{DocError, Document, MAX_PLACEMENTS, Result};
+
+/// The highest item number.
+pub const MAX_ITEM: u32 = 999_999;
+
+/// The item numbers saved for one view of one assembly, with the list options it was numbered
+/// with: the rows it numbers are listed by them.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct ItemNumbers {
+    /// The assembly: a component, or 0 for the design.
+    pub source: u64,
+    #[serde(rename = "levels")]
+    pub view: View,
+    #[serde(default, rename = "group_by")]
+    pub group: Group,
+    #[serde(default, rename = "group_children", skip_serializing_if = "std::ops::Not::not")]
+    pub fold: bool,
+    #[serde(default, rename = "show_purchased_contents", skip_serializing_if = "std::ops::Not::not")]
+    pub purchased_contents: bool,
+    /// One for each row numbered, rows gone since included, by key.
+    #[serde(default)]
+    pub items: Vec<ItemNumber>,
+}
+
+/// One row's saved item number.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct ItemNumber {
+    #[serde(flatten)]
+    pub(crate) key: RowKey,
+    pub number: u32,
+    #[serde(default, skip_serializing_if = "std::ops::Not::not")]
+    pub locked: bool,
+}
+
+impl ItemNumbers {
+    /// The list it numbers.
+    pub fn request(&self) -> Request {
+        Request { source: self.source, view: self.view, group: self.group, fold: self.fold, mass: false, purchased_contents: self.purchased_contents }
+    }
+}
+
+/// How [`number`] numbers a view.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum Numbering {
+    /// Each row without a saved number keeps the one it shows: the next at its level. Only a
+    /// numbered view has any to save.
+    NewRows,
+    /// Every row from `start` by `step`, level by level, in `order`. Locked rows keep their
+    /// numbers, which are skipped, and rows gone are forgotten.
+    Renumber { start: u32, step: u32, order: Order },
+    /// One row, by its item as the view shows it now (`[1, 2]` is 1.2): its number and its lock.
+    /// Every other row keeps the number it shows.
+    Set { row: Vec<u32>, item: Option<u32>, locked: Option<bool> },
+}
+
+/// The order a renumber goes in.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub enum Order {
+    /// The list's own, by part number (`list_order`).
+    #[default]
+    List,
+    /// The item numbers', closing the gaps.
+    Item,
+}
+
+/// The numbering saved for a view of an assembly, if it has been numbered.
+pub(super) fn saved(doc: &Document, source: u64, view: View) -> Option<&ItemNumbers> {
+    doc.assembly.item_numbers.iter().find(|n| n.source == source && n.view == view)
+}
+
+/// `rows`, as their view lists them, numbered as `saved` says: each its saved number, else the next
+/// at its level (provisional); then each level by item number, with duplicates marked. With no
+/// numbering they stay as listed, every number provisional. Whether the view is numbered.
+pub(super) fn apply(rows: &mut [Row], saved: Option<&ItemNumbers>) -> bool {
+    let Some(saved) = saved else { return false };
+    // A damaged file's number out of range is no number, and of a key saved twice the first holds.
+    let mut numbers: HashMap<&RowKey, &ItemNumber> = HashMap::new();
+    let mut highest: HashMap<Vec<Member>, u32> = HashMap::new();
+    for item in saved.items.iter().filter(|i| (1..=MAX_ITEM).contains(&i.number)) {
+        if numbers.contains_key(&item.key) {
+            continue;
+        }
+        numbers.insert(&item.key, item);
+        let h = highest.entry(item.key.parents.clone()).or_default();
+        *h = (*h).max(item.number);
+    }
+    number_level(rows, &numbers, &mut highest);
+    true
+}
+
+/// One level of [`apply`], and the levels under it. `highest` is the highest number at each level
+/// (by its parents), saved or shown.
+fn number_level(rows: &mut [Row], numbers: &HashMap<&RowKey, &ItemNumber>, highest: &mut HashMap<Vec<Member>, u32>) {
+    for row in rows.iter_mut() {
+        if let Some(saved) = numbers.get(&row.key) {
+            row.item = saved.number;
+            row.locked = saved.locked;
+            row.provisional = false;
+        } else {
+            let h = highest.entry(row.key.parents.clone()).or_default();
+            *h = h.saturating_add(1);
+            row.item = *h;
+        }
+        number_level(&mut row.children, numbers, highest);
+    }
+    rows.sort_by_key(|r| r.item);
+    let mut uses: HashMap<u32, usize> = HashMap::new();
+    for row in rows.iter() {
+        *uses.entry(row.item).or_default() += 1;
+    }
+    for row in rows.iter_mut() {
+        row.duplicate = uses.get(&row.item).is_some_and(|&n| n > 1);
+    }
+}
+
+/// The view `request` asks for, numbered as `how` says: the numbering to save, or `None` when that
+/// changes nothing.
+pub fn number(tree: &mut Tree, request: &Request, how: Numbering) -> Result<Option<ItemNumbers>> {
+    let request = Request { mass: false, ..*request };
+    // Borrowed from the design, not the tree: listing needs the tree, and nothing is copied until
+    // something changes.
+    let doc = tree.doc;
+    let old = saved(doc, request.source, request.view);
+    let mut bom = list(tree, &request)?;
+    let mut items: Vec<ItemNumber> = Vec::new();
+    match how {
+        Numbering::NewRows => {
+            let Some(old) = old else { return Ok(None) };
+            let room = MAX_PLACEMENTS.saturating_sub(old.items.len());
+            let shown = bom.rows_deep();
+            let new: Vec<ItemNumber> = shown
+                .iter()
+                .filter(|(_, r)| r.provisional && r.item <= MAX_ITEM)
+                .take(room)
+                .map(|(_, r)| ItemNumber { key: r.key.clone(), number: r.item, locked: false })
+                .collect();
+            if new.is_empty() {
+                return Ok(None);
+            }
+            items = [old.items.as_slice(), &new].concat();
+        }
+        Numbering::Set { row, item, locked } => {
+            if let Some(n) = item.filter(|n| !(1..=MAX_ITEM).contains(n)) {
+                return Err(DocError::Invalid(format!("an item number is 1 to {MAX_ITEM}, not {n}")));
+            }
+            let shown = bom.rows_deep();
+            let target = shown
+                .iter()
+                .find(|(i, _)| *i == row)
+                .map(|(_, r)| r.key.clone())
+                .ok_or_else(|| DocError::Unknown(format!("item {}", item_text(&row))))?;
+            // Rows not listed now keep what was saved for them; listed ones the number they show.
+            let listed: HashSet<&RowKey> = shown.iter().map(|(_, r)| &r.key).collect();
+            items.extend(old.iter().flat_map(|o| &o.items).filter(|i| !listed.contains(&i.key)).cloned());
+            items.extend(shown.iter().map(|(_, r)| ItemNumber { key: r.key.clone(), number: r.item, locked: r.locked }));
+            if let Some(it) = items.iter_mut().find(|i| i.key == target) {
+                it.number = item.unwrap_or(it.number);
+                it.locked = locked.unwrap_or(it.locked);
+            }
+        }
+        Numbering::Renumber { start, step, order } => {
+            for (name, n) in [("start", start), ("step", step)] {
+                if !(1..=MAX_ITEM).contains(&n) {
+                    return Err(DocError::Invalid(format!("`{name}` is 1 to {MAX_ITEM}, not {n}")));
+                }
+            }
+            renumber(&mut bom.rows, start, step, order, &mut items)?;
+        }
+    }
+    items.sort_by(|a, b| a.key.cmp(&b.key));
+    let new = ItemNumbers {
+        source: request.source,
+        view: request.view,
+        group: request.group,
+        fold: request.fold,
+        purchased_contents: request.purchased_contents,
+        items,
+    };
+    Ok((old != Some(&new)).then_some(new))
+}
+
+/// `rows` and the levels under them numbered from `start` by `step` in `order`, each level on its
+/// own, into `out`. Locked rows keep their numbers and the others skip them, so no two rows get one
+/// number.
+fn renumber(rows: &mut [Row], start: u32, step: u32, order: Order, out: &mut Vec<ItemNumber>) -> Result<()> {
+    if order == Order::List {
+        rows.sort_by(list_order);
+    }
+    let locked: HashSet<u32> = rows.iter().filter(|r| r.locked).map(|r| r.item).collect();
+    let mut next = start;
+    for row in rows.iter_mut() {
+        if !row.locked {
+            while locked.contains(&next) {
+                next = next.saturating_add(step);
+            }
+            if next > MAX_ITEM {
+                return Err(DocError::Invalid(format!("numbering from {start} by {step} passes {MAX_ITEM}")));
+            }
+            row.item = next;
+            next = next.saturating_add(step);
+        }
+        out.push(ItemNumber { key: row.key.clone(), number: row.item, locked: row.locked });
+        renumber(&mut row.children, start, step, order, out)?;
+    }
+    Ok(())
+}
+
+/// Each numbered view of the design with its new rows' numbers saved ([`Numbering::NewRows`]), and
+/// a component's views dropped once it is gone: the design's numberings to save, or `None` when
+/// none changed. A view that can't be listed now (too large) is left as it is. A view numbered
+/// twice (only a damaged file is) keeps its first numbering, the one listing reads.
+pub fn record(tree: &mut Tree) -> Option<Vec<ItemNumbers>> {
+    let doc = tree.doc;
+    // Each numbering that changes: its new self, or none when its component is gone or its view
+    // already has one, so no view is listed twice after a change.
+    let mut changes: Vec<(usize, Option<ItemNumbers>)> = Vec::new();
+    let mut views = HashSet::new();
+    for (i, numbering) in doc.assembly.item_numbers.iter().enumerate() {
+        let gone = numbering.source != 0 && !tree.components.contains_key(&numbering.source);
+        if gone || !views.insert((numbering.source, numbering.view)) {
+            changes.push((i, None));
+        } else if let Ok(Some(new)) = number(tree, &numbering.request(), Numbering::NewRows) {
+            changes.push((i, Some(new)));
+        }
+    }
+    if changes.is_empty() {
+        return None;
+    }
+    let mut out = doc.assembly.item_numbers.clone();
+    for (i, change) in changes.into_iter().rev() {
+        match change {
+            Some(new) => {
+                if let Some(numbering) = out.get_mut(i) {
+                    *numbering = new;
+                }
+            }
+            None => {
+                out.remove(i);
+            }
+        }
+    }
+    Some(out)
+}

crates/doc/src/bom/quantity.rs

@@ -0,0 +1,101 @@
+//! Quantities (#3874): what one placement of a component means in a bill of materials, typed in as
+//! its [`BOM_QUANTITY`](crate::metadata::BOM_QUANTITY) part property, and what a row's placements
+//! add up to. The property is an expression evaluated with the design's parameters, so a cable's
+//! length follows the design; without a unit it is a number of pieces (a pack of 4). Units come
+//! from expressions: mass, volume and area wait for their expression units (#4811).
+
+use std::cell::OnceCell;
+use std::collections::BTreeMap;
+
+use crate::expr::{self, Value};
+use crate::{DocError, Document, Result};
+
+/// The largest quantity of one placement, in pieces or millimetres.
+const MAX_AMOUNT: f64 = 1e9;
+
+/// The mass and volume units of #4811's expressions: until they reach expressions, a quantity
+/// naming one is refused for what it is, not as an unknown parameter.
+const MASS_AND_VOLUME: [&str; 7] = ["g", "kg", "lb", "ml", "mm³", "cm³", "m³"];
+
+/// What one placement of a component counts.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum Amount {
+    Pieces(f64),
+    /// Millimetres.
+    Length(f64),
+}
+
+/// A row's quantity: what its placements add up to.
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
+pub enum Quantity {
+    /// None of its definitions has a quantity: its count says it all.
+    #[default]
+    Count,
+    Pieces(f64),
+    /// Millimetres.
+    Length(f64),
+    Unknown(Uncounted),
+}
+
+/// Why a row's quantity isn't known.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Uncounted {
+    /// Pieces and lengths can't be added (a placement without a quantity is one piece).
+    Mixed,
+    /// A definition's quantity doesn't evaluate: a parameter it names is in error (or missing from
+    /// a damaged file).
+    Invalid,
+}
+
+/// Evaluate a quantity expression with `doc`'s parameters.
+pub fn amount(doc: &Document, text: &str) -> Result<Amount> {
+    amount_in(doc, &OnceCell::new(), text)
+}
+
+/// [`amount`] with the parameters' values shared between calls, evaluated only when an expression
+/// names one.
+pub(super) fn amount_in(doc: &Document, values: &OnceCell<BTreeMap<String, Value>>, text: &str) -> Result<Amount> {
+    let value = expr::eval_with(text, &|name| match values.get_or_init(|| doc.param_values().0).get(name) {
+        Some(v) => Ok(*v),
+        None if MASS_AND_VOLUME.contains(&name) => Err(mass_and_volume()),
+        None => Err(DocError::Expr(format!("unknown parameter `{name}`"))),
+    })?;
+    let amount = match (value.len, value.ang) {
+        (0, 0) => Amount::Pieces(value.v),
+        (1, 0) => Amount::Length(value.v),
+        (2, 0) => return Err(DocError::Invalid("not supported yet: area quantities".into())),
+        (3, 0) => return Err(mass_and_volume()),
+        _ => return Err(DocError::Invalid(format!("a quantity is a number of pieces or a length, not {}", value.describe()))),
+    };
+    let (Amount::Pieces(v) | Amount::Length(v)) = amount;
+    if !(v > 0.0 && v <= MAX_AMOUNT) {
+        return Err(DocError::Invalid(format!("a quantity is above 0 and at most {MAX_AMOUNT:e}")));
+    }
+    Ok(amount)
+}
+
+fn mass_and_volume() -> DocError {
+    DocError::Invalid("not supported yet: mass and volume quantities need the expression units of #4811".into())
+}
+
+/// What placements add up to, from each one's entry in the definitions' amounts: none without a
+/// quantity (one piece), `Some(None)` when its quantity doesn't evaluate.
+pub(super) fn add_up<'a>(amounts: impl IntoIterator<Item = Option<&'a Option<Amount>>>) -> Quantity {
+    let (mut pieces, mut length, mut typed) = (None, None, false);
+    for amount in amounts {
+        let (sum, n): (&mut Option<f64>, f64) = match amount {
+            None => (&mut pieces, 1.0),
+            Some(None) => return Quantity::Unknown(Uncounted::Invalid),
+            Some(Some(Amount::Pieces(n))) => (&mut pieces, *n),
+            Some(Some(Amount::Length(mm))) => (&mut length, *mm),
+        };
+        typed |= amount.is_some();
+        *sum.get_or_insert(0.0) += n;
+    }
+    match (pieces, length) {
+        _ if !typed => Quantity::Count,
+        (Some(_), Some(_)) => Quantity::Unknown(Uncounted::Mixed),
+        (None, Some(mm)) => Quantity::Length(mm),
+        (n, None) => Quantity::Pieces(n.unwrap_or_default()),
+    }
+}

crates/doc/src/bom_tests.rs

@@ -0,0 +1,922 @@
+use serde_json::json;
+
+use super::*;
+use crate::BomType::{Inseparable, Normal, Phantom, Purchased, Reference};
+use crate::{IDENTITY, Occurrence};
+
+/// A new component placed once in `parent`, and that placement.
+fn add(doc: &mut Document, name: &str, parent: u64) -> (u64, u64) {
+    let component = doc.add_component(Some(name), parent).unwrap();
+    (component, doc.occurrences.last().unwrap().id)
+}
+
+/// Another placement of `component` in `parent`.
+fn place(doc: &mut Document, component: u64, parent: u64) -> u64 {
+    doc.add_occurrence(component, parent, IDENTITY).unwrap()
+}
+
+/// A part property as a file holds it (reading never validates).
+fn set(doc: &mut Document, component: u64, key: &str, value: &str) {
+    doc.components.iter_mut().find(|c| c.id == component).unwrap().metadata.0.insert(key.into(), json!(value));
+}
+
+fn number(doc: &mut Document, component: u64, part_number: &str) {
+    set(doc, component, "part_number", part_number);
+}
+
+fn typed(doc: &mut Document, component: u64, bom_type: BomType) {
+    set(doc, component, "bom_type", bom_type.as_str());
+}
+
+/// What `request` lists for `doc` (none of whose components has bodies), with each row's members.
+fn listed(doc: &Document, request: Request) -> Result<Bom> {
+    let state = ModelState::default();
+    list_with(&mut Tree::new(doc, &state), &request, true)
+}
+
+fn view(view: View) -> Request {
+    Request { view, ..Request::default() }
+}
+
+fn folded(view: View) -> Request {
+    Request { view, fold: true, ..Request::default() }
+}
+
+/// Each row, followed by the rows under it: item, names, type, count and each.
+fn rows(bom: &Bom) -> Vec<(String, String, BomType, u64, u64)> {
+    bom.rows_deep().into_iter().map(|(item, r)| (item_text(&item), r.names.join("; "), r.bom_type, r.count, r.each)).collect()
+}
+
+fn row(item: &str, names: &str, bom_type: BomType, count: u64, each: u64) -> (String, String, BomType, u64, u64) {
+    (item.into(), names.into(), bom_type, count, each)
+}
+
+#[test]
+fn the_view_and_grouping_words_are_the_commands() {
+    for v in View::ALL {
+        assert_eq!(View::parse(v.as_str()), Some(v));
+    }
+    for g in Group::ALL {
+        assert_eq!(Group::parse(g.as_str()), Some(g));
+    }
+    assert_eq!((View::default().as_str(), Group::default().as_str()), ("flat", "part_number"), "what assembly.bom lists by default");
+    for word in ["", "deep", "Flat", "part number"] {
+        assert_eq!((View::parse(word), Group::parse(word)), (None, None), "{word}");
+    }
+}
+
+#[test]
+fn an_empty_assembly_lists_nothing_and_weighs_nothing() {
+    let mut doc = Document::default();
+    let empty = listed(&doc, Request { mass: true, ..Request::default() }).unwrap();
+    assert!(empty.rows.is_empty());
+    assert_eq!(empty.total, Total { occurrences: 0, mass: Mass::Unknown(Unknown::NothingToWeigh) });
+    assert_eq!(listed(&doc, Request::default()).unwrap().total.mass, Mass::NotAsked, "weighed only when asked");
+    // A component that holds nothing, as the assembly listed; one that isn't there is refused.
+    let (part, _) = add(&mut doc, "Part", 0);
+    for v in View::ALL {
+        assert!(listed(&doc, Request { source: part, view: v, ..Request::default() }).unwrap().rows.is_empty());
+    }
+    assert!(listed(&doc, Request { source: 999, ..Request::default() }).is_err());
+}
+
+#[test]
+fn one_part_is_one_row_named_by_its_lowest_member() {
+    let mut doc = Document::default();
+    let (part, occurrence) = add(&mut doc, "Part", 0);
+    for (v, stands_for) in [(View::PartsOnly, Holds::Own), (View::FirstLevel, Holds::All)] {
+        let bom = listed(&doc, view(v)).unwrap();
+        let [r] = bom.rows.as_slice() else { panic!("{bom:?}") };
+        assert_eq!(r.key, RowKey { parents: vec![], member: Member { component: part, bom_type: Normal } });
+        assert_eq!((r.item, r.count, r.each, r.stands_for, r.mass), (1, 1, 1, stands_for, Mass::NotAsked));
+        assert_eq!((&r.components, &r.names, &r.members), (&vec![part], &vec!["Part".to_string()], &vec![vec![occurrence]]));
+        assert!(r.children.is_empty() && r.materials.is_empty() && r.part_number.is_empty());
+        assert_eq!(bom.total.occurrences, 1);
+    }
+}
+
+#[test]
+fn a_row_is_named_by_its_lowest_member_not_by_its_part_number() {
+    let mut doc = Document::default();
+    let (a, oa) = add(&mut doc, "A", 0);
+    let (b, ob) = add(&mut doc, "B", 0);
+    number(&mut doc, a, "P");
+    number(&mut doc, b, "P");
+    let bom = listed(&doc, Request::default()).unwrap();
+    let [r] = bom.rows.as_slice() else { panic!("{bom:?}") };
+    assert_eq!((r.key.member.component, &r.components, &r.members, r.part_number.as_str()), (a, &vec![a, b], &vec![vec![oa], vec![ob]], "P"));
+    // Renumbering the lower one: its row goes with it, and the other's row is named by the other.
+    number(&mut doc, a, "Q");
+    let bom = listed(&doc, Request::default()).unwrap();
+    let keys: Vec<(&str, u64)> = bom.rows.iter().map(|r| (r.part_number.as_str(), r.key.member.component)).collect();
+    assert_eq!(keys, [("P", b), ("Q", a)]);
+}
+
+#[test]
+fn one_part_number_counted_as_two_types_is_two_rows() {
+    let mut doc = Document::default();
+    let (a, _) = add(&mut doc, "Made", 0);
+    let (b, _) = add(&mut doc, "Bought", 0);
+    number(&mut doc, a, "P");
+    number(&mut doc, b, "P");
+    typed(&mut doc, b, Purchased);
+    // A second placement of the made one, counted as bought: it joins the bought row.
+    let second = place(&mut doc, a, 0);
+    doc.occurrences.iter_mut().find(|o| o.id == second).unwrap().bom_type = Some(Purchased);
+    for v in View::ALL {
+        let bom = listed(&doc, view(v)).unwrap();
+        assert_eq!(rows(&bom), [row("1", "Made", Normal, 1, 1), row("2", "Made; Bought", Purchased, 2, 2)], "{v:?}");
+        let keys: Vec<Member> = bom.rows.iter().map(|r| r.key.member).collect();
+        assert_eq!(keys, [Member { component: a, bom_type: Normal }, Member { component: a, bom_type: Purchased }]);
+    }
+}
+
+#[test]
+fn a_phantom_in_a_phantom_promotes_what_it_holds_into_the_level_it_sits_in() {
+    let mut doc = Document::default();
+    let (kit, okit) = add(&mut doc, "Kit", 0);
+    let (set_, oset) = add(&mut doc, "Set", kit);
+    let oset2 = place(&mut doc, set_, kit);
+    let (screw, oscrew) = add(&mut doc, "Screw", set_);
+    let oscrew2 = place(&mut doc, screw, set_);
+    let alone = place(&mut doc, screw, 0);
+    typed(&mut doc, kit, Phantom);
+    typed(&mut doc, set_, Phantom);
+    let mut paths = vec![vec![okit, oset, oscrew], vec![okit, oset, oscrew2], vec![okit, oset2, oscrew], vec![okit, oset2, oscrew2], vec![alone]];
+    paths.sort();
+    for v in View::ALL {
+        let bom = listed(&doc, view(v)).unwrap();
+        assert_eq!(rows(&bom), [row("1", "Screw", Normal, 5, 5)], "{v:?}");
+        assert_eq!(bom.rows[0].members, paths);
+    }
+}
+
+#[test]
+fn a_reference_counts_nowhere_and_its_own_list_lists_what_it_holds() {
+    let mut doc = Document::default();
+    let (fixture, ofixture) = add(&mut doc, "Fixture", 0);
+    add(&mut doc, "Pin", fixture);
+    typed(&mut doc, fixture, Reference);
+    for v in View::ALL {
+        let bom = listed(&doc, Request { mass: true, ..view(v) }).unwrap();
+        assert_eq!((bom.rows.len(), bom.total.occurrences), (0, 0), "{v:?}");
+        assert_eq!(bom.total.mass, Mass::Unknown(Unknown::NothingToWeigh));
+        assert_eq!(rows(&listed(&doc, Request { source: fixture, view: v, ..Request::default() }).unwrap()), [row("1", "Pin", Normal, 1, 1)]);
+    }
+    // An occurrence counted as a reference, its component normal: the same.
+    set(&mut doc, fixture, "bom_type", "normal");
+    assert_eq!(rows(&listed(&doc, Request::default()).unwrap()), [row("1", "Pin", Normal, 1, 1)]);
+    doc.occurrences.iter_mut().find(|o| o.id == ofixture).unwrap().bom_type = Some(Reference);
+    assert!(listed(&doc, Request::default()).unwrap().rows.is_empty());
+}
+
+#[test]
+fn a_list_walks_64_levels_and_refuses_a_65th() {
+    let mut doc = Document::default();
+    let mut parent = 0;
+    for level in 1..=64 {
+        parent = add(&mut doc, &format!("L{level}"), parent).0;
+    }
+    let bom = listed(&doc, Request::default()).unwrap();
+    assert_eq!(rows(&bom), [row("1", "L64", Normal, 1, 1)]);
+    assert_eq!(bom.rows[0].members[0].len(), 64);
+    add(&mut doc, "L65", parent);
+    assert!(listed(&doc, Request::default()).is_err(), "refused, never listed in part");
+    // The first level only walks what the design places directly.
+    assert_eq!(rows(&listed(&doc, view(View::FirstLevel)).unwrap()), [row("1", "L1", Normal, 1, 1)]);
+}
+
+#[test]
+fn one_placement_budget_covers_the_whole_list_folded_parts_included() {
+    let mut doc = Document::default();
+    let (a, _) = add(&mut doc, "A", 0);
+    for _ in 1..1000 {
+        place(&mut doc, a, 0);
+    }
+    let (b, _) = add(&mut doc, "B", a);
+    for _ in 1..99 {
+        place(&mut doc, b, a);
+    }
+    // 1,000 As holding 99 Bs each: 100,000 placements, as many as one list walks.
+    let flat = listed(&doc, Request::default()).unwrap();
+    assert_eq!((rows(&flat), flat.total.occurrences), (vec![row("1", "B", Normal, 99_000, 99_000)], 99_000));
+    number(&mut doc, a, "A-1");
+    let kit = listed(&doc, folded(View::PartsOnly)).unwrap();
+    assert_eq!((rows(&kit), kit.total.occurrences), (vec![row("1", "A", Normal, 1000, 1000), row("1.1", "B", Normal, 99_000, 99)], 100_000));
+    let (a_row, b_row) = (&kit.rows[0], &kit.rows[0].children[0]);
+    assert_eq!(b_row.key, RowKey { parents: vec![a_row.key.member], member: Member { component: b, bom_type: Normal } });
+    assert_eq!(a_row.stands_for, Holds::All, "a folded part's row is the kit");
+    // One placement more, anywhere, is refused, folded or not: a folded part's contents are walked
+    // under the list's budget, not one of their own.
+    add(&mut doc, "C", 0);
+    for request in [Request::default(), folded(View::PartsOnly), folded(View::FirstLevel)] {
+        assert!(listed(&doc, request).is_err(), "{request:?}");
+    }
+    assert_eq!(listed(&doc, view(View::FirstLevel)).unwrap().total.occurrences, 1001, "the first level walks 1,001");
+}
+
+/// Kits used to be compared as text (`"#12×1"`): a part without a part number, whose id is 12,
+/// read the same as a part numbered "#12", and a part numbered "P×1\nQ" the same as a P and a Q.
+#[test]
+fn kits_are_told_apart_by_what_they_hold_not_by_how_it_reads() {
+    let mut doc = Document::default();
+    let bolt = |doc: &mut Document, name: &str| {
+        let (id, _) = add(doc, name, 0);
+        number(doc, id, "BOLT");
+        id
+    };
+    let (b1, b2, b3, b4) = (bolt(&mut doc, "Bolt 1"), bolt(&mut doc, "Bolt 2"), bolt(&mut doc, "Bolt 3"), bolt(&mut doc, "Bolt 4"));
+    let (plain, _) = add(&mut doc, "Plain", b1);
+    let (spelled, _) = add(&mut doc, "Spelled", b2);
+    number(&mut doc, spelled, &format!("#{plain}"));
+    let (pq, _) = add(&mut doc, "PQ", b3);
+    number(&mut doc, pq, "P×1\nQ");
+    let (p, _) = add(&mut doc, "P", b4);
+    let (q, _) = add(&mut doc, "Q", b4);
+    number(&mut doc, p, "P");
+    number(&mut doc, q, "Q");
+    let bolts = |doc: &Document| -> Vec<Vec<u64>> {
+        let bom = listed(doc, folded(View::PartsOnly)).unwrap();
+        bom.rows.iter().filter(|r| r.part_number == "BOLT").map(|r| r.components.clone()).collect()
+    };
+    let mut each: Vec<Vec<u64>> = bolts(&doc);
+    each.sort();
+    assert_eq!(each, [vec![b1], vec![b2], vec![b3], vec![b4]], "four kits, four rows");
+    // The same parts by part number are one kit, whichever definitions they are.
+    let b5 = bolt(&mut doc, "Bolt 5");
+    let (p2, _) = add(&mut doc, "P again", b5);
+    let (q2, _) = add(&mut doc, "Q again", b5);
+    number(&mut doc, p2, "P");
+    number(&mut doc, q2, "Q");
+    assert!(bolts(&doc).contains(&vec![b4, b5]));
+    let bom = listed(&doc, folded(View::PartsOnly)).unwrap();
+    let both = bom.rows.iter().find(|r| r.components == [b4, b5]).unwrap();
+    let inside: Vec<(&str, &[u64], u64, u64)> =
+        both.children.iter().map(|c| (c.part_number.as_str(), c.components.as_slice(), c.each, c.count)).collect();
+    assert_eq!(inside, [("P", &[p, p2][..], 1, 2), ("Q", &[q, q2][..], 1, 2)], "each bolt's, counted for both");
+    // The same parts counted as another type are another kit: a bolt whose Q is bought is a row of its own.
+    let b6 = bolt(&mut doc, "Bolt 6");
+    let (p3, _) = add(&mut doc, "P third", b6);
+    let (q3, bought) = add(&mut doc, "Q third", b6);
+    number(&mut doc, p3, "P");
+    number(&mut doc, q3, "Q");
+    doc.occurrences.iter_mut().find(|o| o.id == bought).unwrap().bom_type = Some(Purchased);
+    let each = bolts(&doc);
+    assert!(each.contains(&vec![b4, b5]) && each.contains(&vec![b6]), "{each:?}");
+}
+
+/// All levels walks under the list's one budget: 100,000 placements and 64 levels are listed, and
+/// one more of either is refused, never listed in part.
+#[test]
+fn all_levels_lists_at_each_cap_and_refuses_one_more() {
+    let mut doc = Document::default();
+    let (part, _) = add(&mut doc, "Part", 0);
+    let base = doc.occurrences.iter().map(|o| o.id).max().unwrap_or(0);
+    let placement =
+        |id: u64| Occurrence { id, component: part, parent: 0, name: format!("Part:{id}"), transform: IDENTITY, grounded: false, bom_type: None };
+    doc.occurrences.extend((1..MAX_PLACEMENTS as u64).map(|i| placement(base + i)));
+    let all = listed(&doc, view(View::AllLevels)).unwrap();
+    assert_eq!((all.rows.len(), all.total.occurrences), (1, MAX_PLACEMENTS as u64));
+    doc.occurrences.push(placement(base + MAX_PLACEMENTS as u64));
+    assert!(listed(&doc, view(View::AllLevels)).is_err(), "100,001 placements");
+    let mut doc = Document::default();
+    let mut parent = 0;
+    for i in 0..MAX_PLACEMENT_DEPTH {
+        parent = add(&mut doc, &format!("L{i}"), parent).0;
+    }
+    let all = listed(&doc, view(View::AllLevels)).unwrap();
+    assert_eq!(all.rows_deep().last().map(|(item, _)| item.len()), Some(MAX_PLACEMENT_DEPTH));
+    add(&mut doc, "Too deep", parent);
+    assert!(listed(&doc, view(View::AllLevels)).is_err(), "65 levels");
+}
+
+/// Two parts with one part number are one row only when what they hold is the same all the way
+/// down: here they differ two levels below, so in all levels they are two rows, each with its own.
+#[test]
+fn kits_are_compared_to_any_depth() {
+    let mut doc = Document::default();
+    let (a, _) = add(&mut doc, "A", 0);
+    let (b, _) = add(&mut doc, "B", 0);
+    let (x1, _) = add(&mut doc, "X1", a);
+    let (x2, _) = add(&mut doc, "X2", b);
+    let (bolt, _) = add(&mut doc, "Bolt", x1);
+    for (id, part_number) in [(a, "P"), (b, "P"), (x1, "X"), (x2, "X"), (bolt, "BOLT")] {
+        number(&mut doc, id, part_number);
+    }
+    let all = listed(&doc, view(View::AllLevels)).unwrap();
+    assert_eq!(
+        rows(&all),
+        [
+            row("1", "A", Normal, 1, 1),
+            row("1.1", "X1", Normal, 1, 1),
+            row("1.1.1", "Bolt", Normal, 1, 1),
+            row("2", "B", Normal, 1, 1),
+            row("2.1", "X2", Normal, 1, 1)
+        ],
+        "two P rows, never one with children at each 0"
+    );
+    // The same contents two levels down: one row again.
+    let (bolt2, _) = add(&mut doc, "Bolt 2", x2);
+    number(&mut doc, bolt2, "BOLT");
+    let all = listed(&doc, view(View::AllLevels)).unwrap();
+    assert_eq!(rows(&all), [row("1", "A; B", Normal, 2, 2), row("1.1", "X1; X2", Normal, 2, 1), row("1.1.1", "Bolt; Bolt 2", Normal, 2, 1)]);
+}
+
+/// What a folded part holds is listed as parts only lists it, in parts only and the first level,
+/// and isn't folded again: a numbered subassembly inside it is listed through its parts. In all
+/// levels it is listed in all levels again, so that subassembly is a row with its own rows.
+#[test]
+fn what_a_folded_part_holds_is_listed_as_parts_only_lists_it() {
+    let mut doc = Document::default();
+    let (machine, _) = add(&mut doc, "Machine", 0);
+    let (gearbox, _) = add(&mut doc, "Gearbox", machine);
+    let (shaft, _) = add(&mut doc, "Shaft", gearbox);
+    place(&mut doc, shaft, gearbox);
+    add(&mut doc, "Pin", gearbox);
+    for (id, part_number) in [(machine, "M-1"), (gearbox, "GB-1"), (shaft, "SH-1")] {
+        number(&mut doc, id, part_number);
+    }
+    for v in [View::PartsOnly, View::FirstLevel] {
+        let bom = listed(&doc, folded(v)).unwrap();
+        assert_eq!(rows(&bom), [row("1", "Machine", Normal, 1, 1), row("1.1", "Shaft", Normal, 2, 2), row("1.2", "Pin", Normal, 1, 1)], "{v:?}");
+    }
+    let all = listed(&doc, folded(View::AllLevels)).unwrap();
+    let nested = [
+        row("1", "Machine", Normal, 1, 1),
+        row("1.1", "Gearbox", Normal, 1, 1),
+        row("1.1.1", "Shaft", Normal, 2, 2),
+        row("1.1.2", "Pin", Normal, 1, 1),
+    ];
+    assert_eq!(rows(&all), nested);
+}
+
+/// Bolt (purchased) holding a nut; Frame (inseparable) holding a plate, a purchased clip and a
+/// weld kit (phantom) of a rivet and a purchased insert; Fixture (reference) holding a pin; Set
+/// (phantom) holding a screw; Sub (normal, numbered, no bodies) holding a washer. Each is placed
+/// once.
+fn mixed() -> (Document, BTreeMap<&'static str, u64>) {
+    let mut doc = Document::default();
+    let mut at = BTreeMap::new();
+    for (name, parent, bom_type) in [
+        ("Bolt", "", Purchased),
+        ("Nut", "Bolt", Normal),
+        ("Frame", "", Inseparable),
+        ("Plate", "Frame", Normal),
+        ("Clip", "Frame", Purchased),
+        ("Weld kit", "Frame", Phantom),
+        ("Rivet", "Weld kit", Normal),
+        ("Insert", "Weld kit", Purchased),
+        ("Fixture", "", Reference),
+        ("Pin", "Fixture", Normal),
+        ("Set", "", Phantom),
+        ("Screw", "Set", Normal),
+        ("Sub", "", Normal),
+        ("Washer", "Sub", Normal),
+    ] {
+        let parent = doc.find_component(parent).unwrap_or(0);
+        let (id, occurrence) = add(&mut doc, name, parent);
+        typed(&mut doc, id, bom_type);
+        at.insert(name, occurrence);
+    }
+    let sub = doc.find_component("Sub").unwrap();
+    number(&mut doc, sub, "SUB-1");
+    (doc, at)
+}
+
+#[test]
+fn row_of_finds_the_row_a_placement_is_counted_in() {
+    let (doc, at) = mixed();
+    let path = |names: &[&str]| -> Vec<u64> { names.iter().map(|n| at[*n]).collect() };
+    let state = ModelState::default();
+    let mut tree = Tree::new(&doc, &state);
+    let name = |r: std::result::Result<(Vec<u32>, &Row), Unlisted>| r.map(|(_, r)| r.names.join("; "));
+    let flat = list_with(&mut tree, &Request::default(), true).unwrap();
+    // Made for its rows alone, a list keeps no members.
+    assert!(list(&mut tree, &Request::default()).unwrap().rows.iter().all(|r| r.members.is_empty()));
+    let cases: &[(&[&str], std::result::Result<&str, Unlisted>)] = &[
+        (&["Bolt"], Ok("Bolt")),
+        (&["Bolt", "Nut"], Ok("Bolt")),
+        (&["Frame"], Ok("Frame")),
+        (&["Frame", "Plate"], Ok("Frame")),
+        (&["Frame", "Clip"], Ok("Clip")),
+        (&["Frame", "Weld kit"], Ok("Frame")),
+        (&["Frame", "Weld kit", "Rivet"], Ok("Frame")),
+        (&["Frame", "Weld kit", "Insert"], Ok("Insert")),
+        (&["Fixture"], Err(Unlisted::Reference)),
+        (&["Fixture", "Pin"], Err(Unlisted::Reference)),
+        (&["Set"], Err(Unlisted::NoRow)),
+        (&["Set", "Screw"], Ok("Screw")),
+        (&["Sub"], Err(Unlisted::NoRow)),
+        (&["Sub", "Washer"], Ok("Washer")),
+        (&[], Err(Unlisted::NoRow)),
+        (&["Nut"], Err(Unlisted::NotFound)),
+    ];
+    for (names, found) in cases {
+        assert_eq!(name(flat.row_of(&tree, &path(names))), found.map(String::from), "{names:?}");
+    }
+    assert_eq!(flat.row_of(&tree, &[999]).err(), Some(Unlisted::NotFound));
+    assert_eq!(flat.row_of(&tree, &vec![at["Bolt"]; 65]).err(), Some(Unlisted::NotFound));
+    let stands: Vec<(String, Holds)> = flat.rows.iter().map(|r| (r.names.join("; "), r.stands_for)).collect();
+    let want = [
+        ("Bolt", Holds::All),
+        ("Clip", Holds::All),
+        ("Frame", Holds::AllButPurchased),
+        ("Insert", Holds::All),
+        ("Screw", Holds::Own),
+        ("Washer", Holds::Own),
+    ];
+    assert_eq!(stands, want.map(|(n, h)| (n.to_string(), h)));
+
+    let top = list_with(&mut tree, &view(View::FirstLevel), true).unwrap();
+    let cases: &[(&[&str], &str)] = &[(&["Sub", "Washer"], "Sub"), (&["Set", "Screw"], "Screw"), (&["Frame", "Clip"], "Frame")];
+    for (names, found) in cases {
+        assert_eq!(name(top.row_of(&tree, &path(names))), Ok(found.to_string()), "{names:?}");
+    }
+    assert!(top.rows.iter().all(|r| r.stands_for == Holds::All));
+
+    let kit = list_with(&mut tree, &folded(View::PartsOnly), true).unwrap();
+    let (_, sub) = kit.row_of(&tree, &path(&["Sub"])).unwrap();
+    let (_, washer) = kit.row_of(&tree, &path(&["Sub", "Washer"])).unwrap();
+    assert_eq!((sub.names.join(""), sub.stands_for, washer.names.join("")), ("Sub".into(), Holds::All, "Washer".into()));
+    assert_eq!(washer.key.parents, [sub.key.member]);
+}
+
+/// Each placement is counted in one row or none, every view and grouping: the counts, the
+/// members and the total agree, and `row_of` finds each member's row.
+#[test]
+fn every_placement_is_in_one_row_or_none() {
+    let (mut doc, _) = mixed();
+    // More of the same: the subassembly and the bolt placed again, the washer twice in the subassembly.
+    for name in ["Sub", "Bolt"] {
+        let id = doc.find_component(name).unwrap();
+        place(&mut doc, id, 0);
+    }
+    let (washer, sub) = (doc.find_component("Washer").unwrap(), doc.find_component("Sub").unwrap());
+    place(&mut doc, washer, sub);
+    let state = ModelState::default();
+    let mut tree = Tree::new(&doc, &state);
+    for v in View::ALL {
+        for fold in [false, true] {
+            for group in Group::ALL {
+                let request = Request { view: v, fold, group, ..Request::default() };
+                let bom = list_with(&mut tree, &request, true).unwrap();
+                let deep = bom.rows_deep();
+                let mut seen: Vec<&Vec<u64>> = deep.iter().flat_map(|(_, r)| &r.members).collect();
+                assert_eq!(seen.len() as u64, bom.total.occurrences, "{request:?}");
+                assert!(deep.iter().all(|(_, r)| r.count == r.members.len() as u64), "{request:?}");
+                seen.sort();
+                seen.dedup();
+                assert_eq!(seen.len() as u64, bom.total.occurrences, "a placement in two rows: {request:?}");
+                for (_, r) in &deep {
+                    for m in &r.members {
+                        assert_eq!(bom.row_of(&tree, m).map(|(_, found)| &found.key), Ok(&r.key), "{request:?} {m:?}");
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[test]
+fn a_damaged_files_structure_is_listed_or_refused_never_followed_forever() {
+    let mut doc = Document::default();
+    let (a, _) = add(&mut doc, "A", 0);
+    let ghost =
+        |id, component, parent| Occurrence { id, component, parent, name: format!("{id}"), transform: IDENTITY, grounded: false, bom_type: None };
+    // An occurrence of a component that isn't there has no row and counts nowhere.
+    doc.occurrences.push(ghost(900, 999, 0));
+    assert_eq!(rows(&listed(&doc, Request::default()).unwrap()), [row("1", "A", Normal, 1, 1)]);
+    // A component placed inside itself: refused at the depth limit, never walked forever.
+    doc.occurrences.push(ghost(901, a, a));
+    assert!(listed(&doc, Request::default()).is_err());
+    // At the first level A is one row, but its material and its mass are what it holds: both walk inside.
+    assert!(listed(&doc, Request { mass: true, ..view(View::FirstLevel) }).is_err(), "weighing it walks inside");
+    assert!(listed(&doc, view(View::FirstLevel)).is_err(), "naming its material walks inside");
+}
+
+/// Moved from the engine's tests with the rule (it was `row_mass`), now with the reason.
+#[test]
+fn a_row_has_a_mass_only_when_its_definitions_are_weighed_and_agree() {
+    let (steel, aluminium, surface, empty): (Weighed, Weighed, Weighed, Weighed) =
+        (Some((392.5, 1)), Some((6.48, 1)), Some((0.0, 1)), Some((0.0, 0)));
+    assert_eq!(agree(&[steel, steel]), Mass::Grams(392.5));
+    assert_eq!(agree(&[steel, aluminium]), Mass::Unknown(Unknown::Differs));
+    assert_eq!(agree(&[surface, surface]), Mass::Grams(0.0), "a body that weighs nothing (a surface) is weighed");
+    assert_eq!(agree(&[surface, steel]), Mass::Unknown(Unknown::Differs));
+    assert_eq!(agree(&[empty]), Mass::Unknown(Unknown::NothingToWeigh), "nothing to weigh");
+    assert_eq!(agree(&[steel, empty]), Mass::Unknown(Unknown::Differs), "one weighs something, one nothing");
+    assert_eq!(agree(&[empty, steel]), Mass::Unknown(Unknown::Differs), "whichever comes first");
+    assert_eq!(agree(&[empty, empty]), Mass::Unknown(Unknown::NothingToWeigh));
+    assert_eq!(agree(&[None]), Mass::Unknown(Unknown::Unmeasurable), "not measured");
+    assert_eq!(agree(&[aluminium, None, steel]), Mass::Unknown(Unknown::Unmeasurable), "whichever definition it is");
+    assert_eq!(agree(&[]), Mass::Unknown(Unknown::NothingToWeigh));
+}
+
+/// What a row's part stands for leaves out a reference, and an inseparable part's purchased parts,
+/// which its list shows beside it; phantoms and inseparable parts inside are weighed through.
+#[test]
+fn what_adds_to_a_row_follows_what_it_stands_for() {
+    for t in BomType::ALL {
+        assert!(!adds(Holds::Own, t), "{t:?}");
+        assert_eq!(adds(Holds::All, t), t != Reference, "{t:?}");
+        assert_eq!(adds(Holds::AllButPurchased, t), !matches!(t, Reference | Purchased), "{t:?}");
+    }
+}
+
+/// `how` applied to the view `request` lists, its numbering saved as the engine saves it; whether
+/// anything changed.
+fn numbered(doc: &mut Document, request: Request, how: Numbering) -> bool {
+    let state = ModelState::default();
+    let Some(numbers) = super::number(&mut Tree::new(doc, &state), &request, how).unwrap() else { return false };
+    let saved = &mut doc.assembly.item_numbers;
+    saved.retain(|n| (n.source, n.view) != (numbers.source, numbers.view));
+    saved.push(numbers);
+    true
+}
+
+/// [`record`] as the engine runs it after a change; whether anything changed.
+fn recorded(doc: &mut Document) -> bool {
+    let state = ModelState::default();
+    let Some(numbers) = record(&mut Tree::new(doc, &state)) else { return false };
+    doc.assembly.item_numbers = numbers;
+    true
+}
+
+const RENUMBER: Numbering = Numbering::Renumber { start: 1, step: 1, order: Order::List };
+
+/// Each row, followed by the rows under it: item, names, and its numbering flags as letters
+/// (provisional, locked, duplicate).
+fn items(bom: &Bom) -> Vec<(String, String, String)> {
+    bom.rows_deep()
+        .into_iter()
+        .map(|(item, r)| {
+            let flags = [(r.provisional, 'p'), (r.locked, 'l'), (r.duplicate, 'd')].iter().filter(|(on, _)| *on).map(|(_, c)| *c).collect();
+            (item_text(&item), r.names.join("; "), flags)
+        })
+        .collect()
+}
+
+fn item(item: &str, names: &str, flags: &str) -> (String, String, String) {
+    (item.into(), names.into(), flags.into())
+}
+
+/// Parts A, B and C at the top, part numbers P1 to P3.
+fn three_parts() -> (Document, [(u64, u64); 3]) {
+    let mut doc = Document::default();
+    let parts = ["A", "B", "C"].map(|name| add(&mut doc, name, 0));
+    for (i, (part, _)) in parts.iter().enumerate() {
+        number(&mut doc, *part, &format!("P{}", i + 1));
+    }
+    (doc, parts)
+}
+
+#[test]
+fn numbering_a_view_saves_its_numbers_and_new_rows_take_the_next() {
+    let (mut doc, [_, (b, ob), _]) = three_parts();
+    // Never numbered: positions, provisional, and nothing saved by a change.
+    let bom = listed(&doc, Request::default()).unwrap();
+    assert!(!bom.numbered);
+    assert_eq!(items(&bom), [item("1", "A", "p"), item("2", "B", "p"), item("3", "C", "p")]);
+    assert!(!recorded(&mut doc), "a design never numbered saves nothing");
+    assert!(numbered(&mut doc, Request::default(), RENUMBER));
+    assert!(!numbered(&mut doc, Request::default(), RENUMBER), "the same numbers again change nothing");
+    let bom = listed(&doc, Request::default()).unwrap();
+    assert!(bom.numbered);
+    assert_eq!(items(&bom), [item("1", "A", ""), item("2", "B", ""), item("3", "C", "")]);
+    // A new part, first by part number: the highest number + 1, listed by it, saved by the next change.
+    let (d, _) = add(&mut doc, "D", 0);
+    number(&mut doc, d, "P0");
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()).last(), Some(&item("4", "D", "p")));
+    assert!(recorded(&mut doc));
+    assert!(!recorded(&mut doc), "saved once");
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()).last(), Some(&item("4", "D", "")));
+    // B removed leaves a gap, and back it has its number again.
+    doc.occurrences.retain(|o| o.id != ob);
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()), [item("1", "A", ""), item("3", "C", ""), item("4", "D", "")]);
+    assert!(!recorded(&mut doc), "a gap isn't filled");
+    // Setting another row's number keeps B's: it isn't listed, but it is saved.
+    assert!(numbered(&mut doc, Request::default(), Numbering::Set { row: vec![1], item: None, locked: Some(true) }));
+    assert!(numbered(&mut doc, Request::default(), Numbering::Set { row: vec![1], item: None, locked: Some(false) }));
+    let (e, _) = add(&mut doc, "E", 0);
+    assert!(recorded(&mut doc));
+    place(&mut doc, b, 0);
+    let bom = listed(&doc, Request::default()).unwrap();
+    assert_eq!(items(&bom), [item("1", "A", ""), item("2", "B", ""), item("3", "C", ""), item("4", "D", ""), item("5", "E", "")]);
+    assert_eq!(bom.rows.last().map(|r| r.key.member.component), Some(e));
+    // A renumber closing the gaps in item order, or in the list's order (by part number).
+    doc.occurrences.retain(|o| o.component != b);
+    assert!(numbered(&mut doc, Request::default(), Numbering::Renumber { start: 1, step: 1, order: Order::Item }));
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()), [item("1", "A", ""), item("2", "C", ""), item("3", "D", ""), item("4", "E", "")]);
+    assert!(numbered(&mut doc, Request::default(), Numbering::Renumber { start: 10, step: 5, order: Order::List }));
+    assert_eq!(
+        items(&listed(&doc, Request::default()).unwrap()),
+        [item("10", "D", ""), item("15", "A", ""), item("20", "C", ""), item("25", "E", "")]
+    );
+    // The renumber forgot B: back, it is new.
+    place(&mut doc, b, 0);
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()).last(), Some(&item("26", "B", "p")));
+}
+
+/// A view numbered twice, which only a damaged file has: listing reads the first numbering, and
+/// recording drops the second, so a change never lists the view again for it.
+#[test]
+fn a_view_numbered_twice_keeps_its_first_numbering() {
+    let (mut doc, _) = three_parts();
+    assert!(numbered(&mut doc, Request::default(), RENUMBER));
+    let mut second = doc.assembly.item_numbers[0].clone();
+    second.items.iter_mut().for_each(|i| i.number += 10);
+    doc.assembly.item_numbers.push(second);
+    let first = [item("1", "A", ""), item("2", "B", ""), item("3", "C", "")];
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()), first);
+    assert!(recorded(&mut doc));
+    assert_eq!(doc.assembly.item_numbers.len(), 1);
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()), first);
+    assert!(!recorded(&mut doc));
+}
+
+#[test]
+fn a_row_keeps_its_number_through_a_part_number_edit() {
+    let (mut doc, [(a, _), _, _]) = three_parts();
+    assert!(numbered(&mut doc, Request::default(), RENUMBER));
+    number(&mut doc, a, "P9");
+    assert!(!recorded(&mut doc), "no new row");
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()), [item("1", "A", ""), item("2", "B", ""), item("3", "C", "")]);
+}
+
+/// The defect the plan names: a renumber with locked rows never gives two rows one number.
+#[test]
+fn a_renumber_keeps_locked_numbers_and_never_gives_two_rows_one() {
+    let (mut doc, _) = three_parts();
+    let (d, _) = add(&mut doc, "D", 0);
+    number(&mut doc, d, "P4");
+    // Setting a number numbers the view first; one another row has is marked on both.
+    assert!(numbered(&mut doc, Request::default(), Numbering::Set { row: vec![3], item: Some(2), locked: Some(true) }));
+    assert_eq!(
+        items(&listed(&doc, Request::default()).unwrap()),
+        [item("1", "A", ""), item("2", "B", "d"), item("2", "C", "ld"), item("4", "D", "")]
+    );
+    for (start, step, want) in [(1, 1, ["1", "3", "2", "4"]), (2, 1, ["3", "4", "2", "5"]), (1, 2, ["1", "3", "2", "5"])] {
+        assert!(numbered(&mut doc, Request::default(), Numbering::Renumber { start, step, order: Order::List }));
+        let bom = listed(&doc, Request::default()).unwrap();
+        let by_name: BTreeMap<String, (String, String)> = items(&bom).into_iter().map(|(i, n, f)| (n, (i, f))).collect();
+        let got: Vec<&str> = ["A", "B", "C", "D"].iter().map(|n| by_name[*n].0.as_str()).collect();
+        assert_eq!(got, want, "from {start} by {step}");
+        assert!(bom.rows.iter().all(|r| !r.duplicate), "from {start} by {step}");
+        assert_eq!(by_name["C"].1, "l");
+    }
+    // Unlocked, the next renumber moves it.
+    assert!(numbered(&mut doc, Request::default(), Numbering::Set { row: vec![2], item: None, locked: Some(false) }));
+    assert!(numbered(&mut doc, Request::default(), RENUMBER));
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()), [item("1", "A", ""), item("2", "B", ""), item("3", "C", ""), item("4", "D", "")]);
+}
+
+#[test]
+fn all_levels_are_numbered_within_each_parent() {
+    let mut doc = Document::default();
+    let (frame, _) = add(&mut doc, "Frame", 0);
+    let (bolt, _) = add(&mut doc, "Bolt", 0);
+    number(&mut doc, frame, "F");
+    number(&mut doc, bolt, "B");
+    let (beam, _) = add(&mut doc, "Beam", frame);
+    number(&mut doc, beam, "F1");
+    let all = view(View::AllLevels);
+    assert!(numbered(&mut doc, all, RENUMBER));
+    assert_eq!(items(&listed(&doc, all).unwrap()), [item("1", "Bolt", ""), item("2", "Frame", ""), item("2.1", "Beam", "")]);
+    // A plate in the frame is the frame's next; the design's parts-only view isn't numbered.
+    let (plate, _) = add(&mut doc, "Plate", frame);
+    number(&mut doc, plate, "F0");
+    assert_eq!(items(&listed(&doc, all).unwrap()).last(), Some(&item("2.2", "Plate", "p")));
+    assert!(recorded(&mut doc));
+    assert_eq!(items(&listed(&doc, all).unwrap()).last(), Some(&item("2.2", "Plate", "")));
+    assert!(!listed(&doc, Request::default()).unwrap().numbered);
+    // Renumbered in the list's order, each level from the start.
+    assert!(numbered(&mut doc, all, Numbering::Renumber { start: 5, step: 5, order: Order::List }));
+    assert_eq!(
+        items(&listed(&doc, all).unwrap()),
+        [item("5", "Bolt", ""), item("10", "Frame", ""), item("10.5", "Plate", ""), item("10.10", "Beam", "")]
+    );
+    // A component's own list is numbered apart from the design's.
+    let own = Request { source: frame, ..all };
+    assert!(!listed(&doc, own).unwrap().numbered);
+    assert!(numbered(&mut doc, own, RENUMBER));
+    assert_eq!(items(&listed(&doc, own).unwrap()), [item("1", "Plate", ""), item("2", "Beam", "")]);
+    assert_eq!(items(&listed(&doc, all).unwrap())[2], item("10.5", "Plate", ""));
+}
+
+/// A numbering keeps the list options it was made with: the next change saves the rows they list.
+/// A list with other options reads the same numbers by row, the rest provisional.
+#[test]
+fn a_numbering_keeps_its_list_options_and_other_lists_read_its_numbers() {
+    let (mut doc, [_, (b, _), _]) = three_parts();
+    number(&mut doc, b, "P1");
+    let by_definition = Request { group: Group::Definition, ..Request::default() };
+    assert!(numbered(&mut doc, Request::default(), RENUMBER));
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()), [item("1", "A; B", ""), item("2", "C", "")]);
+    assert_eq!(items(&listed(&doc, by_definition).unwrap()), [item("1", "A", ""), item("2", "C", ""), item("3", "B", "p")]);
+    assert!(!recorded(&mut doc), "the numbering lists by part number: nothing new");
+    assert!(numbered(&mut doc, by_definition, Numbering::Set { row: vec![3], item: Some(7), locked: None }));
+    let saved = &doc.assembly.item_numbers;
+    assert_eq!((saved.len(), saved[0].group), (1, Group::Definition), "one numbering a view, with the options last used");
+    assert_eq!(items(&listed(&doc, by_definition).unwrap()), [item("1", "A", ""), item("2", "C", ""), item("7", "B", "")]);
+}
+
+#[test]
+fn numbers_are_refused_outside_their_range_and_rows_are_found_as_shown() {
+    let (mut doc, _) = three_parts();
+    let refused = |doc: &mut Document, how: Numbering| {
+        let state = ModelState::default();
+        super::number(&mut Tree::new(doc, &state), &Request::default(), how).unwrap_err().to_string()
+    };
+    for (start, step) in [(0, 1), (1, 0), (MAX_ITEM + 1, 1)] {
+        assert!(refused(&mut doc, Numbering::Renumber { start, step, order: Order::List }).contains("1 to 999999"), "{start} by {step}");
+    }
+    assert!(refused(&mut doc, Numbering::Renumber { start: MAX_ITEM - 1, step: 1, order: Order::List }).contains("passes 999999"));
+    assert!(refused(&mut doc, Numbering::Renumber { start: 1, step: MAX_ITEM, order: Order::List }).contains("passes 999999"));
+    assert!(refused(&mut doc, Numbering::Set { row: vec![4], item: Some(1), locked: None }).contains("item 4"));
+    assert!(refused(&mut doc, Numbering::Set { row: vec![1, 1], item: Some(1), locked: None }).contains("item 1.1"));
+    assert!(refused(&mut doc, Numbering::Set { row: vec![1], item: Some(0), locked: None }).contains("1 to 999999"));
+    assert!(doc.assembly.item_numbers.is_empty(), "nothing saved");
+    // The highest number is taken; a renumber that would pass it is refused whole.
+    assert!(numbered(&mut doc, Request::default(), Numbering::Renumber { start: MAX_ITEM - 2, step: 1, order: Order::List }));
+    assert_eq!(listed(&doc, Request::default()).unwrap().rows.last().map(|r| r.item), Some(MAX_ITEM));
+}
+
+/// A damaged file's numbers: one out of range is no number, and of a key saved twice the first
+/// holds. A component's numbering goes with it.
+#[test]
+fn saved_numbers_are_read_leniently_and_go_with_their_component() {
+    let (mut doc, [(a, _), (b, _), (c, _)]) = three_parts();
+    let key = |component| RowKey { parents: vec![], member: Member { component, bom_type: Normal } };
+    let saved = |key, number| ItemNumber { key, number, locked: false };
+    doc.assembly.item_numbers.push(ItemNumbers {
+        source: 0,
+        view: View::PartsOnly,
+        group: Group::PartNumber,
+        fold: false,
+        purchased_contents: false,
+        items: vec![saved(key(a), 4), saved(key(a), 9), saved(key(b), 0), saved(key(c), MAX_ITEM + 1)],
+    });
+    assert_eq!(items(&listed(&doc, Request::default()).unwrap()), [item("4", "A", ""), item("5", "B", "p"), item("6", "C", "p")]);
+    let (sub, _) = add(&mut doc, "Sub", 0);
+    add(&mut doc, "Inner", sub);
+    assert!(numbered(&mut doc, Request { source: sub, ..Request::default() }, RENUMBER));
+    assert_eq!(doc.assembly.item_numbers.len(), 2);
+    doc.components.retain(|c| c.id != sub);
+    doc.occurrences.retain(|o| o.component != sub && o.parent != sub);
+    assert!(recorded(&mut doc));
+    assert_eq!(doc.assembly.item_numbers.iter().map(|n| n.source).collect::<Vec<_>>(), [0], "the design's is kept");
+}
+
+/// Numbers are saved in the design under `assembly.item_numbers`, and change no geometry.
+#[test]
+fn item_numbers_are_saved_and_are_part_properties() {
+    let (mut doc, _) = three_parts();
+    let before = doc.clone();
+    assert!(numbered(&mut doc, Request { fold: true, ..view(View::AllLevels) }, RENUMBER));
+    assert!(doc.differs_only_in_part_properties(&before));
+    assert!(!doc.differs_only_in_part_properties(&doc.clone()), "no change is no part-properties change");
+    let json = serde_json::to_value(&doc.assembly).unwrap();
+    let first = &json["item_numbers"][0];
+    assert_eq!(
+        (&first["source"], &first["levels"], &first["group_by"], &first["group_children"]),
+        (&json!(0), &json!("all"), &json!("part_number"), &json!(true))
+    );
+    assert_eq!(first["items"][0], json!({"member": {"component": doc.components[0].id, "bom_type": "normal"}, "number": 1}));
+    // Through the whole design, as a save writes it: a design whose assembly holds only numbers keeps them.
+    assert_eq!(Document::from_json(&doc.to_json()).unwrap().assembly, doc.assembly);
+    assert!(serde_json::to_value(&before.assembly).unwrap().get("item_numbers").is_none(), "a design never numbered saves nothing new");
+}
+
+#[test]
+fn a_quantity_is_pieces_or_a_length_with_the_designs_parameters() {
+    let mut doc = Document::default();
+    doc.set_param("span", "100", Some("mm"), None).unwrap();
+    doc.set_param("packs", "3", Some(""), None).unwrap();
+    let amount = |text: &str| super::amount(&doc, text);
+    assert_eq!(amount("4").unwrap(), Amount::Pieces(4.0));
+    assert_eq!(amount("packs * 4").unwrap(), Amount::Pieces(12.0));
+    assert_eq!(amount("2.5 m").unwrap(), Amount::Length(2500.0));
+    assert_eq!(amount("10 in").unwrap(), Amount::Length(254.0));
+    assert_eq!(amount("2 * span + 50").unwrap(), Amount::Length(250.0), "a bare number beside a length is mm");
+    let refused = |text: &str| amount(text).unwrap_err().to_string();
+    assert!(refused("90 deg").contains("a number of pieces or a length"), "{}", refused("90 deg"));
+    assert!(refused("span * span").contains("not supported yet: area"));
+    for mass_or_volume in ["span^3", "50 g", "0.5 kg", "2 lb", "500 ml"] {
+        assert!(refused(mass_or_volume).contains("not supported yet: mass and volume"), "{mass_or_volume}: {}", refused(mass_or_volume));
+    }
+    for out_of_range in ["0", "-1", "-2 m", "1e9 + 1", "1001 km"] {
+        assert!(refused(out_of_range).contains("above 0"), "{out_of_range}: {}", refused(out_of_range));
+    }
+    assert_eq!(amount("1e9").unwrap(), Amount::Pieces(1e9), "the cap itself");
+    assert!(refused("cable_length").contains("unknown parameter `cable_length`"));
+    assert!(amount("").is_err() && amount("2 *").is_err());
+}
+
+#[test]
+fn a_rows_quantity_adds_up_its_placements() {
+    let mut doc = Document::default();
+    doc.set_param("cable_length", "2.5", Some("m"), None).unwrap();
+    let (cable, _) = add(&mut doc, "Cable", 0);
+    set(&mut doc, cable, "bom_quantity", "cable_length");
+    place(&mut doc, cable, 0);
+    place(&mut doc, cable, 0);
+    let (pack, _) = add(&mut doc, "Pack", 0);
+    set(&mut doc, pack, "bom_quantity", "4");
+    place(&mut doc, pack, 0);
+    add(&mut doc, "Plate", 0);
+    // Two definitions of one part number: one with a length, one a piece.
+    let (hose, _) = add(&mut doc, "Hose", 0);
+    let (hose_b, _) = add(&mut doc, "Hose B", 0);
+    number(&mut doc, hose, "H-1");
+    number(&mut doc, hose_b, "H-1");
+    set(&mut doc, hose, "bom_quantity", "500 mm");
+    // A subassembly placed twice holding the pack once.
+    let (kit, _) = add(&mut doc, "Kit", 0);
+    place(&mut doc, kit, 0);
+    place(&mut doc, pack, kit);
+    let quantities = |doc: &Document, request: Request| -> Vec<(String, Quantity)> {
+        listed(doc, request).unwrap().rows_deep().into_iter().map(|(_, r)| (r.names.join("; "), r.quantity)).collect()
+    };
+    let q = quantities(&doc, view(View::PartsOnly));
+    let of = |q: &[(String, Quantity)], name: &str| q.iter().find(|(n, _)| n == name).map(|(_, q)| *q);
+    assert_eq!(of(&q, "Cable"), Some(Quantity::Length(7500.0)), "{q:?}");
+    assert_eq!(of(&q, "Pack"), Some(Quantity::Pieces(16.0)), "two of its own and one in each kit: {q:?}");
+    assert_eq!(of(&q, "Plate"), Some(Quantity::Count));
+    assert_eq!(of(&q, "Hose; Hose B"), Some(Quantity::Unknown(Uncounted::Mixed)));
+    // The kit's row in the top level; its own pack listed under it in all levels.
+    let q = quantities(&doc, view(View::AllLevels));
+    assert_eq!(q.iter().filter(|(n, _)| n == "Pack").map(|(_, q)| *q).collect::<Vec<_>>(), [Quantity::Pieces(8.0), Quantity::Pieces(8.0)], "{q:?}");
+    // A placement without a quantity beside packs counts one piece: a box of 4 and a loose one.
+    let (boxed, _) = add(&mut doc, "Box", 0);
+    let (loose, _) = add(&mut doc, "Loose", 0);
+    number(&mut doc, boxed, "K-1");
+    number(&mut doc, loose, "K-1");
+    set(&mut doc, boxed, "bom_quantity", "4");
+    assert_eq!(of(&quantities(&doc, view(View::PartsOnly)), "Box; Loose"), Some(Quantity::Pieces(5.0)));
+    // A parameter deleted (a damaged file): that row is unknown, the list still works.
+    doc.params.retain(|p| p.name != "cable_length");
+    let q = quantities(&doc, view(View::PartsOnly));
+    assert_eq!(of(&q, "Cable"), Some(Quantity::Unknown(Uncounted::Invalid)));
+    assert_eq!(of(&q, "Pack"), Some(Quantity::Pieces(16.0)));
+}
+
+#[test]
+fn a_virtual_component_holding_something_is_named() {
+    let mut doc = Document::default();
+    let (grease, _) = add(&mut doc, "Grease", 0);
+    let (frame, _) = add(&mut doc, "Frame", 0);
+    let (bolt, _) = add(&mut doc, "Bolt", frame);
+    assert!(doc.virtual_holding().is_empty());
+    set_virtual(&mut doc, grease);
+    assert!(doc.virtual_holding().is_empty(), "an empty virtual component holds nothing");
+    place(&mut doc, bolt, grease);
+    assert_eq!(doc.virtual_holding(), [grease]);
+    set_virtual(&mut doc, frame);
+    assert_eq!(doc.virtual_holding(), [grease, frame]);
+}
+
+fn set_virtual(doc: &mut Document, component: u64) {
+    doc.components.iter_mut().find(|c| c.id == component).unwrap().metadata.0.insert("virtual".into(), json!(true));
+}
+
+#[test]
+fn a_quantity_uses_its_parameters_as_any_expression_does() {
+    let mut doc = Document::default();
+    doc.set_param("span", "100", Some("mm"), None).unwrap();
+    let (cable, _) = add(&mut doc, "Cable", 0);
+    set(&mut doc, cable, "bom_quantity", "2 * span");
+    assert_eq!(doc.param_users("span"), [crate::ParamUser::Quantity { component: cable, name: "Cable".into() }]);
+    assert!(doc.remove_param("span").unwrap_err().to_string().contains("component Cable (quantity)"));
+    assert_eq!(doc.rename_param("span", "width").unwrap(), 1);
+    assert_eq!(doc.components[0].metadata.bom_quantity(), Some("2 * width"));
+    assert_eq!(amount(&doc, "2 * width").unwrap(), Amount::Length(200.0));
+}
+
+/// A balloon's item reads the row its part is counted in, by a path from the top of the design: in
+/// all levels with the rows it is under, in a component's list only below that component, and the
+/// reasons there is none stay apart.
+#[test]
+fn item_of_reads_a_balloons_row() {
+    let (doc, at) = mixed();
+    let path = |names: &[&str]| -> Vec<u64> { names.iter().map(|n| at[*n]).collect() };
+    let state = ModelState::default();
+    let mut tree = Tree::new(&doc, &state);
+    let all = list_with(&mut tree, &Request { view: View::AllLevels, ..Request::default() }, true).unwrap();
+    let (washer, _) = all.row_of(&tree, &path(&["Sub", "Washer"])).unwrap();
+    assert_eq!(washer.len(), 2, "under its subassembly");
+    assert_eq!(all.item_of(&tree, &path(&["Sub", "Washer"])), Ok(item_text(&washer)));
+    assert!(all.item_of(&tree, &path(&["Sub", "Washer"])).unwrap().contains('.'));
+
+    let sub = doc.find_component("Sub").unwrap();
+    let of_sub = list_with(&mut tree, &Request { source: sub, ..Request::default() }, true).unwrap();
+    assert_eq!(of_sub.item_of(&tree, &path(&["Sub", "Washer"])), Ok("1".to_string()), "cut to start below Sub");
+    assert_eq!(of_sub.item_of(&tree, &path(&["Sub"])), Err(Unlisted::NoRow), "the assembly listed has no row");
+    assert_eq!(of_sub.item_of(&tree, &path(&["Bolt"])), Err(Unlisted::NotFound), "not through Sub");
+    assert_eq!(of_sub.item_of(&tree, &[]), Err(Unlisted::NotFound));
+
+    assert_eq!(all.item_of(&tree, &path(&["Fixture", "Pin"])), Err(Unlisted::Reference));
+    assert_eq!(all.item_of(&tree, &[999]), Err(Unlisted::NotFound));
+    assert_eq!(all.item_of(&tree, &vec![at["Bolt"]; 65]), Err(Unlisted::NotFound));
+    assert!(of_sub.item_of(&tree, &vec![at["Sub"]; 65]).is_err());
+    assert_eq!(all.item_of(&tree, &[]), Err(Unlisted::NoRow));
+}

crates/doc/src/config_styles.rs

@@ -12,6 +12,9 @@ pub(crate) fn shell_plane_family(planes: impl IntoIterator<Item = Option<solidco
     first.origin.is_finite() && first.x.is_finite() && first.y.is_finite() && planes.all(|plane| plane == Some(first))
 }
 
+/// The longest face or edge name a saved model reference keeps, in bytes.
+pub const MAX_REFERENCE_NAME_BYTES: usize = 512;
+
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 #[serde(deny_unknown_fields)]
 pub struct ConfigFaceTarget {
@@ -38,7 +41,7 @@ impl ConfigFaceTarget {
         if self.body.is_empty()
             || self.body.len() > 128
             || self.name.is_empty()
-            || self.name.len() > 512
+            || self.name.len() > MAX_REFERENCE_NAME_BYTES
             || self.origin_feature == 0
             || [self.point.x, self.point.y, self.point.z].iter().any(|v| !v.is_finite() || v.abs() > 1e9)
         {
@@ -53,7 +56,7 @@ pub fn validate_face_target_json(target: &Value) -> Result<()> {
     if !(4..=5).contains(&fields.len())
         || fields.keys().any(|key| !["body", "origin_feature", "name", "point", "certificate"].contains(&key.as_str()))
         || fields.get("body").and_then(Value::as_str).is_none_or(|body| body.is_empty() || body.len() > 128)
-        || fields.get("name").and_then(Value::as_str).is_none_or(|name| name.is_empty() || name.len() > 512)
+        || fields.get("name").and_then(Value::as_str).is_none_or(|name| name.is_empty() || name.len() > MAX_REFERENCE_NAME_BYTES)
         || fields.get("origin_feature").and_then(Value::as_u64).is_none_or(|id| id == 0)
         || fields.get("point").and_then(Value::as_array).is_none_or(|point| {
             point.len() != 3 || point.iter().any(|value| value.as_f64().is_none_or(|value| !value.is_finite() || value.abs() > 1e9))
@@ -91,7 +94,7 @@ pub fn validate_styles_json(value: &Value) -> Result<()> {
                 if !certificate.is_null()
                     && (face.get("strict_name").and_then(Value::as_bool) != Some(true)
                         || face.get("body").and_then(Value::as_str).is_none_or(|body| body.is_empty() || body.len() > 128)
-                        || face.get("name").and_then(Value::as_str).is_none_or(|name| name.is_empty() || name.len() > 512)
+                        || face.get("name").and_then(Value::as_str).is_none_or(|name| name.is_empty() || name.len() > MAX_REFERENCE_NAME_BYTES)
                         || face.get("point").and_then(Value::as_array).is_none_or(|point| {
                             point.len() != 3 || point.iter().any(|value| value.as_f64().is_none_or(|value| !value.is_finite() || value.abs() > 1e9))
                         }))

crates/doc/src/construct.rs

@@ -207,7 +207,7 @@ fn edge_circle(b: &ModelBody, index: usize, pts: &[Vec3]) -> Option<(Vec3, Vec3)
 }
 
 /// The most edge names a vertex reference keeps.
-const MAX_VERTEX_EDGES: usize = 16;
+pub(crate) const MAX_VERTEX_EDGES: usize = 16;
 
 /// Where the edges named `names` meet: the end every one of them has, nearest `at` (two edges
 /// between the same two vertices share both). `None` when an edge is gone or they share no end.
@@ -230,17 +230,32 @@ fn named_vertex(st: &ModelState, at: Vec3, names: &[String]) -> Option<Vec3> {
             })
         })
         .collect::<Option<_>>()?;
-    let (first, rest) = ends.split_first()?;
-    let tol = |p: Vec3| 1e-6 * (1.0 + p.len());
-    first
-        .iter()
-        .copied()
-        .filter(|p| p.is_finite() && rest.iter().all(|e| e.iter().any(|q| q.dist(*p) <= tol(*p))))
-        .min_by(|p, q| p.dist(at).total_cmp(&q.dist(at)))
+    shared_ends(&ends).into_iter().min_by(|p, q| p.dist(at).total_cmp(&q.dist(at)))
+}
+
+/// How near two points of a body are the same point: a millionth of their distance from the
+/// origin, and at least a millionth of a millimetre.
+pub(crate) fn point_tolerance(p: Vec3) -> f64 {
+    1e-6 * (1.0 + p.len())
+}
+
+/// Where edges meet: the ends in `ends[0]` that every other list in `ends` has too (to
+/// [`point_tolerance`]), each once. Empty when they share none.
+pub(crate) fn shared_ends<E: AsRef<[Vec3]>>(ends: &[E]) -> Vec<Vec3> {
+    let tol = point_tolerance;
+    let Some((first, rest)) = ends.split_first() else { return Vec::new() };
+    let mut shared: Vec<Vec3> = Vec::new();
+    for p in first.as_ref().iter().copied() {
+        let everywhere = rest.iter().all(|e| e.as_ref().iter().any(|q| q.dist(p) <= tol(p)));
+        if p.is_finite() && everywhere && !shared.iter().any(|q| q.dist(p) <= tol(p)) {
+            shared.push(p);
+        }
+    }
+    shared
 }
 
 /// A polyline that is straight: its line.
-fn as_line(pts: &[Vec3]) -> Option<(Vec3, Vec3)> {
+pub(crate) fn as_line(pts: &[Vec3]) -> Option<(Vec3, Vec3)> {
     let (a, b) = (*pts.first()?, *pts.last()?);
     let d = (b - a).normalized()?;
     let len = (b - a).len();
@@ -248,7 +263,7 @@ fn as_line(pts: &[Vec3]) -> Option<(Vec3, Vec3)> {
 }
 
 /// A polyline on a circle: (centre, unit normal, radius).
-fn as_circle(pts: &[Vec3]) -> Option<(Vec3, Vec3, f64)> {
+pub(crate) fn as_circle(pts: &[Vec3]) -> Option<(Vec3, Vec3, f64)> {
     let n = pts.len();
     if n < 4 {
         return None;

crates/doc/src/display_units.rs

@@ -1,30 +1,31 @@
 //! The existing length display policy, shared by windowed and headless consumers.
 //!
-//! Values are stored in millimetres and displayed in the five design units. Unknown unit
-//! names retain the millimetre fallback; expression units have a separate, broader vocabulary.
-//! These functions format values, not validate them: non-finite inputs retain Rust's `NaN`,
-//! `inf` and `-inf` text. Callers that require finite measurements must validate them first.
+//! Values are stored in millimetres and displayed in any length unit of the expression unit table
+//! ([`UNITS`]): a design's five units and the others a drawing may give its measurements in. One
+//! table for both, so every length unit a design or a drawing accepts shows its own numbers. Other
+//! names retain the millimetre fallback. These functions format values, not validate them:
+//! non-finite inputs retain Rust's `NaN`, `inf` and `-inf` text. Callers that require finite
+//! measurements must validate them first.
 
 use serde::{Deserialize, Serialize};
 
+use crate::expr::{Kind, UNITS};
 use crate::{DocError, Result, expr};
 
-/// Units per millimetre and the unit's name. Unknown names use millimetres.
+/// Units per millimetre and the unit's name, for a length unit of [`UNITS`]. Other names use
+/// millimetres.
 pub fn unit_scale(units: &str) -> (f64, &'static str) {
-    match units {
-        "cm" => (0.1, "cm"),
-        "m" => (0.001, "m"),
-        "in" => (1.0 / 25.4, "in"),
-        "ft" => (1.0 / 304.8, "ft"),
-        _ => (1.0, "mm"),
+    match UNITS.iter().find(|(name, kind, _)| *name == units && *kind == Kind::Length) {
+        Some(&(name, _, mm)) => (1.0 / mm, name),
+        None => (1.0, "mm"),
     }
 }
 
-/// Inch labels retain a meaningful fourth digit without promoting floating-point noise.
-/// `value` is already converted to the requested display unit, not a millimetre value.
+/// Inch labels (`in` or `inch`) retain a meaningful fourth digit without promoting floating-point
+/// noise. `value` is already converted to the requested display unit, not a millimetre value.
 pub fn length_precision(value: f64, units: &str, decimals: u8) -> usize {
     let base = usize::from(decimals.min(8));
-    if units != "in" {
+    if unit_scale(units).0 != unit_scale("in").0 {
         return base;
     }
     let needs_four = ((value * 10_000.0).round() - (value * 1000.0).round() * 10.0).abs() >= 0.5;
@@ -182,6 +183,7 @@ fn grouped_digits(text: &mut String, digits: &str, integer: bool, groups: bool)
 #[cfg(test)]
 mod tests {
     use super::{format_length, length_number, length_precision, unit_scale};
+    use crate::expr::{Kind, UNITS};
 
     #[test]
     fn all_design_units_keep_bare_and_suffixed_labels() {
@@ -245,9 +247,26 @@ mod tests {
         assert_eq!(format_length(-0.0, "in", 2), "-0.000 in");
     }
 
+    #[test]
+    fn every_length_unit_shows_its_own_numbers() {
+        // Each length unit of the expression table, which a design's units and a drawing's unit
+        // come from, never millimetres unless it is millimetres.
+        for &(name, kind, mm) in UNITS {
+            if kind != Kind::Length {
+                continue;
+            }
+            assert_eq!(unit_scale(name), (1.0 / mm, name), "{name}");
+            let bare = if matches!(name, "in" | "inch") { "12.500" } else { "12.50" };
+            assert_eq!(length_number(12.5 * mm, name, 2), bare, "{name}");
+            assert_eq!(format_length(12.5 * mm, name, 2), format!("{bare} {name}"), "{name}");
+        }
+        assert_eq!(length_number(25.4 * 1.2345, "inch", 0), "1.2345");
+    }
+
     #[test]
     fn unknown_display_units_keep_the_millimetre_fallback() {
-        for units in ["", "inch", " in ", "IN", "unsupported"] {
+        // Names that aren't a length unit of the expression table, angles included.
+        for units in ["", " in ", "IN", "unsupported", "deg", "rad"] {
             assert_eq!(unit_scale(units), (1.0, "mm"), "{units}");
             assert_eq!(length_number(25.4, units, 2), "25.40", "{units}");
             assert_eq!(format_length(25.4, units, 2), "25.40 mm", "{units}");

crates/doc/src/document.rs

@@ -504,12 +504,7 @@ impl EmbossFace {
 
     /// Resolve this exact placement without expanding every assembly instance.
     pub fn body_frame(&self, doc: &Document, body: &crate::ModelBody) -> Result<crate::Mat> {
-        let owner = doc.model_body_component(body);
-        let mut frame = Self::component_frame(doc, owner, &self.path)?;
-        if let Some(offset) = doc.model_body_offset(body) {
-            frame = crate::mat_mul(&frame, offset);
-        }
-        Ok(frame)
+        doc.body_frame_at(body, &self.path)
     }
 
     /// Resolve one saved component path without expanding other occurrences.
@@ -3223,6 +3218,12 @@ pub struct Document {
     /// it saves.
     #[serde(default, skip_serializing_if = "Visibility::is_empty")]
     pub visibility: Visibility,
+    /// The design's drawings (#3890), by name, then id ([`crate::drawing::in_design`]), each behind
+    /// its own `Arc`, so an undo step shares every drawing it didn't change. Each is read by its own
+    /// family's rules ([`crate::format::read`]), never as a field of the design; a container keeps
+    /// each in its own entry.
+    #[serde(skip_deserializing, skip_serializing_if = "Vec::is_empty")]
+    pub drawings: Vec<std::sync::Arc<crate::drawing::Drawing>>,
 }
 
 /// The browser's view of a design: items and folders hidden or shown, sketch profiles and
@@ -3510,6 +3511,7 @@ impl Document {
             browser_order: Default::default(),
             named_views: Vec::new(),
             visibility: Visibility::default(),
+            drawings: Vec::new(),
         }
     }
 
@@ -3650,29 +3652,38 @@ impl Document {
         *self == normalized
     }
 
-    /// Only part properties changed (the fields `with_part_properties_of` names): nothing to
-    /// evaluate. The same whole-Document proof as [`Document::differs_only_in_render`].
+    /// Only part properties changed (the fields `with_part_properties_of` names), and perhaps
+    /// drawings with them, as placing a parts list saves its numbers: nothing to evaluate. The
+    /// same whole-Document proof as [`Document::differs_only_in_render`].
     pub fn differs_only_in_part_properties(&self, previous: &Document) -> bool {
         previous.with_part_properties_of(self).is_some_and(|normalized| normalized == *self)
     }
 
     /// This design with `other`'s part properties, or `None` when they are this design's
     /// already (then nothing is copied). The part properties are the fields that change no
-    /// geometry: the design's metadata, and each component's metadata and free properties. A
-    /// field that joins them is compared and copied here, and nowhere else.
+    /// geometry: the design's metadata, each component's metadata and free properties, each
+    /// placement's bill of materials type and the saved item numbers. A field that joins them is
+    /// compared and copied here, and nowhere else.
     fn with_part_properties_of(&self, other: &Document) -> Option<Document> {
         let same = self.metadata == other.metadata
-            && self.components.iter().zip(&other.components).all(|(c, o)| c.metadata == o.metadata && c.properties == o.properties);
+            && self.components.iter().zip(&other.components).all(|(c, o)| c.metadata == o.metadata && c.properties == o.properties)
+            && self.occurrences.iter().zip(&other.occurrences).all(|(c, o)| c.bom_type == o.bom_type)
+            && self.assembly.item_numbers == other.assembly.item_numbers;
         if same {
             return None;
         }
         let mut out = self.clone();
         out.metadata.clone_from(&other.metadata);
-        // Paired by position: if the components themselves differ, so do the designs.
+        out.assembly.item_numbers.clone_from(&other.assembly.item_numbers);
+        out.drawings.clone_from(&other.drawings);
+        // Paired by position: if the components or placements themselves differ, so do the designs.
         for (c, o) in out.components.iter_mut().zip(&other.components) {
             c.metadata.clone_from(&o.metadata);
             c.properties.clone_from(&o.properties);
         }
+        for (c, o) in out.occurrences.iter_mut().zip(&other.occurrences) {
+            c.bom_type = o.bom_type;
+        }
         Some(out)
     }
 
@@ -3688,6 +3699,32 @@ impl Document {
         *self == normalized
     }
 
+    /// Only drawings changed: nothing to evaluate, as a drawing reads the model and never changes
+    /// it. The same whole-Document proof as [`Document::differs_only_in_render`]; a model edit
+    /// shares every drawing's `Arc`, so it costs nothing here.
+    pub fn differs_only_in_drawings(&self, previous: &Document) -> bool {
+        let shared =
+            self.drawings.len() == previous.drawings.len() && self.drawings.iter().zip(&previous.drawings).all(|(a, b)| std::sync::Arc::ptr_eq(a, b));
+        if shared || self.drawings == previous.drawings {
+            return false;
+        }
+        let mut normalized = previous.clone();
+        normalized.drawings = self.drawings.clone();
+        *self == normalized
+    }
+
+    /// The design's drawing `id`.
+    pub fn drawing(&self, id: u64) -> Option<&std::sync::Arc<crate::drawing::Drawing>> {
+        self.drawings.iter().find(|d| d.id == id)
+    }
+
+    /// Put `drawing` in, in place of the one with its id if there is one, in the drawings' order.
+    pub fn put_drawing(&mut self, drawing: std::sync::Arc<crate::drawing::Drawing>) {
+        self.drawings.retain(|d| d.id != drawing.id);
+        self.drawings.push(drawing);
+        crate::drawing::sort(&mut self.drawings);
+    }
+
     /// The colour a body is shown and exported in (sRGB as 0–1 fractions): its appearance,
     /// else its component's, else its material's look, else the colour it was imported with.
     /// (Faces may have their own: `face_looks`.)
@@ -3798,12 +3835,12 @@ impl Document {
     }
 
     pub fn legacy_body_component(&self, body: &str, feature: u64) -> u64 {
-        self.body_components.get(body).copied().unwrap_or_else(|| self.feature(feature).map(|f| f.component).unwrap_or(0))
+        self.legacy_body_component_with(body, feature, |f| self.feature(f).map(|f| f.component))
     }
 
     /// Ownership in this evaluated timeline state, rather than a later transfer.
     pub fn model_body_component(&self, body: &crate::ModelBody) -> u64 {
-        if body.transferred || body.source_name.is_some() { body.component } else { self.legacy_body_component(&body.name, body.feature) }
+        self.model_body_component_with(body, |f| self.feature(f).map(|f| f.component))
     }
 
     /// [`Document::model_body_component`] of every body of `state`, in its order, with the
@@ -3828,17 +3865,25 @@ impl Document {
     /// in one pass: the timeline is looked up once, not once per body.
     pub fn body_owners(&self, state: &crate::ModelState) -> std::collections::HashSet<u64> {
         let features: std::collections::HashMap<u64, u64> = self.features.iter().rev().map(|f| (f.id, f.component)).collect();
-        state
-            .bodies
-            .iter()
-            .map(|b| {
-                if b.transferred || b.source_name.is_some() {
-                    b.component
-                } else {
-                    self.body_components.get(&b.name).copied().unwrap_or_else(|| features.get(&b.feature).copied().unwrap_or(0))
-                }
-            })
-            .collect()
+        state.bodies.iter().map(|b| self.model_body_component_with(b, |f| features.get(&f).copied())).collect()
+    }
+
+    /// [`Document::model_body_component`]'s rule, written once: a body the evaluation transferred,
+    /// or placed from a source, keeps the component it was given; any other is
+    /// [`Document::legacy_body_component`]'s. `feature_component` finds a feature's component:
+    /// the timeline for one body, a map built once for many ([`Document::body_owners`]).
+    fn model_body_component_with(&self, body: &crate::ModelBody, feature_component: impl FnOnce(u64) -> Option<u64>) -> u64 {
+        if body.transferred || body.source_name.is_some() {
+            body.component
+        } else {
+            self.legacy_body_component_with(&body.name, body.feature, feature_component)
+        }
+    }
+
+    /// [`Document::legacy_body_component`]'s rule, written once: the component the body was moved
+    /// to, else its feature's, else the root.
+    fn legacy_body_component_with(&self, body: &str, feature: u64, feature_component: impl FnOnce(u64) -> Option<u64>) -> u64 {
+        self.body_components.get(body).copied().unwrap_or_else(|| feature_component(feature).unwrap_or(0))
     }
 
     /// Recorded transfers already converted geometry into the new local frame.
@@ -3846,6 +3891,17 @@ impl Document {
         if body.transferred { None } else { self.body_offsets.get(&body.name) }
     }
 
+    /// The frame `body`'s geometry is in, placed through the occurrence path `path` (empty: its
+    /// component's own placement): the placement, then the body's offset. One placement, without
+    /// expanding every assembly instance.
+    pub fn body_frame_at(&self, body: &crate::ModelBody, path: &[u64]) -> Result<crate::Mat> {
+        let mut frame = EmbossFace::component_frame(self, self.model_body_component(body), path)?;
+        if let Some(offset) = self.model_body_offset(body) {
+            frame = crate::mat_mul(&frame, offset);
+        }
+        Ok(frame)
+    }
+
     /// Add a component under `parent` and return its id.
     pub fn add_component(&mut self, name: Option<&str>, parent: u64) -> Result<u64> {
         if parent != 0 && !self.components.iter().any(|c| c.id == parent) {

crates/doc/src/drawing.rs

@@ -1,18 +1,33 @@
-//! A drawing (#3890): sheets of paper that draw designs saved in their own files. A drawing is a
-//! file of its own, `"format": "solidcraft-drawing/N"`, versioned by the same code as designs
-//! ([`DRAWING`]); format 1 is this record.
+//! A drawing (#3890): sheets of paper that draw a design. A drawing lives in the file of the design
+//! it draws ([`Document::drawings`](crate::Document::drawings)): a design container keeps each in
+//! its own entry, a plain JSON design inline. Each is a record of its own family,
+//! `"format": "solidcraft-drawing/N"`, versioned by the same code as designs ([`DRAWING`]), so a
+//! change to the record is a drawing change, not a design one.
 //!
-//! - **Sources** are the designs it draws: an id and the design file's path, relative to the
-//!   drawing's folder once the drawing is saved, else as given, with `/` between folders (a linked
-//!   design's [`DesignLink`](crate::DesignLink) rule). What a design was when the drawing last saw
-//!   it is not saved here.
-//! - **Sheets**: the paper, a copy of its drawing border, the resolution its pictures are rendered
-//!   at, the component it documents, and whether it is left out of the sheet count or of printing.
-//!   The border is a copy of the profile it was made with, never a name, so a later built-in never
-//!   changes a saved drawing.
+//! - Each drawing has an **id**, unique among its design's drawings, and a design lists its
+//!   drawings by name, then id ([`in_design`]): nothing to merge when two people add drawings.
+//! - **Sources** are the designs it draws. For now a drawing draws the design it is in: at most one
+//!   source, an id and nothing else. What the design was when the drawing last saw it is not saved
+//!   here.
+//! - **Sheets**: the paper, a copy of its drawing border and of its title block with the text typed
+//!   over its cells' values, the resolution its pictures are rendered at, the component it
+//!   documents, and whether it is left out of the sheet count or of printing. The border and the
+//!   block are copies of what they were made with, never names, so a later built-in never changes a
+//!   saved drawing.
 //! - **Units** follow each view's design or are one length unit for the whole drawing. The
 //!   **language** is the content's, a BCP 47 tag chosen when the drawing is made, whatever the
 //!   interface's is. **Properties** follow [`Metadata`]'s rules.
+//! - The **font** its text is set in: a font family's name, never a file, so the drawing travels
+//!   (none: the built-in font; [`solidcraft_sketch::check_family`]).
+//! - **Views** of its designs on its sheets, base and projected ([`view`]), and the **projection**
+//!   (first or third angle) every projected view follows.
+//! - **Dimensions** on its views, each measuring named corners or edges of the view's model
+//!   ([`dimension`]).
+//! - **Balloons** on its views, each pointing at a placed part by a named edge of it ([`balloon`]).
+//! - **Images** on its sheets, each file kept once however many places it sits ([`image`]).
+//! - **Tables** on its sheets: parts lists and revision tables ([`table`]).
+//! - **Revisions**: one revision record for the whole drawing ([`RevisionRecord`]), its rows in the
+//!   order they were added, the newest last.
 //!
 //! The rules, which every later kind of record (views, annotations, tables) keeps too:
 //! - Every object has an id of [`crate::ids`]: random, so objects added side by side never take
@@ -20,35 +35,59 @@
 //!   never gives a removed object's id again ([`Drawing::allocate_id`]).
 //! - Every reference between records is an id and must resolve: a file with one that doesn't is
 //!   damaged and refused, never patched.
-//! - 1 to [`MAX_SHEETS`] sheets and at most [`MAX_SOURCES`] sources; names of 1 to
-//!   [`MAX_NAME_BYTES`] bytes; paths of 1 to [`MAX_PATH_BYTES`] bytes, without NUL.
+//! - 1 to [`MAX_SHEETS`] sheets; names of 1 to [`MAX_NAME_BYTES`] bytes.
 //! - Nothing derived is saved, and a drawing always saves as the same bytes: fields in their
-//!   order, maps sorted.
+//!   order, maps sorted, and lists of records in a fixed order (sheets as arranged; later
+//!   records by id), never the order they were added in. Records listed by id read in that order
+//!   whatever order a file lists them in: the order means nothing, so it is never damage.
 //! - A later change to the record is one file in `src/drawing/format/pending/` (its README).
 //!
-//! [`Drawing::from_json`] reads a file in this order: at most [`MAX_DRAWING_BYTES`] of text, the
-//! family's format check, every number in range, the upgrade, the typed record, then
-//! [`Drawing::validate`].
+//! [`Drawing::from_json`] reads a drawing in this order: at most [`MAX_DRAWING_BYTES`] of text,
+//! the family's format check, every number in range, the upgrade, the typed record with its views,
+//! dimensions, balloons, images and notes by id, then [`Drawing::validate`] and each image's file
+//! ([`Drawing::check_image_files`]); [`Drawing::from_value`] the same from the format check on.
 
-use std::collections::BTreeSet;
+use std::borrow::Cow;
+use std::collections::{BTreeMap, BTreeSet};
 use std::sync::Arc;
 
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
+use solidcore_record::Vec2;
+use solidcraft_geom::Aabb2;
+use solidcraft_geom::cell::Projection;
 use solidcraft_geom::drawing_sheet::{self, DrawingBorderProfile};
+use solidcraft_geom::revision::RevisionRecord;
+use solidcraft_geom::title_block::TitleBlock;
 
 use crate::format::DRAWING;
 use crate::ids::{self, IdSource};
 use crate::{DocError, Metadata, Result, expr};
 
+pub mod balloon;
+pub mod by_id;
+pub mod dimension;
+pub mod fields;
+pub mod image;
+pub mod note;
+pub mod table;
+pub mod template;
+pub mod view;
+
+use balloon::Balloon;
+use by_id::ById;
+use dimension::Dimension;
+use image::{ImageFile, SheetImage};
+use note::{Anchor, Note};
+use table::SheetTable;
+use view::View;
+
+/// The most drawings a design may hold.
+pub const MAX_DRAWINGS: usize = 1000;
 /// The most sheets a drawing may have.
 pub const MAX_SHEETS: usize = 1000;
-/// The most designs a drawing may draw.
-pub const MAX_SOURCES: usize = 64;
 /// The longest name of a drawing or a sheet, in bytes.
 pub const MAX_NAME_BYTES: usize = 256;
-/// The longest path to a design, in bytes.
-pub const MAX_PATH_BYTES: usize = 4096;
 /// The longest language tag: what RFC 5646 asks every reader to take (§4.4.1).
 pub const MAX_LANGUAGE_CHARS: usize = 35;
 /// The largest drawing read, as JSON text.
@@ -72,29 +111,60 @@ pub struct Drawing {
     /// otherwise.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub format_pending: Vec<String>,
+    /// Unique among its design's drawings: a design container's entry for it is named by it.
+    #[serde(with = "crate::ids")]
+    pub id: u64,
     pub name: String,
-    /// The designs the drawing draws.
+    /// The designs the drawing draws: for now at most one, the design it is in.
     pub sources: Vec<Source>,
-    /// The drawing's properties and other tools' data, kept as they are.
-    #[serde(default, skip_serializing_if = "Metadata::is_empty")]
-    pub properties: Metadata,
+    /// The drawing's properties and other tools' data, kept as they are, behind an `Arc` as the
+    /// sheets are, so an undo step shares them while they don't change.
+    #[serde(default, skip_serializing_if = "no_properties")]
+    pub properties: Arc<Metadata>,
     #[serde(default)]
     pub units: Units,
+    /// First or third angle: what every projected view shows, and the title block's symbol.
+    #[serde(default)]
+    pub projection: Projection,
     /// The language of the drawing's content, a BCP 47 tag (`en-GB`).
     pub language: String,
+    /// The font family its text is set in, by name; empty: the built-in font.
+    #[serde(default, skip_serializing_if = "String::is_empty")]
+    pub font: String,
     /// In order, each behind its own `Arc`, so an undo step shares every sheet it didn't change.
     pub sheets: Vec<Arc<Sheet>>,
+    /// By id ([`Drawing::add_views`]), each behind its own `Arc`, as the sheets are.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub views: Vec<Arc<View>>,
+    /// By id ([`Drawing::add_dimensions`]), each behind its own `Arc`, as the views are.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub dimensions: Vec<Arc<Dimension>>,
+    #[serde(default, skip_serializing_if = "ById::is_empty")]
+    pub balloons: ById<Balloon>,
+    /// The image files, once each however many places they sit.
+    #[serde(default, skip_serializing_if = "ById::is_empty")]
+    pub images: ById<ImageFile>,
+    /// Where they sit on the sheets.
+    #[serde(default, skip_serializing_if = "ById::is_empty")]
+    pub sheet_images: ById<SheetImage>,
+    /// The saved tables on its sheets: parts lists and revision tables.
+    #[serde(default, skip_serializing_if = "ById::is_empty")]
+    pub tables: ById<SheetTable>,
+    /// The notes on its sheets and in its views.
+    #[serde(default, skip_serializing_if = "ById::is_empty")]
+    pub notes: ById<Note>,
+    /// Behind an `Arc` as the sheets are, so an undo step shares it while it doesn't change.
+    #[serde(default, skip_serializing_if = "no_revisions")]
+    pub revisions: Arc<RevisionRecord>,
 }
 
-/// A design the drawing draws.
+/// A design the drawing draws: the design the drawing is in. Views and sheets name it by its id,
+/// so a drawing of other designs can add sources of another kind later.
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(deny_unknown_fields)]
 pub struct Source {
     #[serde(with = "crate::ids")]
     pub id: u64,
-    /// The design file: relative to the drawing's folder once the drawing is saved, else as given
-    /// (`/` separates folders).
-    pub path: String,
 }
 
 /// The length unit a drawing gives its measurements in.
@@ -119,6 +189,14 @@ pub struct Sheet {
     pub sheet: drawing_sheet::Sheet,
     /// A copy of the drawing border's profile (`None`: no drawing border).
     pub border: Option<DrawingBorderProfile>,
+    /// A copy of its title block's definition (`None`: no title block), on the drawing border's
+    /// lower-right corner, so only a sheet with a border has one.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub title_block: Option<TitleBlock>,
+    /// Text shown in place of a title block cell's value, by the cell's name: the value is still
+    /// worked out, so it can be shown beside it.
+    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+    pub title_block_overrides: BTreeMap<String, String>,
     /// The resolution its pictures (its shaded views) are rendered at, in dots per inch.
     #[serde(default = "default_dpi")]
     pub dpi: f64,
@@ -149,49 +227,150 @@ pub struct Excluded {
     pub print: bool,
 }
 
+impl Sheet {
+    /// Where the sheet's drawing goes, in paper millimetres: inside its drawing border, or the
+    /// whole paper when it has none. Nothing on a sheet is saved against its border, so a change
+    /// of paper regrows the border and its zones by itself.
+    pub fn drawing_space(&self) -> Result<Aabb2> {
+        match &self.border {
+            Some(border) => Ok(border.layout(&self.sheet).map_err(from_sheet)?.drawing_border),
+            None => Ok(Aabb2 { min: Vec2::ZERO, max: self.sheet.size_mm().map_err(from_sheet)? }),
+        }
+    }
+
+    /// Where its title block sits, in paper millimetres (none without one), once its drawing border
+    /// and the block on it lay out on the paper: the rule a sheet is held to, as drawing them uses it.
+    pub fn title_block_outline(&self) -> Result<Option<Aabb2>> {
+        let border = self.border.as_ref().map(|border| border.layout(&self.sheet)).transpose().map_err(from_sheet)?;
+        let Some(block) = &self.title_block else { return Ok(None) };
+        let border = border.ok_or_else(|| DocError::Invalid("its title block sits on a drawing border, and it has none".into()))?;
+        Ok(Some(block.layout(&border).map_err(|e| DocError::Invalid(e.to_string()))?.outline))
+    }
+
+    /// Gives the sheet `block` (`None`: no title block). Text typed over a cell stays while `block`
+    /// has a text cell of that name; answers the cells whose typed text is dropped.
+    pub fn set_title_block(&mut self, block: Option<TitleBlock>) -> Vec<String> {
+        let kept = |name: &String| fields::overridable(block.as_ref(), name);
+        let lost = self.title_block_overrides.keys().filter(|name| !kept(name)).cloned().collect();
+        self.title_block_overrides.retain(|name, _| kept(name));
+        self.title_block = block;
+        lost
+    }
+}
+
+/// What is on one of a drawing's sheets ([`Drawing::on_sheet`]), each kind by id.
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
+pub struct OnSheet {
+    pub views: Vec<u64>,
+    /// The dimensions in its views.
+    pub dimensions: Vec<u64>,
+    /// The balloons in its views.
+    pub balloons: Vec<u64>,
+    /// The images placed on it.
+    pub images: Vec<u64>,
+    /// The revision tags on it.
+    pub tags: Vec<u64>,
+    /// The tables on it.
+    pub tables: Vec<u64>,
+    /// The notes on it and in its views.
+    pub notes: Vec<u64>,
+}
+
+impl OnSheet {
+    /// Nothing is on the sheet.
+    pub fn is_empty(&self) -> bool {
+        self.views.is_empty()
+            && self.dimensions.is_empty()
+            && self.balloons.is_empty()
+            && self.images.is_empty()
+            && self.tags.is_empty()
+            && self.tables.is_empty()
+            && self.notes.is_empty()
+    }
+}
+
 fn default_dpi() -> f64 {
     DEFAULT_DPI
 }
 
 impl Drawing {
     /// A drawing of no designs yet, named `name` and written in `language`, with one sheet named
-    /// `sheet`: the paper `paper` with a copy of `border`, its id from `id_source`.
+    /// `sheet`: the paper `paper` with a copy of `border`. Its id, and then its sheet's, come from
+    /// `id_source`, the drawing's differing from every one in `taken` (its design's drawings').
     pub fn new(
         name: &str,
         language: &str,
         sheet: &str,
         paper: drawing_sheet::Sheet,
         border: Option<DrawingBorderProfile>,
+        taken: &BTreeSet<u64>,
         id_source: &mut IdSource,
     ) -> Result<Drawing> {
-        let id = id_source.next(&BTreeSet::new())?;
-        let first = Sheet { id, name: sheet.into(), sheet: paper, border, dpi: DEFAULT_DPI, documents: None, excluded: Excluded::default() };
+        let id = id_source.next(taken)?;
+        let sheet_id = id_source.next(&BTreeSet::from([id]))?;
+        let first = Sheet {
+            id: sheet_id,
+            name: sheet.into(),
+            sheet: paper,
+            border,
+            title_block: None,
+            title_block_overrides: BTreeMap::new(),
+            dpi: DEFAULT_DPI,
+            documents: None,
+            excluded: Excluded::default(),
+        };
         let drawing = Drawing {
             format: DRAWING.format_string(DRAWING.current()),
             format_pending: DRAWING.pending_names(),
+            id,
             name: name.into(),
             sources: Vec::new(),
-            properties: Metadata::default(),
+            properties: Arc::default(),
             units: Units::default(),
+            projection: Projection::default(),
             language: language.into(),
+            font: String::new(),
             sheets: vec![Arc::new(first)],
+            views: Vec::new(),
+            dimensions: Vec::new(),
+            balloons: ById::default(),
+            images: ById::default(),
+            sheet_images: ById::default(),
+            tables: ById::default(),
+            notes: ById::default(),
+            revisions: Arc::default(),
         };
         drawing.validate()?;
         Ok(drawing)
     }
 
-    /// Read a drawing file's JSON (any format this build knows; older ones are upgraded). A file
+    /// Read a drawing's JSON (any format this build knows; older ones are upgraded). A drawing
     /// that breaks a rule of the record is damaged and refused, never patched.
     pub fn from_json(s: &str) -> Result<Drawing> {
         if s.len() > MAX_DRAWING_BYTES {
             return Err(DocError::Invalid(format!("drawing too large (at most {} MiB)", MAX_DRAWING_BYTES >> 20)));
         }
-        let mut v: Value = serde_json::from_str(s).map_err(|e| DocError::Invalid(format!("not a SolidCraft drawing: {e}")))?;
+        let v: Value = serde_json::from_str(s).map_err(|e| DocError::Invalid(format!("not a SolidCraft drawing: {e}")))?;
+        Drawing::from_value(v)
+    }
+
+    /// Read a drawing from its JSON value, as a plain JSON design holds it: [`Drawing::from_json`]
+    /// once the text is parsed.
+    pub fn from_value(mut v: Value) -> Result<Drawing> {
         let (version, applied) = DRAWING.take_version(&mut v)?;
         DRAWING.check_numbers(&v, "properties")?;
         DRAWING.upgrade(&mut v, version, applied.as_deref())?;
-        let d: Drawing = serde_json::from_value(v).map_err(damaged)?;
+        let mut d: Drawing = serde_json::from_value(v).map_err(damaged)?;
+        let (views, dimensions) = (std::mem::take(&mut d.views), std::mem::take(&mut d.dimensions));
+        d.add_views(views);
+        d.add_dimensions(dimensions);
+        d.balloons.put_in_order();
+        d.images.put_in_order();
+        d.sheet_images.put_in_order();
+        d.tables.put_in_order();
+        d.notes.put_in_order();
         d.validate().map_err(damaged)?;
+        d.check_image_files().map_err(damaged)?;
         Ok(Drawing { format: DRAWING.format_string(DRAWING.current()), format_pending: DRAWING.pending_names(), ..d })
     }
 
@@ -211,21 +390,105 @@ impl Drawing {
         id_source.next(&self.ids().collect())
     }
 
+    /// The position of the sheet `named` names: by id, else by a name only one sheet has.
+    pub fn sheet_index(&self, named: &str) -> Result<usize> {
+        if let Some(i) = ids::decode(named).and_then(|id| self.sheets.iter().position(|s| s.id == id)) {
+            return Ok(i);
+        }
+        let mut called = self.sheets.iter().enumerate().filter(|(_, s)| s.name == named).map(|(i, _)| i);
+        match (called.next(), called.next()) {
+            (Some(i), None) => Ok(i),
+            (Some(_), Some(_)) => Err(DocError::Invalid(format!("more than one sheet is called `{named}`: give its id"))),
+            (None, _) => Err(DocError::Invalid(format!("no sheet `{named}`"))),
+        }
+    }
+
+    /// Whether `id` names an object a sheet shows: a view, a dimension or a balloon.
+    pub fn has_object(&self, id: u64) -> bool {
+        self.view(id).is_some() || self.dimension(id).is_some() || self.balloons.by_id(id).is_some() || self.notes.by_id(id).is_some()
+    }
+
+    /// What is on sheet `id`: its views and the dimensions and balloons in them, and the images placed on it.
+    /// Each later kind of record on a sheet adds its own here, and goes with the sheet
+    /// ([`Drawing::remove_sheet`]).
+    pub fn on_sheet(&self, id: u64) -> OnSheet {
+        // The views are listed by id, so the sheet's are too, and so are its images, revision tags, tables and notes.
+        let mut on = self.with_contents(self.views.iter().filter(|v| v.sheet == id).map(|v| v.id).collect());
+        on.images = self.sheet_images.iter().filter(|i| i.sheet == id).map(|i| i.id).collect();
+        on.tags = self.revisions.tags().iter().filter(|t| t.sheet == id).map(|t| t.id).collect();
+        on.tables = self.tables.iter().filter(|t| t.sheet == id).map(|t| t.id).collect();
+        let in_views = |n: &Note| n.anchor.view().is_some_and(|v| on.views.binary_search(&v).is_ok());
+        on.notes = self.notes.iter().filter(|n| n.anchor == Anchor::Sheet(id) || in_views(n)).map(|n| n.id).collect();
+        on
+    }
+
+    /// `views`, listed by id, with the dimensions and balloons in them. An image sits on a sheet, never in a
+    /// view, so there are none.
+    pub fn with_contents(&self, views: Vec<u64>) -> OnSheet {
+        let dimensions = self.dimensions.iter().filter(|d| views.binary_search(&d.view).is_ok()).map(|d| d.id).collect();
+        let balloons = self.balloons.iter().filter(|b| views.binary_search(&b.view).is_ok()).map(|b| b.id).collect();
+        let notes = self.notes.iter().filter(|n| n.anchor.view().is_some_and(|v| views.binary_search(&v).is_ok())).map(|n| n.id).collect();
+        OnSheet { views, dimensions, balloons, images: Vec::new(), tags: Vec::new(), tables: Vec::new(), notes }
+    }
+
+    /// Takes sheet `id` out with everything on it ([`Drawing::on_sheet`]), and answers what that
+    /// was. A view on another sheet projected from one of its views is left without its parent,
+    /// which [`Drawing::validate`] refuses: what becomes of it is the caller's to decide first.
+    pub fn remove_sheet(&mut self, id: u64) -> OnSheet {
+        let on = self.on_sheet(id);
+        self.sheets.retain(|s| s.id != id);
+        self.remove_objects(&on);
+        on
+    }
+
+    /// Takes `objects` out, each list by id: the one rule a sheet's delete and a selection's delete
+    /// remove by, with the image files nothing uses any more. As in [`Drawing::remove_sheet`], what is
+    /// left must still keep the record's rules.
+    pub fn remove_objects(&mut self, objects: &OnSheet) {
+        self.views.retain(|v| objects.views.binary_search(&v.id).is_err());
+        self.dimensions.retain(|d| objects.dimensions.binary_search(&d.id).is_err());
+        self.balloons.retain(|b| objects.balloons.binary_search(&b.id).is_err());
+        self.sheet_images.retain(|i| objects.images.binary_search(&i.id).is_err());
+        self.drop_unused_images();
+        self.tables.retain(|t| objects.tables.binary_search(&t.id).is_err());
+        self.notes.retain(|n| objects.notes.binary_search(&n.id).is_err());
+        // A balloon outlives the list it named, and goes back to the lists it could read.
+        for balloon in self.balloons.iter_mut() {
+            if balloon.parts_list.is_some_and(|list| objects.tables.binary_search(&list).is_ok()) {
+                Arc::make_mut(balloon).parts_list = None;
+            }
+        }
+        if !objects.tags.is_empty() {
+            Arc::make_mut(&mut self.revisions).delete_tags(&objects.tags);
+        }
+    }
+
     /// Every object's id, of every kind: what a new id must differ from. Each later kind adds its
     /// own here.
     fn ids(&self) -> impl Iterator<Item = u64> {
-        self.sources.iter().map(|s| s.id).chain(self.sheets.iter().map(|s| s.id))
+        std::iter::once(self.id)
+            .chain(self.sources.iter().map(|s| s.id))
+            .chain(self.sheets.iter().map(|s| s.id))
+            .chain(self.views.iter().map(|v| v.id))
+            .chain(self.dimensions.iter().map(|d| d.id))
+            .chain(self.balloons.iter().map(|b| b.id))
+            .chain(self.images.iter().map(|i| i.id))
+            .chain(self.sheet_images.iter().map(|i| i.id))
+            .chain(self.tables.iter().map(|t| t.id))
+            .chain(self.notes.iter().map(|n| n.id))
+            .chain(self.revisions.ids())
     }
 
-    /// The record's rules (the module's notes): what reading a file checks, and what every edit
+    /// The record's rules (the module's notes): what reading a drawing checks, and what every edit
     /// keeps.
     pub fn validate(&self) -> Result<()> {
         require((1..=MAX_SHEETS).contains(&self.sheets.len()), || format!("a drawing has 1 to {MAX_SHEETS} sheets"))?;
-        require(self.sources.len() <= MAX_SOURCES, || format!("a drawing draws at most {MAX_SOURCES} designs"))?;
+        require(self.sources.len() <= 1, || "a drawing draws only the design it is in".into())?;
         check_name(&self.name, "the drawing's")?;
         require(is_language_tag(&self.language), || {
             format!("the language is not a BCP 47 tag of 2 to {MAX_LANGUAGE_CHARS} characters (such as `en` or `en-GB`)")
         })?;
+        solidcraft_sketch::check_family(&self.font).map_err(|e| DocError::Invalid(format!("the drawing's font: {e}")))?;
         if let Units::Fixed { unit } = &self.units {
             // A length unit of the expression unit table, written as the table writes it.
             let length = unit.trim() == unit.as_str() && expr::unit_info(unit).is_some_and(|(kind, _)| kind == expr::Kind::Length);
@@ -236,25 +499,38 @@ impl Drawing {
             require(id != 0, || "an object has the id 0, which is never one".into())?;
             require(seen.insert(id), || format!("two objects have the id {}", ids::encode(id)))?;
         }
-        for source in &self.sources {
-            let path = &source.path;
-            require(!path.is_empty() && path.len() <= MAX_PATH_BYTES && !path.contains('\0'), || {
-                format!("source {}: a design's path is 1 to {MAX_PATH_BYTES} bytes, without NUL", ids::encode(source.id))
-            })?;
-        }
         for sheet in &self.sheets {
             self.check_sheet(sheet).map_err(|e| DocError::Invalid(format!("sheet {}: {e}", ids::encode(sheet.id))))?;
         }
-        Ok(())
+        // One record for the whole drawing until sheets keep their own (#3874).
+        require(!self.revisions.per_sheet, || "a drawing keeps one revision record for all its sheets".into())?;
+        self.revisions.validate().map_err(|e| DocError::Invalid(e.to_string()))?;
+        require(self.revisions.tags().iter().all(|t| self.sheets.iter().any(|s| s.id == t.sheet)), || {
+            "a revision tag is on one of the drawing's sheets".into()
+        })?;
+        self.check_views()?;
+        self.check_dimensions()?;
+        self.check_tables()?;
+        self.check_balloons()?;
+        self.check_images()?;
+        self.check_notes()
     }
 
     /// A sheet's own rules, and that the source it documents is one of the drawing's.
     fn check_sheet(&self, sheet: &Sheet) -> Result<()> {
         check_name(&sheet.name, "its")?;
         sheet.sheet.size_mm().map_err(from_sheet)?;
-        if let Some(border) = &sheet.border {
-            border.validate().map_err(from_sheet)?;
+        sheet.title_block_outline()?;
+        if let Some(block) = &sheet.title_block {
+            fields::check_block(block)?;
         }
+        // Each override names a text cell of its block, and its text is a cell's.
+        for name in sheet.title_block_overrides.keys() {
+            let named = || format!("its title block has no text cell `{name}` to override");
+            require(fields::overridable(sheet.title_block.as_ref(), name), named)?;
+        }
+        let texts = sheet.title_block_overrides.values().map(String::as_str);
+        solidcraft_geom::cell::check_text(texts).map_err(|e| DocError::Invalid(e.to_string()))?;
         require((MIN_DPI..=MAX_DPI).contains(&sheet.dpi), || format!("its pictures are {MIN_DPI} to {MAX_DPI} dpi"))?;
         match sheet.documents {
             Some(SheetComponent { source, .. }) => {
@@ -264,6 +540,89 @@ impl Drawing {
             None => Ok(()),
         }
     }
+
+    /// How a message names this drawing: by its name and id.
+    pub fn label(&self) -> String {
+        format!("drawing {:?} ({})", self.name, ids::encode(self.id))
+    }
+}
+
+/// A design's drawings as read, each checked on its own already: in their order (by name, then id)
+/// and keeping [`check_in_design`]'s rules.
+pub fn in_design(drawings: Vec<Drawing>) -> Result<Vec<Arc<Drawing>>> {
+    let mut drawings: Vec<_> = drawings.into_iter().map(Arc::new).collect();
+    sort(&mut drawings);
+    check_in_design(&drawings)?;
+    Ok(drawings)
+}
+
+/// Put a design's drawings in their order: by name, then id. Nothing stores the order, so two
+/// people adding drawings have nothing to merge.
+pub fn sort(drawings: &mut [Arc<Drawing>]) {
+    drawings.sort_by(|a, b| (&a.name, a.id).cmp(&(&b.name, b.id)));
+}
+
+/// The rules for a design's drawings: at most [`MAX_DRAWINGS`], and no two with one id.
+pub fn check_in_design(drawings: &[Arc<Drawing>]) -> Result<()> {
+    check_count(drawings.len())?;
+    let mut seen = BTreeSet::new();
+    drawings.iter().try_for_each(|d| take_id(&mut seen, d.id))
+}
+
+/// A drawing takes `id`, which no drawing before it in its design (`seen`) has.
+fn take_id(seen: &mut BTreeSet<u64>, id: u64) -> Result<()> {
+    require(seen.insert(id), || format!("two drawings have the id {}", ids::encode(id)))
+}
+
+/// A design of `count` drawings keeps the cap: what a reader checks before it reads any of them.
+pub fn check_count(count: usize) -> Result<()> {
+    require(count <= MAX_DRAWINGS, || format!("a design holds at most {MAX_DRAWINGS} drawings"))
+}
+
+/// Whether the drawing has no properties, so its file leaves them out.
+fn no_properties(properties: &Arc<Metadata>) -> bool {
+    properties.is_empty()
+}
+
+/// Adds `more` to `records`, each where its id puts it: the order every list of records after the
+/// sheets keeps (the module's rule), whatever order they come in.
+fn add_by_id<T>(records: &mut Vec<Arc<T>>, more: impl IntoIterator<Item = Arc<T>>, id: impl Fn(&T) -> u64) {
+    records.extend(more);
+    records.sort_by_key(|r| id(r));
+}
+
+/// Whether `records` are in the order [`add_by_id`] keeps.
+fn in_id_order<T>(records: &[Arc<T>], id: impl Fn(&T) -> u64) -> bool {
+    records.is_sorted_by_key(|r| id(r))
+}
+
+fn no_revisions(revisions: &Arc<RevisionRecord>) -> bool {
+    **revisions == RevisionRecord::default()
+}
+
+/// `doc` without the drawings that break a rule, and a line naming each one left out and the
+/// rule. Reading refuses a design whole for one such drawing, so a copy that must open again (an
+/// autosave, a crash report's design) keeps the rest: the first [`MAX_DRAWINGS`], the first of
+/// two with one id, and only those keeping their own rules and small enough to save.
+pub fn openable(doc: &crate::Document) -> (Cow<'_, crate::Document>, Vec<String>) {
+    let (mut seen, mut left_out) = (BTreeSet::new(), Vec::new());
+    let kept: Vec<_> = doc
+        .drawings
+        .iter()
+        .filter(|d| {
+            // Its own rules and its size before its id: a drawing left out takes no id from a later one.
+            let checked =
+                check_count(seen.len() + 1).and_then(|()| d.validate()).and_then(|()| d.to_json().map(drop)).and_then(|()| take_id(&mut seen, d.id));
+            checked.map_err(|e| left_out.push(format!("{} left out: {e}", d.label()))).is_ok()
+        })
+        .cloned()
+        .collect();
+    if left_out.is_empty() {
+        return (Cow::Borrowed(doc), left_out);
+    }
+    let mut doc = doc.clone();
+    doc.drawings = kept;
+    (Cow::Owned(doc), left_out)
 }
 
 /// `Ok` when `ok`, else the rule `broken` names.

crates/doc/src/drawing/balloon.rs

@@ -0,0 +1,178 @@
+//! A drawing's balloons (W26, #3874): each points at a part placed in its view's model, by an edge
+//! of it, to number that part on the drawing. A balloon saves what it points at by name, never a
+//! picked point, as a dimension does ([`super::dimension`]): when the model changes it follows the
+//! part, or says what it lost, and it never moves to another part.
+//!
+//! - **The part** it numbers is the occurrence its edge's body is placed through: the full path,
+//!   from the top. A body of the design itself is not a placed part, so no balloon points at one.
+//! - **The arrow** ends on the middle of its edge, whichever way the kernel runs the edge.
+//! - **The balloon** sits at a place on paper, in millimetres from its view's centre, so it moves
+//!   with the view and not with the model.
+//!
+//! The number a balloon shows comes from a parts list, worked out and never saved: the one it names,
+//! else its sheet's only one, else the drawing's only one ([`Drawing::parts_list_for`]). It keeps the
+//! balloon whatever becomes of the row. A parts list's editor shows how many balloons point at each of
+//! its rows ([`balloons_by_row`]), worked out the same way.
+//!
+//! The rules, beside the record's: a balloon is on one of the drawing's views; its edge reference
+//! keeps a dimension's rules, with an occurrence path of 1 to [`crate::MAX_PLACEMENT_DEPTH`] ids; its place
+//! is on paper ([`is_paper_coordinate`]); the list it names is one of the drawing's parts lists; at
+//! most [`MAX_BALLOONS`] balloons, listed by id.
+//!
+//! [`Document::resolve_balloons`] finds each balloon's edge again as a dimension's is found
+//! ([`super::dimension::Status`]): by name, strictly, and what it can't decide it says.
+
+use std::collections::HashMap;
+
+use serde::{Deserialize, Serialize};
+use solidcore_record::Vec3;
+use solidcraft_geom::drawing_view::is_paper_coordinate;
+use solidcraft_geom::paper::MAX_SIDE_MM;
+
+use super::by_id::Record;
+use super::dimension::{Lookup, ModelEdge, Status, check_edge};
+use super::table::{Kind, PartsList, SheetTable};
+use super::{Drawing, require};
+use crate::bom::{Bom, Tree, item_text};
+use crate::{DocError, Document, Model, Result, ids};
+
+/// The most balloons a drawing may have.
+pub const MAX_BALLOONS: usize = 10_000;
+
+/// One balloon of a drawing.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct Balloon {
+    #[serde(with = "crate::ids")]
+    pub id: u64,
+    /// The view it points into and moves with.
+    #[serde(with = "crate::ids")]
+    pub view: u64,
+    /// The edge its arrow points at. Its occurrence path is the part the balloon numbers.
+    pub edge: ModelEdge,
+    /// The balloon's centre, in millimetres of paper from its view's centre.
+    pub at: [f64; 2],
+    /// The parts list it names, when it names one.
+    #[serde(default, with = "crate::ids::option", skip_serializing_if = "Option::is_none")]
+    pub parts_list: Option<u64>,
+}
+
+impl Balloon {
+    /// The part it numbers: the occurrences its edge's body is placed through, from the top.
+    pub fn occurrence(&self) -> &[u64] {
+        &self.edge.path
+    }
+}
+
+impl Record for Balloon {
+    fn id(&self) -> u64 {
+        self.id
+    }
+}
+
+impl Drawing {
+    /// The parts list balloon `b` reads, by its id: the one it names, else its sheet's only one, else
+    /// the drawing's only one. With none to go by, the lists it could name, by id.
+    pub fn parts_list_for(&self, b: &Balloon) -> std::result::Result<(u64, PartsList), Vec<u64>> {
+        let list = |t: &SheetTable| match t.kind {
+            Kind::PartsList(list) => Some((t.id, list)),
+            Kind::Revision => None,
+        };
+        let lists: Vec<(u64, u64, PartsList)> = self.tables.iter().filter_map(|t| list(t).map(|(id, l)| (id, t.sheet, l))).collect();
+        if let Some(named) = lists.iter().find(|(id, ..)| Some(*id) == b.parts_list) {
+            return Ok((named.0, named.2));
+        }
+        let sheet = self.view(b.view).map(|v| v.sheet);
+        let mut on_sheet = lists.iter().filter(|(_, on, _)| Some(*on) == sheet);
+        if let (Some(only), None) = (on_sheet.next(), on_sheet.next()) {
+            return Ok((only.0, only.2));
+        }
+        match lists.as_slice() {
+            [only] => Ok((only.0, only.2)),
+            _ => Err(lists.iter().map(|(id, ..)| *id).collect()),
+        }
+    }
+
+    /// The balloons that read each parts list ([`Self::parts_list_for`]), by the list's id: each
+    /// balloon's list worked out once. A balloon with no list to go by reads none.
+    pub fn balloons_by_list(&self) -> HashMap<u64, Vec<&Balloon>> {
+        let mut by_list: HashMap<u64, Vec<&Balloon>> = HashMap::new();
+        for b in &self.balloons {
+            if let Ok((list, _)) = self.parts_list_for(b) {
+                by_list.entry(list).or_default().push(b);
+            }
+        }
+        by_list
+    }
+
+    /// The balloons' rules (the module's notes). The views and the tables are checked first, so they
+    /// are in id order here.
+    pub(super) fn check_balloons(&self) -> Result<()> {
+        self.balloons.check(MAX_BALLOONS, "balloon", |b| self.check_balloon(b))
+    }
+
+    fn check_balloon(&self, b: &Balloon) -> Result<()> {
+        require(self.view(b.view).is_some(), || format!("it is on view {}, which the drawing doesn't have", ids::encode(b.view)))?;
+        if let Some(list) = b.parts_list {
+            let named = || format!("it names table {}, which isn't one of the drawing's parts lists", ids::encode(list));
+            require(self.tables.by_id(list).is_some_and(|t| matches!(t.kind, Kind::PartsList(_))), named)?;
+        }
+        check_edge(&b.edge)?;
+        require(!b.edge.path.is_empty(), || "it points at a placed part: its edge's body is placed through an occurrence".into())?;
+        let [x, y] = b.at;
+        require(is_paper_coordinate(x) && is_paper_coordinate(y), || format!("its place is at most {MAX_SIDE_MM} mm on paper"))
+    }
+}
+
+/// How many of `balloons`, those that read one parts list ([`Drawing::balloons_by_list`]), point at
+/// each of its rows, by item ("1.2"): every row of `listed` (that list, made from `tree` with its
+/// members) in its order, 0 included. A balloon whose row is lost counts for none.
+pub fn balloons_by_row(balloons: &[&Balloon], listed: &Bom, tree: &Tree) -> Vec<(String, usize)> {
+    let mut counts: HashMap<String, usize> = HashMap::new();
+    for b in balloons {
+        if let Ok(item) = listed.item_of(tree, b.occurrence()) {
+            *counts.entry(item).or_default() += 1;
+        }
+    }
+    listed
+        .rows_deep()
+        .iter()
+        .map(|(item, _)| {
+            let item = item_text(item);
+            let n = counts.get(&item).copied().unwrap_or(0);
+            (item, n)
+        })
+        .collect()
+}
+
+/// A balloon as the model has it now ([`Document::resolve_balloons`]): never saved.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Resolved {
+    pub status: Status,
+    /// Where its arrow ends, the middle of its edge, in the design's frame: when the edge was found.
+    pub point: Option<Vec3>,
+    /// Its edge was found by exact history, as one edge.
+    pub exact: bool,
+}
+
+impl Document {
+    /// The balloons `wanted` of `drawing` (one of this design's drawings) as `model` (this
+    /// design's) has them now: each one's edge found again by name, and the middle of it. A body is
+    /// looked up and its edge names worked out once for the call, however many balloons name it.
+    /// `Err` only for an id the drawing doesn't have.
+    pub fn resolve_balloons(&self, model: &Model, drawing: &Drawing, wanted: &[u64]) -> Result<Vec<Resolved>> {
+        let mut lookup = Lookup::new(self, model);
+        wanted
+            .iter()
+            .map(|id| {
+                let b = drawing.balloons.by_id(*id).ok_or_else(|| DocError::Unknown(format!("balloon {}", ids::encode(*id))))?;
+                let (status, point, exact) = lookup.middle(&b.edge);
+                Ok(Resolved { status, point, exact })
+            })
+            .collect()
+    }
+}
+
+#[cfg(test)]
+#[path = "balloon_tests.rs"]
+mod tests;

crates/doc/src/drawing/balloon_tests.rs

@@ -0,0 +1,264 @@
+use std::collections::BTreeSet;
+use std::sync::Arc;
+
+use serde_json::{Value, json};
+use solidcraft_geom::drawing_sheet::{self, Orientation, PaperSize};
+use solidcraft_geom::drawing_view::NamedView;
+
+use super::*;
+use crate::drawing::table::{Kind, SheetTable};
+use crate::drawing::view::{View, ViewKind, ViewPlace};
+use crate::drawing::{OnSheet, Sheet, Source};
+use crate::drawing_view::{ViewDirection, ViewOverrides};
+use crate::format::DRAWING;
+use crate::ids::IdSource;
+
+const SEED: u64 = 3874;
+
+fn edge(name: &str, path: Vec<u64>) -> ModelEdge {
+    ModelEdge { body: "Bolt".into(), origin_feature: 4, name: name.into(), path }
+}
+
+/// A drawing of one design on one A3 sheet, its front view at (150, 150), and on the view two
+/// balloons: one on a bolt placed straight in the design (occurrence 3), one on a bolt inside a
+/// sub-assembly (occurrence 7 in 3). Their ids, in the order they were added.
+fn ballooned() -> (Drawing, [u64; 2]) {
+    let mut id_source = IdSource::seeded(SEED);
+    let a3 = drawing_sheet::Sheet::standard(PaperSize::A3, Orientation::Landscape);
+    let mut d = Drawing::new("Bolted", "en", "Sheet 1", a3, None, &BTreeSet::new(), &mut id_source).unwrap();
+    let source = d.allocate_id(&mut id_source).unwrap();
+    d.sources.push(Source { id: source });
+    let (view, sheet) = (d.allocate_id(&mut id_source).unwrap(), d.sheets[0].id);
+    let kind = ViewKind::Base { source, view: ViewDirection::Named(NamedView::Front) };
+    d.add_views([Arc::new(View {
+        id: view,
+        sheet,
+        kind,
+        place: ViewPlace::At([150.0, 150.0]),
+        settings: ViewOverrides { scale: Some("1:2".parse().unwrap()), ..ViewOverrides::default() },
+        reference_shown_percent: 0.0,
+    })]);
+    let mut added = [0; 2];
+    for ((path, at), id) in [(vec![3], [40.0, 25.0]), (vec![3, 7], [-35.5, 60.0])].into_iter().zip(&mut added) {
+        *id = d.allocate_id(&mut id_source).unwrap();
+        d.balloons.add([Arc::new(Balloon { id: *id, view, edge: edge("F1:side|F2:head", path), at, parts_list: None })]);
+    }
+    d.validate().unwrap();
+    (d, added)
+}
+
+fn file(d: &Drawing) -> Value {
+    serde_json::from_str(&d.to_json().unwrap()).unwrap()
+}
+
+/// Balloon `id` in a drawing's file.
+fn balloon<'a>(v: &'a mut Value, id: &str) -> &'a mut Value {
+    v["balloons"].as_array_mut().unwrap().iter_mut().find(|x| x["id"] == id).unwrap()
+}
+
+/// Why `d`'s file, changed by `edit`, is refused, or "read".
+fn refused(d: &Drawing, edit: impl FnOnce(&mut Value)) -> String {
+    let mut v = file(d);
+    edit(&mut v);
+    Drawing::from_json(&v.to_string()).map_or_else(|e| e.to_string(), |_| "read".into())
+}
+
+/// A balloon saves its view, its edge by name with the part's occurrence path, and its place, and
+/// nothing worked out. Balloons save by id and read back as saved, the same bytes again; a file
+/// that lists them in another order reads by id. An older drawing reads with none, and a drawing
+/// with none writes none.
+#[test]
+fn balloons_save_what_they_point_at_and_read_back_as_saved() {
+    let (d, added) = ballooned();
+    let [placed, nested] = added.map(ids::encode);
+    let view = ids::encode(d.views[0].id);
+    let mut v = file(&d);
+    assert_eq!(
+        *balloon(&mut v, &nested),
+        json!({
+            "id": nested, "view": view,
+            "edge": {"body": "Bolt", "origin_feature": 4, "name": "F1:side|F2:head", "path": [3, 7]},
+            "at": [-35.5, 60.0]
+        })
+    );
+    assert_eq!(balloon(&mut v, &placed)["edge"]["path"], json!([3]));
+    assert_eq!(d.balloons.by_id(added[1]).unwrap().occurrence(), [3, 7], "the part it numbers is its edge's path");
+    let listed: Vec<u64> = v["balloons"].as_array().unwrap().iter().map(|x| ids::decode(x["id"].as_str().unwrap()).unwrap()).collect();
+    let mut by_id = added.to_vec();
+    by_id.sort_unstable();
+    assert_eq!(listed, by_id);
+    let reopened = Drawing::from_json(&d.to_json().unwrap()).unwrap();
+    assert_eq!(reopened, d);
+    assert_eq!(reopened.to_json().unwrap(), d.to_json().unwrap());
+    let mut other_order = v.clone();
+    other_order["balloons"].as_array_mut().unwrap().reverse();
+    assert_eq!(Drawing::from_json(&other_order.to_string()).unwrap(), d);
+    let mut unsorted = d.clone();
+    unsorted.balloons.reverse();
+    assert_eq!(unsorted.validate().unwrap_err().to_string(), "a drawing lists its balloons by id");
+    let mut none = d.clone();
+    none.balloons.clear();
+    assert_eq!(file(&none).get("balloons"), None, "no balloons, none written");
+    let older = json!({
+        "format": DRAWING.format_string(1), "id": "0000000000002", "name": "Old", "sources": [], "language": "en",
+        "sheets": [{"id": "0000000000001", "name": "S", "sheet": {"size": {"standard": "a4"}}}]
+    });
+    assert!(Drawing::from_json(&older.to_string()).unwrap().balloons.is_empty());
+}
+
+/// What reading refuses, each rule by name, on both sides of every cap: the view a balloon is on,
+/// its edge's names, feature and path (a placed part's: 1 to 64 occurrences, none of them 0), its
+/// place on paper, its id, how many there are, and fields it doesn't know.
+#[test]
+fn the_balloons_rules_are_kept_on_reading() {
+    let (d, added) = ballooned();
+    let [placed, nested] = added.map(ids::encode);
+    let rule = |id: &str, rule: &str| format!("damaged drawing: balloon {id}: {rule}");
+    let nothing = ids::encode(99);
+    let on = format!("it is on view {nothing}, which the drawing doesn't have");
+    assert_eq!(refused(&d, |v| balloon(v, &placed)["view"] = json!(nothing)), rule(&placed, &on));
+    // The edge keeps a dimension's reference rules.
+    let names = "a name in a reference is 1 to 512 bytes, without control characters";
+    let body = |name: &str| refused(&d, |v| balloon(v, &nested)["edge"]["body"] = json!(name));
+    let edge_name = |name: &str| refused(&d, |v| balloon(v, &nested)["edge"]["name"] = json!(name));
+    for fits in ["x".repeat(512), "é".repeat(256)] {
+        assert_eq!([body(&fits), edge_name(&fits)], ["read", "read"], "{} bytes", fits.len());
+    }
+    for broken in ["x".repeat(513), String::new(), "two\nlines".into()] {
+        assert_eq!([body(&broken), edge_name(&broken)], [rule(&nested, names), rule(&nested, names)], "{} bytes", broken.len());
+    }
+    let feature = rule(&placed, "a reference names the feature that made its body");
+    assert_eq!(refused(&d, |v| balloon(v, &placed)["edge"]["origin_feature"] = json!(0)), feature);
+    // A placed part's path: 1 to 64 occurrences, none of them 0. A design's own body is no part.
+    let path = |p: Value| refused(&d, |v| balloon(v, &nested)["edge"]["path"] = p);
+    let deep = rule(&nested, "an occurrence path is at most 64 occurrences, none of them 0");
+    let own = rule(&nested, "it points at a placed part: its edge's body is placed through an occurrence");
+    assert_eq!(
+        [path(json!([3])), path(json!(vec![3; 64])), path(json!(vec![3; 65])), path(json!([3, 0])), path(json!([]))],
+        ["read".to_string(), "read".into(), deep.clone(), deep, own.clone()]
+    );
+    let no_path = refused(&d, |v| {
+        balloon(v, &nested)["edge"].as_object_mut().unwrap().remove("path");
+    });
+    assert_eq!(no_path, own, "no path");
+    // Its place is on paper.
+    let paper = rule(&placed, "its place is at most 5000 mm on paper");
+    let at = |at: [f64; 2]| refused(&d, |v| balloon(v, &placed)["at"] = json!(at));
+    assert_eq!([at([5000.0, -5000.0]), at([5000.001, 0.0]), at([0.0, -5000.001])], ["read".to_string(), paper.clone(), paper]);
+    assert!(refused(&d, |v| balloon(v, &placed)["at"] = json!([1.0])).starts_with("damaged drawing: "), "two numbers");
+    // Its id is the drawing's: never another object's.
+    let view_id = ids::encode(d.views[0].id);
+    assert_eq!(refused(&d, |v| balloon(v, &placed)["id"] = json!(view_id)), format!("damaged drawing: two objects have the id {view_id}"));
+    // Fields it doesn't know, at every level.
+    let unknown: [fn(&mut Value, &str); 3] = [
+        |v, id| balloon(v, id)["item"] = json!(3),
+        |v, id| balloon(v, id)["edge"]["point"] = json!([0.0, 0.0, 0.0]),
+        |v, id| balloon(v, id)["shape"] = json!("circle"),
+    ];
+    for (i, edit) in unknown.into_iter().enumerate() {
+        assert!(refused(&d, |v| edit(v, &placed)).starts_with("damaged drawing: "), "{i}");
+    }
+    // At most MAX_BALLOONS balloons.
+    let many = |n: usize| {
+        let mut v = file(&d);
+        let one = balloon(&mut v, &placed).clone();
+        let copies = (1..=n as u64).map(|i| {
+            let mut copy = one.clone();
+            copy["id"] = json!(ids::encode(i));
+            copy
+        });
+        v["balloons"] = Value::Array(copies.collect());
+        Drawing::from_json(&v.to_string()).map(|d| d.balloons.len()).map_err(|e| e.to_string())
+    };
+    assert_eq!(many(MAX_BALLOONS), Ok(MAX_BALLOONS));
+    assert_eq!(many(MAX_BALLOONS + 1), Err(format!("damaged drawing: a drawing has at most {MAX_BALLOONS} balloons")));
+}
+
+/// A sheet's balloons are its views' and go with it; a new id never takes a balloon's.
+#[test]
+fn a_sheets_balloons_go_with_it() {
+    let (mut d, added) = ballooned();
+    let sheet = d.sheets[0].id;
+    let on = d.on_sheet(sheet);
+    let mut by_id = added.to_vec();
+    by_id.sort_unstable();
+    assert_eq!(on.balloons, by_id);
+    let mut id_source = IdSource::seeded(SEED);
+    for _ in 0..64 {
+        let id = d.allocate_id(&mut id_source).unwrap();
+        assert!(!added.contains(&id), "a new id never takes a balloon's");
+    }
+    let second = d.allocate_id(&mut id_source).unwrap();
+    d.sheets.push(Arc::new(crate::drawing::Sheet { id: second, name: "Sheet 2".into(), ..(*d.sheets[0]).clone() }));
+    assert_eq!(d.remove_sheet(sheet), on);
+    d.validate().unwrap();
+    assert!(d.balloons.is_empty() && d.views.is_empty());
+}
+
+/// A parts list on `d`'s sheet `sheet`, with a fresh id.
+fn add_list(d: &mut Drawing, sheet: u64, id: u64) {
+    use crate::drawing::SheetComponent;
+    use crate::drawing::table::{MassFormat, PartsList};
+    let of = SheetComponent { source: d.sources[0].id, component: 0 };
+    let list =
+        PartsList { of, view: Default::default(), group: Default::default(), fold: false, purchased_contents: false, mass: MassFormat::default() };
+    let kind = Kind::PartsList(list);
+    d.tables.add([Arc::new(SheetTable { id, sheet, table: kind.default_table(), place: kind.default_place(), kind })]);
+}
+
+/// With no link a balloon reads its sheet's only list, else the drawing's only one, else none, with
+/// the choices listed; a revision table is no choice. Its link wins. Saved only when it names one.
+#[test]
+fn a_balloon_reads_the_list_it_names_else_the_only_one() {
+    let (mut d, [id, _]) = ballooned();
+    let sheet = d.sheets[0].id;
+    let read = |d: &Drawing| d.parts_list_for(d.balloons.by_id(id).unwrap()).map(|(list, _)| list);
+    assert_eq!(read(&d), Err(vec![]));
+    let saved: Value = serde_json::from_str(&d.to_json().unwrap()).unwrap();
+    assert_eq!(saved["balloons"][0].get("parts_list"), None);
+
+    let other = 1 << 40;
+    let a4 = drawing_sheet::Sheet::standard(PaperSize::A4, Orientation::Landscape);
+    d.sheets.push(Arc::new(Sheet { id: other, name: "Other".into(), sheet: a4, ..(*d.sheets[0]).clone() }));
+    add_list(&mut d, other, 1 << 41);
+    assert_eq!(read(&d), Ok(1 << 41), "the drawing's only one");
+    add_list(&mut d, sheet, 1 << 42);
+    assert_eq!(read(&d), Ok(1 << 42), "the sheet's only one comes first");
+    add_list(&mut d, sheet, 1 << 43);
+    assert_eq!(read(&d), Err(vec![1 << 41, 1 << 42, 1 << 43]), "the choices");
+    assert!(d.balloons_by_list().is_empty(), "with none to go by, a balloon reads no list");
+    let kind = Kind::Revision;
+    d.tables.add([Arc::new(SheetTable { id: 1 << 44, sheet, table: kind.default_table(), place: kind.default_place(), kind })]);
+    assert_eq!(read(&d).unwrap_err().len(), 3, "a revision table is no choice");
+
+    let at = d.balloons.index_of(id).unwrap();
+    Arc::make_mut(&mut d.balloons[at]).parts_list = Some(1 << 41);
+    assert_eq!(read(&d), Ok(1 << 41), "its link wins");
+    let by_list = d.balloons_by_list();
+    assert_eq!((by_list.len(), by_list[&(1 << 41)].iter().map(|b| b.id).collect::<Vec<_>>()), (1, vec![id]), "the other reads none");
+    d.validate().unwrap();
+    assert_eq!(Drawing::from_json(&d.to_json().unwrap()).unwrap(), d);
+
+    // The list goes, by its own delete or its sheet's: the balloon stays and reads what it can.
+    d.remove_objects(&OnSheet { tables: vec![1 << 41], ..Default::default() });
+    assert_eq!(d.balloons.by_id(id).unwrap().parts_list, None);
+    d.validate().unwrap();
+    assert_eq!(read(&d).unwrap_err(), vec![1 << 42, 1 << 43]);
+}
+
+/// A link names one of the drawing's parts lists.
+#[test]
+fn a_balloons_link_is_to_a_parts_list() {
+    let (mut d, [id, _]) = ballooned();
+    let sheet = d.sheets[0].id;
+    let kind = Kind::Revision;
+    d.tables.add([Arc::new(SheetTable { id: 1 << 44, sheet, table: kind.default_table(), place: kind.default_place(), kind })]);
+    let at = d.balloons.index_of(id).unwrap();
+    for bad in [1 << 44, 99] {
+        Arc::make_mut(&mut d.balloons[at]).parts_list = Some(bad);
+        assert!(d.validate().unwrap_err().to_string().contains("parts lists"), "{bad}");
+    }
+    let mut v: Value = serde_json::from_str(&Drawing { balloons: Default::default(), ..d.clone() }.to_json().unwrap()).unwrap();
+    v["balloons"] = json!([{"id": "x", "view": "x", "edge": {}, "at": [0.0, 0.0], "parts_list": 7}]);
+    assert!(Drawing::from_value(v).is_err(), "not an id");
+}

crates/doc/src/drawing/by_id.rs

@@ -0,0 +1,90 @@
+//! A drawing's list of one kind of record: each behind its own `Arc`, so an undo step shares what it
+//! didn't change, and by id, whatever order they came in. It holds what every such list does, so a
+//! kind's own file holds only its own rules.
+
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use serde::{Deserialize, Serialize};
+
+use super::require;
+use crate::{DocError, Result, ids};
+
+/// A record a drawing lists by its id.
+pub trait Record {
+    fn id(&self) -> u64;
+}
+
+/// The records of one kind, by id. It reads as the `Vec` it is, and a file holds them as one.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(transparent)]
+pub struct ById<T>(Vec<Arc<T>>);
+
+impl<T> Default for ById<T> {
+    fn default() -> Self {
+        ById(Vec::new())
+    }
+}
+
+impl<T> Deref for ById<T> {
+    type Target = Vec<Arc<T>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<T> DerefMut for ById<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl<'a, T> IntoIterator for &'a ById<T> {
+    type Item = &'a Arc<T>;
+    type IntoIter = std::slice::Iter<'a, Arc<T>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.0.iter()
+    }
+}
+
+impl<T> ById<T> {
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
+}
+
+impl<T: Record> ById<T> {
+    /// Adds `more`, each where its id puts it.
+    pub fn add(&mut self, more: impl IntoIterator<Item = Arc<T>>) {
+        self.0.extend(more);
+        self.put_in_order();
+    }
+
+    /// Puts what a file listed in another order where each id puts it.
+    pub(super) fn put_in_order(&mut self) {
+        self.0.sort_by_key(|record| record.id());
+    }
+
+    /// Where record `id` is in the list, found by halves.
+    pub fn index_of(&self, id: u64) -> Option<usize> {
+        self.0.binary_search_by_key(&id, |record| record.id()).ok()
+    }
+
+    /// Record `id`.
+    pub fn by_id(&self, id: u64) -> Option<&T> {
+        self.index_of(id).and_then(|at| self.0.get(at)).map(|record| &**record)
+    }
+
+    /// The list's rules, each named by `word`: at most `most` records, by id, each keeping `rule`.
+    pub(super) fn check(&self, most: usize, word: &str, rule: impl Fn(&T) -> Result<()>) -> Result<()> {
+        require(self.0.len() <= most, || format!("a drawing has at most {most} {word}s"))?;
+        require(self.0.is_sorted_by_key(|record| record.id()), || format!("a drawing lists its {word}s by id"))?;
+        self.0.iter().try_for_each(|record| rule(record).map_err(|e| DocError::Invalid(format!("{word} {}: {e}", ids::encode(record.id())))))
+    }
+}
+
+#[cfg(test)]
+#[path = "by_id_tests.rs"]
+mod tests;

crates/doc/src/drawing/by_id_tests.rs

@@ -0,0 +1,50 @@
+use serde_json::json;
+
+use super::*;
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+struct Thing(u64);
+
+impl Record for Thing {
+    fn id(&self) -> u64 {
+        self.0
+    }
+}
+
+fn things(ids: &[u64]) -> ById<Thing> {
+    let mut list = ById::default();
+    list.add(ids.iter().map(|id| Arc::new(Thing(*id))));
+    list
+}
+
+#[test]
+fn records_go_where_their_ids_put_them_and_are_found_there() {
+    let mut list = things(&[30, 10]);
+    list.add([Arc::new(Thing(20))]);
+    assert_eq!(list.iter().map(|t| t.0).collect::<Vec<_>>(), [10, 20, 30]);
+    assert_eq!((list.index_of(20), list.by_id(30).map(|t| t.0)), (Some(1), Some(30)));
+    assert_eq!((list.index_of(25), list.by_id(25)), (None, None));
+    assert!(ById::<Thing>::default().is_empty() && !list.is_empty());
+}
+
+#[test]
+fn a_file_holds_the_plain_list() {
+    let list = things(&[1, 2]);
+    assert_eq!(serde_json::to_value(&list).unwrap(), json!([1, 2]));
+    assert_eq!(serde_json::from_value::<ById<Thing>>(json!([1, 2])).unwrap(), list);
+}
+
+#[test]
+fn the_rules_name_the_kind_and_the_record() {
+    let fine = |_: &Thing| Ok(());
+    things(&[1, 2]).check(2, "thing", fine).unwrap();
+    assert!(things(&[1, 2, 3]).check(2, "thing", fine).is_err_and(|e| e.to_string().contains("at most 2 things")));
+    let mut out_of_order = things(&[1, 2]);
+    out_of_order.reverse();
+    assert!(out_of_order.check(2, "thing", fine).is_err_and(|e| e.to_string().contains("lists its things by id")));
+    out_of_order.put_in_order();
+    out_of_order.check(2, "thing", fine).unwrap();
+    let odd = |t: &Thing| require(t.0.is_multiple_of(2), || "it is odd".into());
+    let e = things(&[2, 3]).check(2, "thing", odd).unwrap_err().to_string();
+    assert!(e.contains(&format!("thing {}: it is odd", ids::encode(3))), "{e}");
+}

crates/doc/src/drawing/dimension_tests.rs

@@ -0,0 +1,581 @@
+use std::collections::{BTreeMap, BTreeSet};
+
+use serde_json::{Value, json};
+use solidcore_record::Vec2;
+use solidcraft_geom::drawing_sheet::{self, Orientation, PaperSize};
+use solidcraft_geom::drawing_view::NamedView;
+
+use super::*;
+use crate::drawing::Source;
+use crate::drawing::view::{View, ViewKind, ViewPlace};
+use crate::drawing_view::{ViewDirection, ViewOverrides};
+use crate::format::DRAWING;
+use crate::ids::IdSource;
+
+const SEED: u64 = 4896;
+/// The body every reference here is on, and the feature that made it.
+const BODY: &str = "Box";
+const FEATURE: u64 = 7;
+
+fn corner(edges: &[&str]) -> ModelPoint {
+    ModelPoint { body: BODY.into(), origin_feature: FEATURE, edges: edges.iter().map(|e| e.to_string()).collect(), centre: false, path: Vec::new() }
+}
+
+fn edge(name: &str) -> ModelEdge {
+    ModelEdge { body: BODY.into(), origin_feature: FEATURE, name: name.into(), path: Vec::new() }
+}
+
+/// A drawing of one design on one A3 sheet, its front view at 1:2 at (150, 150), and on the view a
+/// linear dimension between two corners, an edge's length and an angle between two edges: their
+/// ids, in the order they were added.
+fn measured() -> (Drawing, [u64; 3]) {
+    let mut id_source = IdSource::seeded(SEED);
+    let a3 = drawing_sheet::Sheet::standard(PaperSize::A3, Orientation::Landscape);
+    let mut d = Drawing::new("Box", "en", "Sheet 1", a3, None, &BTreeSet::new(), &mut id_source).unwrap();
+    let source = d.allocate_id(&mut id_source).unwrap();
+    d.sources.push(Source { id: source });
+    let (view, sheet) = (d.allocate_id(&mut id_source).unwrap(), d.sheets[0].id);
+    let kind = ViewKind::Base { source, view: ViewDirection::Named(NamedView::Front) };
+    let settings = ViewOverrides { scale: Some("1:2".parse().unwrap()), ..ViewOverrides::default() };
+    d.add_views([Arc::new(View { id: view, sheet, kind, place: ViewPlace::At([150.0, 150.0]), settings, reference_shown_percent: 0.0 })]);
+    let kinds = [
+        DimensionKind::Linear {
+            a: corner(&["F1:front|F1:bottom", "F1:front|F1:left"]),
+            b: corner(&["F1:front|F1:bottom", "F1:front|F1:right"]),
+            direction: LinearDirection::Horizontal,
+            reading: Reading::Projected,
+        },
+        DimensionKind::Length { edge: edge("F1:front|F1:top"), direction: LinearDirection::Aligned, reading: Reading::True },
+        DimensionKind::Angle { a: edge("F1:front|F1:top"), b: edge("F2:chamfer|F1:front"), reading: Reading::Projected, other_side: true },
+    ];
+    let texts = [TextPlace::Centred, TextPlace::At([0.0, -20.0]), TextPlace::At([12.5, 30.0])];
+    let mut added = [0; 3];
+    for ((kind, text), id) in kinds.into_iter().zip(texts).zip(&mut added) {
+        *id = d.allocate_id(&mut id_source).unwrap();
+        d.add_dimensions([Arc::new(Dimension { id: *id, view, kind, offset_mm: -10.0, text, decimals: 2, override_text: None, last_good: None })]);
+    }
+    d.validate().unwrap();
+    (d, added)
+}
+
+fn file(d: &Drawing) -> Value {
+    serde_json::from_str(&d.to_json().unwrap()).unwrap()
+}
+
+/// Dimension `id` in a drawing's file.
+fn dim<'a>(v: &'a mut Value, id: &str) -> &'a mut Value {
+    v["dimensions"].as_array_mut().unwrap().iter_mut().find(|x| x["id"] == id).unwrap()
+}
+
+/// Why `d`'s file, changed by `edit`, is refused, or "read".
+fn refused(d: &Drawing, edit: impl FnOnce(&mut Value)) -> String {
+    let mut v = file(d);
+    edit(&mut v);
+    Drawing::from_json(&v.to_string()).map_or_else(|e| e.to_string(), |_| "read".into())
+}
+
+/// A dimension saves what it measures by name, its offset, its text's place and its decimals, and
+/// nothing it leaves out. The dimensions save by id, whatever order they were added in, and read
+/// back as saved, the same bytes again; a file that lists them in another order reads by id. An
+/// older drawing reads with none, and a drawing with none writes none.
+#[test]
+fn dimensions_save_what_they_measure_and_read_back_as_saved() {
+    let (d, added) = measured();
+    let [linear_id, length_id, angle_id] = added.map(ids::encode);
+    let view = ids::encode(d.views[0].id);
+    let mut v = file(&d);
+    let box_corner = |edges: [&str; 2]| json!({"body": "Box", "origin_feature": 7, "edges": edges});
+    assert_eq!(
+        *dim(&mut v, &linear_id),
+        json!({
+            "id": linear_id, "view": view,
+            "kind": {"linear": {
+                "a": box_corner(["F1:front|F1:bottom", "F1:front|F1:left"]),
+                "b": box_corner(["F1:front|F1:bottom", "F1:front|F1:right"]),
+                "direction": "horizontal", "reading": "projected"
+            }},
+            "offset_mm": -10.0, "text": "centred", "decimals": 2
+        })
+    );
+    let length = dim(&mut v, &length_id).clone();
+    let top_edge = json!({"body": "Box", "origin_feature": 7, "name": "F1:front|F1:top"});
+    assert_eq!(length["kind"], json!({"length": {"edge": top_edge, "direction": "aligned", "reading": "true"}}));
+    assert_eq!(length["text"], json!({"at": [0.0, -20.0]}));
+    assert_eq!(dim(&mut v, &angle_id)["kind"]["angle"]["other_side"], json!(true));
+    let mut one_side = v.clone();
+    dim(&mut one_side, &angle_id)["kind"]["angle"].as_object_mut().unwrap().remove("other_side");
+    let one_side = Drawing::from_json(&one_side.to_string()).unwrap();
+    assert_eq!(dim(&mut file(&one_side), &angle_id)["kind"]["angle"].get("other_side"), None, "the usual side, not written");
+    let listed: Vec<u64> = v["dimensions"].as_array().unwrap().iter().map(|x| ids::decode(x["id"].as_str().unwrap()).unwrap()).collect();
+    let mut by_id = added.to_vec();
+    by_id.sort_unstable();
+    assert_eq!(listed, by_id);
+    let reopened = Drawing::from_json(&d.to_json().unwrap()).unwrap();
+    assert_eq!(reopened, d);
+    assert_eq!(reopened.to_json().unwrap(), d.to_json().unwrap());
+    let mut other_order = v.clone();
+    other_order["dimensions"].as_array_mut().unwrap().reverse();
+    assert_eq!(Drawing::from_json(&other_order.to_string()).unwrap(), d);
+    let mut unsorted = d.clone();
+    unsorted.dimensions.reverse();
+    assert_eq!(unsorted.validate().unwrap_err().to_string(), "a drawing lists its dimensions by id");
+    let mut none = d.clone();
+    none.dimensions.clear();
+    assert_eq!(file(&none).get("dimensions"), None, "no dimensions, none written");
+    let older = json!({
+        "format": DRAWING.format_string(1), "id": "0000000000002", "name": "Old", "sources": [], "language": "en",
+        "sheets": [{"id": "0000000000001", "name": "S", "sheet": {"size": {"standard": "a4"}}}]
+    });
+    assert!(Drawing::from_json(&older.to_string()).unwrap().dimensions.is_empty());
+}
+
+/// What reading refuses, each rule by name, on both sides of every cap: the view a dimension is
+/// on, the names, the feature and the path of its references, a corner's edges, its direction and
+/// reading, its offset and text place, its decimals and its text, its id, how many there are, and
+/// fields it doesn't know.
+#[test]
+fn the_dimensions_rules_are_kept_on_reading() {
+    let (d, added) = measured();
+    let [linear_id, length_id, angle_id] = added.map(ids::encode);
+    let rule = |id: &str, rule: &str| format!("damaged drawing: dimension {id}: {rule}");
+    let nothing = ids::encode(99);
+    let on = format!("it is on view {nothing}, which the drawing doesn't have");
+    assert_eq!(refused(&d, |v| dim(v, &linear_id)["view"] = json!(nothing)), rule(&linear_id, &on));
+    // Names: of the body, an edge and a corner's edges, 1 to 512 bytes without control characters.
+    let names = "a name in a reference is 1 to 512 bytes, without control characters";
+    let body = |name: &str| refused(&d, |v| dim(v, &length_id)["kind"]["length"]["edge"]["body"] = json!(name));
+    let edge_name = |name: &str| refused(&d, |v| dim(v, &angle_id)["kind"]["angle"]["b"]["name"] = json!(name));
+    let corner_edge = |name: &str| refused(&d, |v| dim(v, &linear_id)["kind"]["linear"]["a"]["edges"][1] = json!(name));
+    for fits in ["x".repeat(512), "é".repeat(256), "F1:front|F1:top".into()] {
+        assert_eq!([body(&fits), edge_name(&fits), corner_edge(&fits)], ["read", "read", "read"], "{} bytes", fits.len());
+    }
+    for broken in ["x".repeat(513), "é".repeat(256) + "a", "x".repeat(1_000_000), String::new(), "two\nlines".into(), "nul\0".into()] {
+        let expected = [rule(&length_id, names), rule(&angle_id, names), rule(&linear_id, names)];
+        assert_eq!([body(&broken), edge_name(&broken), corner_edge(&broken)], expected, "{} bytes", broken.len());
+    }
+    // A corner is where 2 to 16 named edges meet.
+    let edges = |n: usize| {
+        refused(&d, |v| dim(v, &linear_id)["kind"]["linear"]["b"]["edges"] = json!((0..n).map(|i| format!("F1:e{i}")).collect::<Vec<_>>()))
+    };
+    let meet = rule(&linear_id, "a corner is where 2 to 16 named edges meet");
+    assert_eq!([edges(0), edges(1), edges(2), edges(16), edges(17)], [meet.clone(), meet.clone(), "read".into(), "read".into(), meet]);
+    // A centre is of one named circle or arc, and saves as `centre`.
+    let centred = |n: usize| {
+        let mut v = file(&d);
+        let b = &mut dim(&mut v, &linear_id)["kind"]["linear"]["b"];
+        b["centre"] = json!(true);
+        b["edges"] = json!((0..n).map(|i| format!("F3:e{i}")).collect::<Vec<_>>());
+        let read = Drawing::from_json(&v.to_string()).map_err(|e| e.to_string())?;
+        Ok::<_, String>(dim(&mut file(&read), &linear_id)["kind"]["linear"]["b"].clone())
+    };
+    let one = Err(rule(&linear_id, "a centre is of one named circle or arc"));
+    assert_eq!([centred(0), centred(2)], [one.clone(), one]);
+    assert_eq!(centred(1), Ok(json!({"body": "Box", "origin_feature": 7, "edges": ["F3:e0"], "centre": true})));
+    // The feature that made the body, and the occurrence path.
+    let feature = rule(&length_id, "a reference names the feature that made its body");
+    assert_eq!(refused(&d, |v| dim(v, &length_id)["kind"]["length"]["edge"]["origin_feature"] = json!(0)), feature);
+    let path = |p: Vec<u64>| refused(&d, |v| dim(v, &angle_id)["kind"]["angle"]["a"]["path"] = json!(p));
+    let deep = rule(&angle_id, "an occurrence path is at most 64 occurrences, none of them 0");
+    assert_eq!([path(vec![3; 64]), path(vec![3; 65]), path(vec![3, 0]), path(vec![])], ["read".into(), deep.clone(), deep, "read".to_string()]);
+    // A direction to measure along that isn't zero, and a true length measured aligned.
+    let along = |a: Value| refused(&d, |v| dim(v, &length_id)["kind"]["length"]["direction"] = json!({"along": a}));
+    let zero = rule(&length_id, "the direction to measure along is zero or not finite");
+    assert_eq!(along(json!([0.0, 0.0])), zero);
+    assert!(along(json!([1e308, 1e308])).ends_with("is out of range"), "the file's own number check, before the record's");
+    // A whole number passes the file's check but would save as one past it: the record refuses it.
+    assert_eq!(along(json!([u64::MAX, 0])), rule(&length_id, "the direction to measure along is at most 1000000000 each way"));
+    assert_eq!(along(json!([1_000_000_000, 1])), rule(&length_id, "a true length is measured aligned"), "1e9 each way passes");
+    assert_eq!(along(json!([0.0, 2.0])), rule(&length_id, "a true length is measured aligned"), "along, read true");
+    let projected_along = refused(&d, |v| {
+        dim(v, &length_id)["kind"]["length"]["direction"] = json!({"along": [0.0, 2.0]});
+        dim(v, &length_id)["kind"]["length"]["reading"] = json!("projected");
+    });
+    assert_eq!(projected_along, "read");
+    let true_horizontal = refused(&d, |v| dim(v, &linear_id)["kind"]["linear"]["reading"] = json!("true"));
+    assert_eq!(true_horizontal, rule(&linear_id, "a true length is measured aligned"));
+    // On paper: the offset and the text's place.
+    let paper = rule(&angle_id, "its offset and its text's place are at most 5000 mm on paper");
+    let offset = |mm: f64| refused(&d, |v| dim(v, &angle_id)["offset_mm"] = json!(mm));
+    let text = |at: [f64; 2]| refused(&d, |v| dim(v, &angle_id)["text"] = json!({"at": at}));
+    assert_eq!([offset(5000.0), offset(-5000.0), offset(5000.001), offset(-5000.001)], ["read".into(), "read".into(), paper.clone(), paper.clone()]);
+    assert_eq!([text([5000.0, -5000.0]), text([5000.001, 0.0]), text([0.0, -5000.001])], ["read".into(), paper.clone(), paper]);
+    // Decimals, and the text shown instead of the number.
+    let decimals = |n: u64| refused(&d, |v| dim(v, &angle_id)["decimals"] = json!(n));
+    assert_eq!([decimals(0), decimals(6), decimals(7)], ["read".into(), "read".into(), rule(&angle_id, "it shows at most 6 decimals")]);
+    assert!(decimals(256).starts_with("damaged drawing: "), "past a u8");
+    let instead = |text: &str| refused(&d, |v| dim(v, &linear_id)["override_text"] = json!(text));
+    let text_rule = rule(&linear_id, "the text shown instead of its number is 1 to 1024 bytes");
+    assert_eq!(
+        [instead("≈80"), instead(&"x".repeat(1024)), instead(""), instead(&"x".repeat(1025))],
+        ["read".into(), "read".into(), text_rule.clone(), text_rule]
+    );
+    // Its id is the drawing's: never another object's.
+    let view_id = ids::encode(d.views[0].id);
+    assert_eq!(refused(&d, |v| dim(v, &length_id)["id"] = json!(view_id)), format!("damaged drawing: two objects have the id {view_id}"));
+    // Fields it doesn't know, at every level.
+    let unknown: [fn(&mut Value, &str); 5] = [
+        |v, id| dim(v, id)["label"] = json!("A"),
+        |v, id| dim(v, id)["kind"]["linear"]["tolerance"] = json!(0.1),
+        |v, id| dim(v, id)["kind"]["linear"]["a"]["point"] = json!([0.0, 0.0, 0.0]),
+        |v, id| dim(v, id)["text"] = json!({"at": [1.0, 2.0], "angle": 3.0}),
+        |v, id| dim(v, id)["kind"] = json!({"baseline": {}}),
+    ];
+    for (i, edit) in unknown.into_iter().enumerate() {
+        assert!(refused(&d, |v| edit(v, &linear_id)).starts_with("damaged drawing: "), "{i}");
+    }
+    // At most MAX_DIMENSIONS dimensions.
+    let many = |n: usize| {
+        let mut v = file(&d);
+        let one = dim(&mut v, &linear_id).clone();
+        let copies = (1..=n as u64).map(|i| {
+            let mut copy = one.clone();
+            copy["id"] = json!(ids::encode(i));
+            copy
+        });
+        v["dimensions"] = Value::Array(copies.collect());
+        Drawing::from_json(&v.to_string()).map(|d| d.dimensions.len()).map_err(|e| e.to_string())
+    };
+    assert_eq!(many(MAX_DIMENSIONS), Ok(MAX_DIMENSIONS));
+    assert_eq!(many(MAX_DIMENSIONS + 1), Err(format!("damaged drawing: a drawing has at most {MAX_DIMENSIONS} dimensions")));
+}
+
+/// Two lines at 45° read 45°, and 135° on the other side, whichever way each runs: the angle
+/// between their directions is 45° or 135° by how the kernel runs the edges.
+#[test]
+fn an_angle_between_lines_reads_the_same_whichever_way_they_run() {
+    let (acute, obtuse) = (45f64.to_radians(), 135f64.to_radians());
+    for between in [acute, obtuse] {
+        assert!((between_lines(between, false) - acute).abs() < 1e-12, "{between}");
+        assert!((between_lines(between, true) - obtuse).abs() < 1e-12, "{between}");
+    }
+}
+
+/// A radial dimension saves its edge, and `diameter` only when it is one; its edge keeps an edge's
+/// rules, and it has no reading.
+#[test]
+fn a_radial_dimension_saves_its_edge_and_whether_it_is_a_diameter() {
+    let (mut d, _) = measured();
+    let (view, id) = (d.views[0].id, d.allocate_id(&mut IdSource::seeded(SEED + 1)).unwrap());
+    let radial = |diameter| DimensionKind::Radial { edge: edge("F3:hole|F1:front"), diameter };
+    let kind = radial(true);
+    d.add_dimensions([Arc::new(Dimension {
+        id,
+        view,
+        kind,
+        offset_mm: 5.0,
+        text: TextPlace::Centred,
+        decimals: 1,
+        override_text: None,
+        last_good: None,
+    })]);
+    d.validate().unwrap();
+    let radial_id = ids::encode(id);
+    let mut v = file(&d);
+    let hole = json!({"body": "Box", "origin_feature": 7, "name": "F3:hole|F1:front"});
+    assert_eq!(dim(&mut v, &radial_id)["kind"], json!({"radial": {"edge": hole, "diameter": true}}));
+    assert_eq!(Drawing::from_json(&v.to_string()).unwrap(), d);
+    dim(&mut v, &radial_id)["kind"]["radial"].as_object_mut().unwrap().remove("diameter");
+    let radius = Drawing::from_json(&v.to_string()).unwrap();
+    assert_eq!(radius.dimension(id).map(|r| &r.kind), Some(&radial(false)));
+    assert_eq!(dim(&mut file(&radius), &radial_id)["kind"]["radial"].get("diameter"), None, "a radius, not written");
+    let names = format!("damaged drawing: dimension {radial_id}: a name in a reference is 1 to 512 bytes, without control characters");
+    assert_eq!(refused(&d, |v| dim(v, &radial_id)["kind"]["radial"]["edge"]["name"] = json!("")), names);
+    assert!(refused(&d, |v| dim(v, &radial_id)["kind"]["radial"]["reading"] = json!("true")).starts_with("damaged drawing: "));
+}
+
+/// A chain saves its points in order and its direction, and keeps its rules on reading: 3 to
+/// [`MAX_CHAIN_POINTS`] points, each with a point's rules, a direction to measure along that isn't
+/// zero, no reading (it reads projected) and no text instead of its members' numbers.
+#[test]
+fn a_chain_saves_its_points_in_order_and_keeps_its_rules() {
+    let (mut d, _) = measured();
+    let (view, id) = (d.views[0].id, d.allocate_id(&mut IdSource::seeded(SEED + 1)).unwrap());
+    let hole = |n: u64| {
+        let rim = format!("F{n}:hole|F1:front");
+        ModelPoint { centre: true, ..corner(&[rim.as_str()]) }
+    };
+    let points = vec![corner(&["F1:front|F1:bottom", "F1:front|F1:left"]), hole(3), hole(4), hole(5)];
+    let kind = DimensionKind::Chain { points, direction: LinearDirection::Horizontal };
+    d.add_dimensions([Arc::new(Dimension {
+        id,
+        view,
+        kind,
+        offset_mm: 8.0,
+        text: TextPlace::Centred,
+        decimals: 1,
+        override_text: None,
+        last_good: None,
+    })]);
+    d.validate().unwrap();
+    let chain_id = ids::encode(id);
+    let mut v = file(&d);
+    let first = json!({"body": "Box", "origin_feature": 7, "edges": ["F1:front|F1:bottom", "F1:front|F1:left"]});
+    let centre = |n: u64| json!({"body": "Box", "origin_feature": 7, "edges": [format!("F{n}:hole|F1:front")], "centre": true});
+    let saved = json!({"chain": {"points": [first, centre(3), centre(4), centre(5)], "direction": "horizontal"}});
+    assert_eq!(dim(&mut v, &chain_id)["kind"], saved);
+    assert_eq!(Drawing::from_json(&v.to_string()).unwrap(), d);
+    let rule = |rule: &str| format!("damaged drawing: dimension {chain_id}: {rule}");
+    let count = |n: usize| {
+        refused(&d, |v| {
+            let points = &mut dim(v, &chain_id)["kind"]["chain"]["points"];
+            let one = points[1].clone();
+            *points = json!(vec![one; n]);
+        })
+    };
+    let three_to = rule(&format!("a chain has 3 to {MAX_CHAIN_POINTS} points"));
+    let counts = [count(0), count(2), count(3), count(MAX_CHAIN_POINTS), count(MAX_CHAIN_POINTS + 1)];
+    assert_eq!(counts, [three_to.clone(), three_to.clone(), "read".into(), "read".into(), three_to]);
+    let two_edges = refused(&d, |v| dim(v, &chain_id)["kind"]["chain"]["points"][2]["edges"] = json!(["F3:a", "F3:b"]));
+    assert_eq!(two_edges, rule("a centre is of one named circle or arc"));
+    let zero = refused(&d, |v| dim(v, &chain_id)["kind"]["chain"]["direction"] = json!({"along": [0.0, 0.0]}));
+    assert_eq!(zero, rule("the direction to measure along is zero or not finite"));
+    let instead = refused(&d, |v| dim(v, &chain_id)["override_text"] = json!("60"));
+    assert_eq!(instead, rule("a chain shows its members' numbers, never a text instead"));
+    let reading = refused(&d, |v| dim(v, &chain_id)["kind"]["chain"]["reading"] = json!("projected"));
+    assert!(reading.starts_with("damaged drawing: "), "{reading}");
+}
+
+/// A cylinder dimension saves its face by name, and the face keeps a reference's rules.
+#[test]
+fn a_cylinder_dimension_saves_its_face() {
+    let (mut d, _) = measured();
+    let (view, id) = (d.views[0].id, d.allocate_id(&mut IdSource::seeded(SEED + 1)).unwrap());
+    let face = ModelFace { body: BODY.into(), origin_feature: FEATURE, name: "F4:boss".into(), path: vec![3] };
+    let kind = DimensionKind::Cylinder { face };
+    d.add_dimensions([Arc::new(Dimension {
+        id,
+        view,
+        kind,
+        offset_mm: 6.0,
+        text: TextPlace::Centred,
+        decimals: 1,
+        override_text: None,
+        last_good: None,
+    })]);
+    d.validate().unwrap();
+    let cylinder = ids::encode(id);
+    let mut v = file(&d);
+    let saved = json!({"cylinder": {"face": {"body": "Box", "origin_feature": 7, "name": "F4:boss", "path": [3]}}});
+    assert_eq!(dim(&mut v, &cylinder)["kind"], saved);
+    assert_eq!(Drawing::from_json(&v.to_string()).unwrap(), d);
+    let rule = |rule: &str| format!("damaged drawing: dimension {cylinder}: {rule}");
+    let changed = |key: &str, value: Value| refused(&d, |v| dim(v, &cylinder)["kind"]["cylinder"]["face"][key] = value);
+    assert_eq!(changed("name", json!("")), rule("a name in a reference is 1 to 512 bytes, without control characters"));
+    assert_eq!(changed("origin_feature", json!(0)), rule("a reference names the feature that made its body"));
+    assert_eq!(changed("path", json!([0])), rule("an occurrence path is at most 64 occurrences, none of them 0"));
+    assert!(changed("edges", json!(["F4:boss"])).starts_with("damaged drawing: "), "a face has no edges");
+}
+
+/// A dimension between two cylinders' silhouettes saves each one's face and side, and its
+/// direction; each face keeps a reference's rules, a side is near or far, and it reads as the view
+/// shows it (no `reading`).
+#[test]
+fn a_silhouettes_dimension_saves_each_face_and_side() {
+    let (mut d, _) = measured();
+    let (view, id) = (d.views[0].id, d.allocate_id(&mut IdSource::seeded(SEED + 1)).unwrap());
+    let face = |name: &str| ModelFace { body: BODY.into(), origin_feature: FEATURE, name: name.into(), path: Vec::new() };
+    let (a, b) = (Silhouette { face: face("F4:boss"), side: SilhouetteSide::Near }, Silhouette { face: face("F5:pin"), side: SilhouetteSide::Far });
+    let kind = DimensionKind::Silhouettes { a, b, direction: LinearDirection::Vertical };
+    d.add_dimensions([Arc::new(Dimension {
+        id,
+        view,
+        kind,
+        offset_mm: 6.0,
+        text: TextPlace::Centred,
+        decimals: 1,
+        override_text: None,
+        last_good: None,
+    })]);
+    d.validate().unwrap();
+    let silhouettes = ids::encode(id);
+    let mut v = file(&d);
+    let face = |name: &str| json!({"body": "Box", "origin_feature": 7, "name": name});
+    let saved = json!({"silhouettes": {"a": {"face": face("F4:boss"), "side": "near"}, "b": {"face": face("F5:pin"), "side": "far"}, "direction": "vertical"}});
+    assert_eq!(dim(&mut v, &silhouettes)["kind"], saved);
+    assert_eq!(Drawing::from_json(&v.to_string()).unwrap(), d);
+    let rule = |rule: &str| format!("damaged drawing: dimension {silhouettes}: {rule}");
+    let changed = |edit: &dyn Fn(&mut Value)| refused(&d, |v| edit(&mut dim(v, &silhouettes)["kind"]["silhouettes"]));
+    assert_eq!(changed(&|k| k["b"]["face"]["name"] = json!("")), rule("a name in a reference is 1 to 512 bytes, without control characters"));
+    assert_eq!(changed(&|k| k["a"]["face"]["origin_feature"] = json!(0)), rule("a reference names the feature that made its body"));
+    assert_eq!(changed(&|k| k["direction"] = json!({"along": [0.0, 0.0]})), rule("the direction to measure along is zero or not finite"));
+    let malformed: [fn(&mut Value); 3] = [|k| k["a"]["side"] = json!("left"), |k| k["reading"] = json!("true"), |k| k["b"]["edges"] = json!([])];
+    for edit in malformed {
+        let why = changed(&edit);
+        assert!(why.starts_with("damaged drawing: "), "{why}");
+    }
+}
+
+/// A direction along a picked line saves as its plane coordinates and reads back as the same
+/// direction: what W19a measures along.
+#[test]
+fn a_direction_along_a_line_saves_as_its_coordinates() {
+    let along = LinearDirection::Along(Vec2::new(0.6, 0.8));
+    assert_eq!(serde_json::to_value(along).unwrap(), json!({"along": [0.6, 0.8]}));
+    assert_eq!(serde_json::from_value::<LinearDirection>(json!({"along": [0.6, 0.8]})).unwrap(), along);
+    assert_eq!(serde_json::to_value(Reading::True).unwrap(), json!("true"));
+}
+
+/// A last good value saves only when there is one, reads back as saved, and an older drawing reads
+/// with none.
+#[test]
+fn a_last_good_value_saves_only_when_there_is_one() {
+    let (mut d, [linear, ..]) = measured();
+    let id = ids::encode(linear);
+    assert_eq!(dim(&mut file(&d), &id).get("last_good"), None, "none: not written");
+    let at = d.dimension_index(linear).unwrap();
+    Arc::make_mut(&mut d.dimensions[at]).last_good = Some(80.5);
+    let mut v = file(&d);
+    assert_eq!(dim(&mut v, &id)["last_good"], json!(80.5));
+    let read = Drawing::from_json(&v.to_string()).unwrap();
+    assert_eq!(read, d);
+    assert_eq!(read.to_json().unwrap(), d.to_json().unwrap(), "the same bytes again");
+    dim(&mut v, &id).as_object_mut().unwrap().remove("last_good");
+    assert_eq!(Drawing::from_json(&v.to_string()).unwrap().dimension(linear).unwrap().last_good, None);
+}
+
+/// A last good value is from 0 to the largest number a drawing saves; a file with any other is
+/// refused, and so is a record built with one that JSON can't hold.
+#[test]
+fn a_last_good_value_keeps_its_rule() {
+    let (d, [linear, ..]) = measured();
+    let id = ids::encode(linear);
+    let with = |value: Value| refused(&d, |v| dim(v, &id)["last_good"] = value);
+    for good in [json!(0.0), json!(-0.0), json!(5e-324), json!(80), json!(MAX_REAL)] {
+        assert_eq!(with(good.clone()), "read", "{good}");
+    }
+    for bad in [json!(-5e-324), json!(-1.0)] {
+        assert!(with(bad.clone()).contains("last good"), "{bad}: {}", with(bad.clone()));
+    }
+    // Past every drawing's largest number: the file's own check refuses it first.
+    let past = MAX_REAL * (1.0 + f64::EPSILON);
+    for bad in [json!(past), json!(f64::MAX), json!(-f64::MAX)] {
+        assert_ne!(with(bad.clone()), "read", "{bad}");
+    }
+    let mut direct = d.clone();
+    Arc::make_mut(&mut direct.dimensions[0]).last_good = Some(past);
+    assert!(direct.validate().is_err());
+    for bad in [f64::NAN, f64::INFINITY, f64::NEG_INFINITY] {
+        let mut direct = d.clone();
+        Arc::make_mut(&mut direct.dimensions[0]).last_good = Some(bad);
+        assert!(direct.validate().is_err(), "{bad}");
+    }
+}
+
+/// What dimensions last read goes into their records by drawing and dimension, leaving out a
+/// dimension or a drawing no longer there and a value the record would refuse. A drawing with no
+/// new value stays shared with the document it was copied from, and that document keeps none.
+#[test]
+fn keep_last_good_keeps_only_what_a_record_may_save() {
+    let (first, [a, b, c]) = measured();
+    let second = Drawing { id: first.id + 1, ..first.clone() };
+    let (one, two) = (first.id, second.id);
+    let mut doc = Document::new("Box");
+    doc.drawings = vec![Arc::new(first), Arc::new(second)];
+    let before = doc.clone();
+    let values = BTreeMap::from([
+        ((one, a), 80.0),
+        ((one, b), MAX_REAL),
+        ((one, c), MAX_REAL * 2.0),
+        ((one, 1), 5.0),
+        ((one, u64::MAX), 5.0),
+        ((two + 1, a), 5.0),
+    ]);
+    doc.keep_last_good(&values);
+    let read = |doc: &Document, drawing: usize, id| doc.drawings[drawing].dimension(id).unwrap().last_good;
+    assert_eq!([read(&doc, 0, a), read(&doc, 0, b), read(&doc, 0, c)], [Some(80.0), Some(MAX_REAL), None]);
+    assert_eq!([read(&doc, 1, a), read(&doc, 1, b), read(&doc, 1, c)], [None; 3], "another drawing's dimensions, with the same ids");
+    assert!(Arc::ptr_eq(&doc.drawings[1], &before.drawings[1]), "no new value: still shared");
+    assert_eq!(read(&before, 0, a), None, "the document it was copied from keeps none");
+    doc.drawings.iter().for_each(|d| d.validate().unwrap());
+    let kept = doc.clone();
+    doc.keep_last_good(&values);
+    assert!(Arc::ptr_eq(&doc.drawings[0], &kept.drawings[0]), "the same values again: still shared");
+}
+
+/// Whatever a read hands over, at every boundary and over random bit patterns, the saved record is
+/// one a file can open: a design is never lost to its last good values.
+#[test]
+fn keep_last_good_never_writes_a_record_a_file_refuses() {
+    let (d, [linear, ..]) = measured();
+    let id = d.id;
+    let mut doc = Document::new("Box");
+    doc.drawings = vec![Arc::new(d)];
+    let tricky = [0.0, -0.0, 5e-324, MAX_REAL, MAX_REAL * (1.0 + f64::EPSILON), -1.0, 1e12, f64::MAX, f64::NAN, f64::INFINITY, f64::NEG_INFINITY];
+    let mut bits = 0x9E37_79B9_7F4A_7C15_u64;
+    let random = std::iter::repeat_with(|| {
+        bits = bits.wrapping_mul(0x5851_F42D_4C95_7F2D).wrapping_add(1);
+        f64::from_bits(bits)
+    });
+    for value in tricky.into_iter().chain(random.take(2000)) {
+        doc.keep_last_good(&BTreeMap::from([((id, linear), value)]));
+        let saved = doc.drawings[0].to_json().unwrap();
+        let read = Drawing::from_json(&saved).unwrap_or_else(|e| panic!("{value}: {e}"));
+        assert_eq!(read.dimension(linear).unwrap().last_good, doc.drawings[0].dimension(linear).unwrap().last_good, "{value}");
+    }
+}
+
+/// A lost edge's leads, from its body's face names: the blend face that rounds it and a piece of that
+/// face (a later cut's), then the edges they bound, then the faces of the feature that made it, at most
+/// 16, no face twice. Another fillet's face rounds another edge, so it leads nowhere. A `~k` on the
+/// name finds the same blend; a name no blend rounds leads to its makers' faces only, as a face's
+/// does, and a name that doesn't read, or whose feature made nothing here, leads nowhere.
+#[test]
+fn lost_leads_list_the_blend_then_its_edges_then_the_makers_faces() {
+    let blends = ["F5:blend:F1:+z|F1:-y", "F5:blend:F1:+z|F1:-y#[F1:+x,F7:+z]", "F6:blend:F1:+x|F1:+z"];
+    let mut faces: Vec<String> = ["F1:+z", "F1:-y", "F1:+x"].into_iter().chain(blends).map(String::from).collect();
+    faces.extend((0..40).map(|k| format!("F1:face:{k}")));
+    let leads = Leads::new(BODY, &faces);
+    // Edges 0, 1, 3 and 5 bound the blend or its piece; 2 and 4 don't.
+    let edge_faces = [vec![0, 3], vec![1, 3], vec![0, 2], vec![3, 4], vec![2, 5], vec![4, 1]];
+    let lead_face = |index: usize| Candidate::Face { body: BODY.into(), index };
+    let lead_edge = |index: usize| Candidate::Edge { body: BODY.into(), index };
+    let box_faces = |n: usize| [0, 1, 2].into_iter().chain(6..).take(n).map(lead_face);
+    let mut expected = vec![lead_face(3), lead_face(4), lead_edge(0), lead_edge(1), lead_edge(3), lead_edge(5)];
+    expected.extend(box_faces(10));
+    let found = leads.for_edge("F1:+z|F1:-y", &edge_faces);
+    assert_eq!(found, expected);
+    assert_eq!(found.len(), MAX_CANDIDATES);
+    assert_eq!(leads.for_edge("F1:+z|F1:-y~2", &edge_faces), expected, "a numbered edge's blend");
+    let makers: Vec<Candidate> = box_faces(MAX_CANDIDATES).collect();
+    assert_eq!(leads.for_edge("F1:-y|F1:+x", &edge_faces), makers, "no blend rounds it");
+    assert_eq!(leads.for_face("F1:+z"), makers, "a face's");
+    assert!(leads.for_edge("F1:+z|", &edge_faces).is_empty(), "a name that doesn't read");
+    assert!(leads.for_edge("F9:+z|F9:-y", &edge_faces).is_empty(), "a feature that made nothing here");
+}
+
+/// Quarter arcs of radius `r` round `c` in the plane z = 0, from `from` degrees, as a tessellated edge.
+fn arc_at(c: [f64; 2], r: f64, from: f64) -> (usize, Vec<Vec3>) {
+    let at = |d: f64| Vec3::new(c[0] + r * (from + d).to_radians().cos(), c[1] + r * (from + d).to_radians().sin(), 0.0);
+    (0, (0..=9).map(|i| at(f64::from(i) * 10.0)).collect())
+}
+
+/// Pieces are one circle only when every one lies on it: another centre or radius, however near, is
+/// another circle, and a straight piece isn't a circle. Pieces too short to read a circle from alone
+/// are read together, so short arcs of one circle are it and of two circles aren't; a piece of only
+/// two points could be a chord, and no pieces are none.
+#[test]
+fn pieces_are_one_circle_only_when_they_all_lie_on_it() {
+    let c = [40.0, 15.0];
+    let first = arc_at(c, 6.0, 0.0);
+    let found = one_circle(&[first.clone(), arc_at(c, 6.0, 180.0)]).unwrap();
+    assert!(found.dist(Vec3::new(40.0, 15.0, 0.0)) < 1e-9, "{found:?}");
+    assert!(one_circle(std::slice::from_ref(&first)).is_some());
+    assert!(one_circle(&[first.clone(), arc_at([40.0 + 1e-9, 15.0], 6.0, 180.0)]).is_some(), "rounding is the same circle");
+    assert!(one_circle(&[first.clone(), arc_at([40.0 + 1e-3, 15.0], 6.0, 180.0)]).is_none(), "another centre");
+    assert!(one_circle(&[first.clone(), arc_at(c, 6.0 + 1e-3, 180.0)]).is_none(), "another radius");
+    let above: Vec<Vec3> = arc_at(c, 6.0, 180.0).1.iter().map(|p| Vec3::new(p.x, p.y, 5.0)).collect();
+    assert!(one_circle(&[first.clone(), (1, above)]).is_none(), "the same circle moved along its axis");
+    let tilted: Vec<Vec3> = arc_at(c, 6.0, 180.0).1.iter().map(|p| Vec3::new(40.0, p.y, p.x - 40.0)).collect();
+    assert!(one_circle(&[first.clone(), (1, tilted)]).is_none(), "round another axis");
+    let line: Vec<Vec3> = (0..5).map(|i| Vec3::new(f64::from(i), 0.0, 0.0)).collect();
+    assert!(one_circle(&[first.clone(), (1, line)]).is_none(), "a straight piece");
+    assert!(one_circle(&[first.clone(), (1, first.1[..3].to_vec())]).is_some(), "too short to read, but on it");
+    let off: Vec<Vec3> = first.1[..3].iter().map(|p| Vec3::new(p.x + 1e-3, p.y, p.z)).collect();
+    assert!(one_circle(&[first.clone(), (1, off)]).is_none(), "too short to read, and off it");
+    assert!(one_circle(&[first.clone(), (1, first.1[..2].to_vec())]).is_none(), "two points could be a chord");
+    let short = |c: [f64; 2]| (1, arc_at(c, 6.0, 180.0).1[..3].to_vec());
+    let three = (0, first.1[..3].to_vec());
+    assert!(one_circle(&[three.clone(), short(c)]).is_some(), "short arcs of one circle, read together");
+    assert!(one_circle(&[three, short([45.0, 15.0])]).is_none(), "short arcs of two circles of one radius");
+    assert!(one_circle(&[]).is_none());
+}

crates/doc/src/drawing/fields.rs

@@ -0,0 +1,144 @@
+//! A title block's fields (#3875): the keys each source has, and what they read. Stateless: the
+//! drawing gives its own fields, its sheets' and its newest revision's, and the caller hands in the
+//! component a sheet documents with what the model says of it (its material and mass, worked out
+//! by the bill of materials). A key its source doesn't have is refused when a block is given or
+//! read; a value that isn't there, or is empty, shows [`MISSING`]. Sheet tables' cells (B3) read
+//! the same fields.
+//!
+//! - **component:** `name`, `part_number`, `description`, `revision` (its part properties),
+//!   `material`, `mass`, and `properties.<name>` (its free-text properties, such as a finish);
+//! - **drawing:** `name`, `number` (its `part_number` property: the drawing's identification
+//!   number; without one, the name of the component the sheet documents), `organization`, `author`,
+//!   `project`, and `properties.<key>` (any of its properties);
+//! - **sheet:** `name`, `number`, `count`: sheets left out of the count are neither counted nor
+//!   numbered, and such a sheet shows neither;
+//! - **revision:** the newest revision row's fields ([`Field`]);
+//! - **prompt:** any key; answers come with templates, so a prompt shows [`MISSING`] until then.
+
+use solidcraft_geom::cell::{Content, MISSING, Part, Source};
+use solidcraft_geom::revision::Field;
+use solidcraft_geom::title_block::{CellKind, TitleBlock};
+
+use super::Drawing;
+use crate::{DocError, Metadata, Result};
+
+const COMPONENT: [&str; 6] = ["name", "part_number", "description", "revision", "material", "mass"];
+const DRAWING: [&str; 5] = ["name", "number", "organization", "author", "project"];
+const SHEET: [&str; 3] = ["name", "number", "count"];
+/// Before a property's name: the field reads that property.
+const PROPERTIES: &str = "properties.";
+
+/// The component a sheet documents, as its fields read it.
+#[derive(Clone, Copy, Debug)]
+pub struct Component<'a> {
+    pub name: &'a str,
+    /// Its part properties.
+    pub metadata: &'a Metadata,
+    /// Its free-text properties (the design's own: none).
+    pub properties: Option<&'a std::collections::BTreeMap<String, String>>,
+    /// What it is made of, as its bill of materials row would say: none when nothing is assigned.
+    pub material: Option<&'a str>,
+    /// What one of it weighs, written for the sheet: none when it can't be weighed.
+    pub mass: Option<&'a str>,
+}
+
+/// Whether `source` has the field `key`.
+pub fn has_key(source: Source, key: &str) -> bool {
+    let property = key.strip_prefix(PROPERTIES).is_some_and(|name| !name.is_empty());
+    match source {
+        Source::Component => COMPONENT.contains(&key) || property,
+        Source::Drawing => DRAWING.contains(&key) || property,
+        Source::Sheet => SHEET.contains(&key),
+        Source::Revision => Field::ALL.iter().any(|f| f.key() == key),
+        Source::Prompt => !key.is_empty(),
+        Source::Row => false,
+    }
+}
+
+/// Whether `block` has a text cell `name`: what a sheet's override may name.
+pub fn overridable(block: Option<&TitleBlock>, name: &str) -> bool {
+    block.is_some_and(|block| block.cells.iter().any(|cell| cell.name == name && matches!(cell.kind, CellKind::Text(_))))
+}
+
+/// Each field of `block` names a key its source has: what a sheet holds its block to.
+pub fn check_block(block: &TitleBlock) -> Result<()> {
+    for cell in &block.cells {
+        let CellKind::Text(text) = &cell.kind else { continue };
+        for part in &text.content.0 {
+            if let Part::Field { source, key, .. } = part
+                && !has_key(*source, key)
+            {
+                let source = serde_json::to_value(source).ok().and_then(|v| v.as_str().map(str::to_string)).unwrap_or_default();
+                return Err(DocError::Invalid(format!("cell `{}`: the {source} has no field `{key}`", cell.name)));
+            }
+        }
+    }
+    Ok(())
+}
+
+/// What a sheet's fields read: its drawing, its place among the drawing's sheets, and the component
+/// it documents.
+#[derive(Clone, Copy, Debug)]
+pub struct Values<'a> {
+    pub drawing: &'a Drawing,
+    pub sheet: usize,
+    pub component: Option<Component<'a>>,
+}
+
+impl Values<'_> {
+    /// `content` as its cell shows it: text as written, each field its value or [`MISSING`].
+    pub fn text(&self, content: &Content) -> String {
+        let part = |part: &Part| match part {
+            Part::Text(text) => text.clone(),
+            Part::Field { source, key, .. } => self.field(*source, key).filter(|v| !v.is_empty()).unwrap_or_else(|| MISSING.into()),
+        };
+        content.0.iter().map(part).collect()
+    }
+
+    /// The field `key` of `source`, when it has a value.
+    fn field(&self, source: Source, key: &str) -> Option<String> {
+        let d = self.drawing;
+        let property = |metadata: &Metadata| key.strip_prefix(PROPERTIES).and_then(|name| metadata.text(name)).map(str::to_string);
+        match source {
+            Source::Drawing => match key {
+                "name" => Some(d.name.clone()),
+                "number" => d.properties.part_number().or(self.component.map(|c| c.name)).map(str::to_string),
+                "organization" | "author" | "project" => d.properties.text(key).map(str::to_string),
+                _ => property(&d.properties),
+            },
+            Source::Sheet => {
+                let sheet = d.sheets.get(self.sheet)?;
+                if sheet.excluded.count {
+                    return (key == "name").then(|| sheet.name.clone());
+                }
+                let counted = |s: &&std::sync::Arc<super::Sheet>| !s.excluded.count;
+                match key {
+                    "name" => Some(sheet.name.clone()),
+                    "number" => Some((d.sheets.iter().take(self.sheet).filter(counted).count() + 1).to_string()),
+                    "count" => Some(d.sheets.iter().filter(counted).count().to_string()),
+                    _ => None,
+                }
+            }
+            Source::Revision => {
+                // The newest row in the sheet's scope: the drawing's, or the sheet's own once rows are per sheet.
+                let scope = if d.revisions.per_sheet { Some(d.sheets.get(self.sheet)?.id) } else { None };
+                d.revisions.newest(scope)?.field(key).map(str::to_string)
+            }
+            Source::Component => {
+                let c = self.component?;
+                match key {
+                    "name" => Some(c.name.to_string()),
+                    "material" => c.material.map(str::to_string),
+                    "mass" => c.mass.map(str::to_string),
+                    "part_number" | "description" | "revision" => c.metadata.text(key).map(str::to_string),
+                    _ => key.strip_prefix(PROPERTIES).and_then(|name| c.properties?.get(name)).cloned(),
+                }
+            }
+            Source::Prompt | Source::Row => None,
+        }
+    }
+}
+
+#[cfg(test)]
+#[path = "fields_tests.rs"]
+mod tests;

crates/doc/src/drawing/fields_tests.rs

@@ -0,0 +1,140 @@
+use std::collections::{BTreeMap, BTreeSet};
+use std::sync::Arc;
+
+use serde_json::json;
+use solidcraft_geom::cell::Format;
+use solidcraft_geom::drawing_sheet::{self, DrawingBorderProfile, Orientation, PaperSize};
+use solidcraft_geom::title_block::default_block;
+
+use super::*;
+use crate::drawing::Sheet;
+use crate::ids::IdSource;
+use crate::metadata::Owner;
+
+/// A drawing of three A3 sheets, each with the built-in block.
+fn drawing() -> Drawing {
+    let mut ids = IdSource::seeded(3875);
+    let a3 = drawing_sheet::Sheet::standard(PaperSize::A3, Orientation::Landscape);
+    let mut d = Drawing::new("Bracket drawing", "en", "Sheet 1", a3, Some(DrawingBorderProfile::iso()), &BTreeSet::new(), &mut ids).unwrap();
+    Arc::make_mut(&mut d.sheets[0]).title_block = Some(default_block());
+    for n in 2..=3 {
+        let id = d.allocate_id(&mut ids).unwrap();
+        d.sheets.push(Arc::new(Sheet { id, name: format!("Sheet {n}"), ..(*d.sheets[0]).clone() }));
+    }
+    d.validate().unwrap();
+    d
+}
+
+fn field(source: Source, key: &str) -> Part {
+    Part::Field { source, key: key.into(), format: Format::default() }
+}
+
+fn shown(d: &Drawing, sheet: usize, component: Option<Component>, parts: Vec<Part>) -> String {
+    Values { drawing: d, sheet, component }.text(&Content(parts))
+}
+
+/// The drawing's own fields: its name, its number (its part number property), its organization
+/// and any property; a property taken away shows nothing, never the value it had.
+#[test]
+fn the_drawings_fields() {
+    let mut d = drawing();
+    let properties = Arc::make_mut(&mut d.properties);
+    properties.set(Owner::Design, "part_number", json!("DRW-0042")).unwrap();
+    properties.set(Owner::Design, "organization", json!("Tangency Labs")).unwrap();
+    let parts = vec![
+        field(Source::Drawing, "name"),
+        Part::Text(" / ".into()),
+        field(Source::Drawing, "number"),
+        Part::Text(" / ".into()),
+        field(Source::Drawing, "organization"),
+    ];
+    assert_eq!(shown(&d, 0, None, parts.clone()), "Bracket drawing / DRW-0042 / Tangency Labs");
+    Arc::make_mut(&mut d.properties).remove("organization");
+    assert_eq!(shown(&d, 0, None, parts), "Bracket drawing / DRW-0042 / ");
+    assert_eq!(shown(&d, 0, None, vec![field(Source::Drawing, "properties.acme.finish")]), "");
+    // Without a number of its own, the drawing is numbered by the component its sheet documents,
+    // by name; without either, nothing.
+    let metadata = Metadata::default();
+    let bracket = Component { name: "Bracket", metadata: &metadata, properties: None, material: None, mass: None };
+    let number = || vec![field(Source::Drawing, "number")];
+    assert_eq!(shown(&d, 0, Some(bracket), number()), "DRW-0042", "its own number first");
+    Arc::make_mut(&mut d.properties).set(Owner::Design, "part_number", json!("")).unwrap();
+    assert_eq!(shown(&d, 0, Some(bracket), number()), "Bracket");
+    assert_eq!(shown(&d, 0, None, number()), "");
+}
+
+/// Sheets are numbered among the counted ones: the second of three is "2/3". A sheet left out of
+/// the count shows neither, and the sheets after it close up.
+#[test]
+fn sheets_are_numbered_among_the_counted_ones() {
+    let mut d = drawing();
+    let sheet = || vec![field(Source::Sheet, "number"), Part::Text("/".into()), field(Source::Sheet, "count")];
+    assert_eq!(shown(&d, 1, None, sheet()), "2/3");
+    Arc::make_mut(&mut d.sheets[1]).excluded.count = true;
+    assert_eq!([0, 1, 2].map(|at| shown(&d, at, None, sheet())), ["1/2", "/", "2/2"]);
+    assert_eq!(shown(&d, 1, None, vec![field(Source::Sheet, "name")]), "Sheet 2");
+}
+
+/// The revision fields read the newest row; with none, nothing.
+#[test]
+fn revision_fields_read_the_newest_row() {
+    let mut d = drawing();
+    let date = || vec![field(Source::Revision, "revision"), Part::Text(" ".into()), field(Source::Revision, "date")];
+    assert_eq!(shown(&d, 0, None, date()), " ");
+    let revisions = Arc::make_mut(&mut d.revisions);
+    for (id, day) in [(901, "2026-10-01"), (902, "2026-10-30")] {
+        revisions.add(None, id).unwrap();
+        revisions.set(id, Field::Date, day).unwrap();
+    }
+    assert_eq!(shown(&d, 0, None, date()), "2 2026-10-30");
+}
+
+/// A component's fields: its name and part properties, its free-text properties, and the material
+/// and mass the caller worked out; without a component, or a value, or with an empty one, nothing.
+#[test]
+fn the_components_fields() {
+    let d = drawing();
+    let mut metadata = Metadata::default();
+    metadata.set(Owner::Component, "part_number", json!("BRK-7")).unwrap();
+    let properties = BTreeMap::from([("finish".to_string(), "Zinc plated".to_string())]);
+    let bracket = Component { name: "Bracket", metadata: &metadata, properties: Some(&properties), material: Some("Steel"), mass: Some("0.39 kg") };
+    let keys = ["name", "part_number", "material", "mass", "properties.finish", "description"];
+    let read = |component| keys.map(|key| shown(&d, 0, component, vec![field(Source::Component, key)]));
+    assert_eq!(read(Some(bracket)), ["Bracket", "BRK-7", "Steel", "0.39 kg", "Zinc plated", ""]);
+    let unweighed = Component { material: None, mass: None, properties: None, ..bracket };
+    assert_eq!(read(Some(unweighed)), ["Bracket", "BRK-7", "", "", "", ""]);
+    assert_eq!(read(None), [""; 6]);
+    let blank = BTreeMap::from([("finish".to_string(), String::new())]);
+    let finish = vec![field(Source::Component, "properties.finish")];
+    assert_eq!(shown(&d, 0, Some(Component { properties: Some(&blank), ..bracket }), finish), "");
+}
+
+/// A field its source doesn't have is refused when a block is given and when a drawing is read,
+/// naming the cell; so is an override of a cell the block doesn't have or that shows no text, or
+/// one with a control character. A sheet without overrides saves none.
+#[test]
+fn unknown_fields_and_overrides_are_refused() {
+    let mut block = default_block();
+    let CellKind::Text(text) = &mut block.cells[8].kind else { panic!("the mass cell has text") };
+    text.content = Content(vec![field(Source::Component, "weight")]);
+    assert_eq!(check_block(&block).unwrap_err().to_string(), "cell `mass`: the component has no field `weight`");
+    let mut d = drawing();
+    let saved = d.to_json().unwrap();
+    assert!(!saved.contains("title_block_overrides"));
+    let mut v: serde_json::Value = serde_json::from_str(&saved).unwrap();
+    v["sheets"][0]["title_block"] = serde_json::to_value(&block).unwrap();
+    let refusal = Drawing::from_json(&v.to_string()).unwrap_err().to_string();
+    assert!(refusal.contains("cell `mass`: the component has no field `weight`"), "{refusal}");
+    // Overrides: a cell's name, a cell's text.
+    Arc::make_mut(&mut d.sheets[0]).title_block_overrides.insert("material".into(), "See note 3".into());
+    let saved = d.to_json().unwrap();
+    assert_eq!(Drawing::from_json(&saved).unwrap(), d);
+    let refusals =
+        [("weight", "x", "no text cell `weight`"), ("projection", "x", "no text cell `projection`"), ("material", "a\u{7}", "control character")];
+    for (cell, text, why) in refusals {
+        let mut wrong = d.clone();
+        Arc::make_mut(&mut wrong.sheets[0]).title_block_overrides.insert(cell.into(), text.into());
+        let refusal = wrong.validate().unwrap_err().to_string();
+        assert!(refusal.contains(why), "{refusal}");
+    }
+}

crates/doc/src/drawing/format/pending/README.md

@@ -1,7 +1,7 @@
 # Pending drawing-format changes
 
-One file per change to what a drawing file saves that no release has shipped yet. Drawings
-(`"format": "solidcraft-drawing/N"`, #3890) are versioned by the same code as designs
+One file per change to what a drawing saves (in its design's file) that no release has shipped
+yet. Drawings (`"format": "solidcraft-drawing/N"`, #3890) are versioned by the same code as designs
 (`crates/doc/src/format.rs`, `Family`), from their own first format, 1. Adding a file here is the
 whole format bump: never edit the `DRAWING` family in `format.rs`, another change's file or a
 `../v<N>/` folder.

crates/doc/src/drawing/format/pending/balloon-parts-list.rs

@@ -0,0 +1,3 @@
+//! A balloon can name the parts list it reads (`parts_list`, #3874), saved only when it does. An older
+//! balloon names none and reads its sheet's only list, else its drawing's. The last release refuses a
+//! drawing with this format's number.

crates/doc/src/drawing/format/pending/balloons.rs

@@ -0,0 +1,5 @@
+//! Drawings save their balloons (`balloons`, #3874 W26): each on one of the drawing's views, pointing
+//! at a placed part by a named edge of it (the edge's body, the feature that made it, its name and
+//! the occurrences the body is placed through), with its place on paper from the view's centre. An
+//! older drawing has no balloons. The last release refuses a drawing saved with them, as a newer
+//! format.

crates/doc/src/drawing/format/pending/dimension-faces.rs

@@ -0,0 +1,3 @@
+//! A drawing's dimension can measure between two flat faces (`faces`, #4892): each saved by its
+//! face's name, with the direction to measure along. An older drawing has none. The last release
+//! refuses a drawing saved with one, as a newer format.

crates/doc/src/drawing/format/pending/dimension-last-good.rs

@@ -0,0 +1,4 @@
+//! A drawing's dimensions save their last good value (`last_good`, W19d, #4896) when they have one:
+//! what the dimension last read, so one that can't be measured any more still says what it was
+//! after the design is reopened. An older drawing has none, and each dimension has one again from
+//! its next read. The last release refuses a drawing saved with them, as a newer format.

crates/doc/src/drawing/format/pending/dimensions.rs

@@ -0,0 +1,7 @@
+//! Drawings save their dimensions (`dimensions`, #4896 W19b): each on one of the drawing's views,
+//! measuring named corners, circles' and arcs' centres, edges or faces of the view's model (a
+//! linear distance, an edge's length, an angle, a circle's or an arc's radius or diameter, a chain
+//! of distances along one line, a cylinder's diameter between its silhouettes, or the distance
+//! between two cylinders' silhouettes), with how far its line sits from them and where its text
+//! sits on paper, its decimals and any text shown instead of its number. An older drawing has no
+//! dimensions. The last release refuses a drawing saved with them, as a newer format.

crates/doc/src/drawing/format/pending/font.rs

@@ -0,0 +1,3 @@
+//! Drawings save the font their text is set in (`font`, #4890): a font family's name, never a
+//! file. An older drawing has none, and is set in the built-in font. The last release refuses a
+//! drawing saved with one, as a newer format.

crates/doc/src/drawing/format/pending/images.rs

@@ -0,0 +1,4 @@
+//! Drawings save their images (#5426): `images` holds each file once, with its format, pixel size and
+//! bytes (base64), and `sheet_images` each place one sits, with its sheet, its rectangle and the file's
+//! id. The file's path is never saved. An older drawing has neither. The last release refuses a drawing
+//! saved with them, as a newer format.

crates/doc/src/drawing/format/pending/in-design.rs

@@ -0,0 +1,5 @@
+//! A drawing lives in the file of the design it draws (#3890): it has an `id`, unique among its
+//! design's drawings, and at most one source, the design it is in, which has an `id` and no `path`.
+//! No step: no release saved a drawing before this, and a drawing file of its own is no longer
+//! read, so an older drawing is refused as damaged. The last release refuses a design that holds a
+//! drawing (the design's newer format number).

crates/doc/src/drawing/format/pending/notes.rs

@@ -0,0 +1,3 @@
+//! Drawings save their notes (`notes`, #4896): each on a sheet, a view, or an edge or corner of a view's
+//! model, with its text and fields, its place and its text height. A leader is never saved. An older
+//! drawing has no notes. The last release refuses a drawing saved with them, as a newer format.

crates/doc/src/drawing/format/pending/revision-tags.rs

@@ -0,0 +1,3 @@
+//! A revision tag saves the sheet it sits on and its place there, `sheet` and `at`. No command wrote a
+//! tag before, so no step rewrites older drawings. The last release refuses a drawing with this
+//! format's number.

crates/doc/src/drawing/format/pending/revision-versions.rs

@@ -0,0 +1,4 @@
+//! An issued revision saves the design it was issued from as `model_version: {path, change}`, opaque
+//! text from the version history, on its issued copy only. It was a string that no command ever
+//! wrote, so no step rewrites older drawings. A row's issued copy keeps the row's id, one copy for
+//! each row. The last release refuses a drawing with this format's number.

crates/doc/src/drawing/format/pending/revisions.rs

@@ -0,0 +1,4 @@
+//! Drawings save their revisions (`revisions`, #3874): one revision record for the whole drawing,
+//! its rows (revision, description, designer, checker, date, hidden) in the order they were added,
+//! each with its id. An older drawing has no revisions. The last release refuses a drawing saved
+//! with them, as a newer format.

crates/doc/src/drawing/format/pending/sheet-cell-overrides.rs

@@ -0,0 +1,3 @@
+//! Drawing sheets save the text typed over their title block's cells (`title_block_overrides`,
+//! #3875), by cell name. An older drawing's sheets have none. The last release refuses a drawing
+//! saved with one, as a newer format.

crates/doc/src/drawing/format/pending/sheet-tables.rs

@@ -0,0 +1,3 @@
+//! Drawings save their tables (`tables`, #3874): each on one of the drawing's sheets, a parts list or
+//! a revision table, with its definition and its place. Rows are never saved. An older drawing has no
+//! tables. The last release refuses a drawing saved with them, as a newer format.

crates/doc/src/drawing/format/pending/sheet-title-block.rs

@@ -0,0 +1,3 @@
+//! Drawing sheets save a copy of their title block's definition (`title_block`, #3875 W18): its size,
+//! its two line widths and its cells, on the drawing border's lower-right corner. An older drawing's
+//! sheets have no title block. The last release refuses a drawing saved with one, as a newer format.

crates/doc/src/drawing/format/pending/sheet-views.rs

@@ -0,0 +1,5 @@
+//! Drawings save their views (`views`, #4816): base views of their designs and the views projected
+//! from them, on their sheets, each with the settings it sets itself; and the projection every
+//! projected view follows (`projection`: `first` or `third` angle). An older drawing has no views,
+//! and its projection is third angle. The last release refuses a drawing saved with them, as a
+//! newer format.

crates/doc/src/drawing/format/pending/table-column-printed.rs

@@ -0,0 +1,3 @@
+//! A table's column can be left off paper (`printed`, #3874), saved only when it is: a new parts list's
+//! ballooned column, for its editor alone. An older drawing's columns are all printed. The last release
+//! refuses a drawing with this format's number.

crates/doc/src/drawing/format/pending/view-occurrences.rs

@@ -0,0 +1,4 @@
+//! A drawing's views save what they show (`settings.occurrences` and `settings.hide`, #4816): the
+//! occurrence paths each draws and leaves out, followed down its projected views until one sets its
+//! own. An older drawing has neither, so each view draws every body the design places. The last
+//! release refuses a drawing saved with them, as a newer format.

crates/doc/src/drawing/image.rs

@@ -0,0 +1,156 @@
+//! A drawing's images (W38e, #5426): a PNG or JPEG placed on a sheet, such as a logo or a photo.
+//!
+//! - **A file and its placements are two records.** A logo sits on every sheet: [`Drawing::images`]
+//!   holds it once, and each [`SheetImage`] in [`Drawing::sheet_images`] says where one sits. A file
+//!   goes with the last thing that uses it ([`Drawing::images_in_use`]).
+//! - **The bytes** travel in the drawing's record (base64, as a canvas's do), so the design opens
+//!   without the original file, and the file's path is never saved.
+//! - **The caps** are checked from the file's bytes and header, before anything decodes its pixels:
+//!   a small file can claim to hold more pixels than memory has. The header can lie in the record
+//!   too, so reading a drawing compares the two ([`Drawing::check_image_files`]); an edit, which only
+//!   ever adds a checked file, doesn't decode them again.
+//!
+//! The rules, beside the record's: a file is used; a placement names a file the drawing has, and is
+//! on one of its sheets, in a rectangle on paper with a size; at most [`MAX_IMAGES`] files of at most
+//! [`MAX_IMAGE_BYTES`] and [`MAX_IMAGE_PIXELS`] each, and [`MAX_IMAGES_BYTES`] between them; at most
+//! [`MAX_SHEET_IMAGES`] placements; each list by id.
+
+use std::collections::BTreeSet;
+
+use serde::{Deserialize, Serialize};
+use solidcraft_geom::drawing_view::is_paper_coordinate;
+use solidcraft_geom::paper::{MAX_IMAGE_PIXELS, MAX_SIDE_MM};
+
+use super::by_id::Record;
+use super::{Drawing, require};
+use crate::canvas::{base64_decode, base64_encode, image_info};
+use crate::{DocError, Result, ids};
+
+/// The most image files a drawing may have.
+pub const MAX_IMAGES: usize = 1_000;
+/// The most placements of them a drawing may have.
+pub const MAX_SHEET_IMAGES: usize = 1_000;
+/// The largest file an image may be.
+pub const MAX_IMAGE_BYTES: usize = 4 << 20;
+/// The most a drawing's image files may be between them: two of the largest and some, whose 12 MiB
+/// of text leaves room under [`super::MAX_DRAWING_BYTES`] for the rest of the record.
+pub const MAX_IMAGES_BYTES: usize = 9 << 20;
+
+/// One image file of a drawing, however many places it sits.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct ImageFile {
+    #[serde(with = "crate::ids")]
+    pub id: u64,
+    /// `png` or `jpeg`, as the file's header says.
+    pub format: String,
+    /// Its width and height in pixels, as the file's header says.
+    pub pixels: [u32; 2],
+    /// The file, base64.
+    pub data: String,
+}
+
+/// One place an image file sits, on a sheet of a drawing.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct SheetImage {
+    #[serde(with = "crate::ids")]
+    pub id: u64,
+    #[serde(with = "crate::ids")]
+    pub sheet: u64,
+    /// Where it sits, `[x0, y0, x1, y1]` in millimetres from the sheet's lower-left corner.
+    pub rect_mm: [f64; 4],
+    /// The file it shows, by id.
+    #[serde(with = "crate::ids")]
+    pub image: u64,
+}
+
+/// The length of `bytes` bytes in base64.
+const fn encoded(bytes: usize) -> usize {
+    bytes.div_ceil(3) * 4
+}
+
+/// What a file's bytes and header say it is, when its caps allow it. Nothing is decoded.
+fn file_info(bytes: &[u8]) -> Result<(&'static str, [u32; 2])> {
+    require(bytes.len() <= MAX_IMAGE_BYTES, || format!("the file is over {} MiB", MAX_IMAGE_BYTES >> 20))?;
+    let (format, pixels) = image_info(bytes).ok_or_else(|| DocError::Invalid("the file isn't a PNG or JPEG".into()))?;
+    let [w, h] = pixels;
+    require(u64::from(w) * u64::from(h) <= MAX_IMAGE_PIXELS, || format!("the file has {w} by {h} pixels, over {MAX_IMAGE_PIXELS}"))?;
+    Ok((format, pixels))
+}
+
+impl ImageFile {
+    /// The image file of a file's `bytes`, when its caps allow it: nothing is decoded.
+    pub fn from_file(id: u64, bytes: &[u8]) -> Result<ImageFile> {
+        let (format, pixels) = file_info(bytes)?;
+        Ok(ImageFile { id, format: format.into(), pixels, data: base64_encode(bytes) })
+    }
+}
+
+impl Record for ImageFile {
+    fn id(&self) -> u64 {
+        self.id
+    }
+}
+
+impl Record for SheetImage {
+    fn id(&self) -> u64 {
+        self.id
+    }
+}
+
+impl Drawing {
+    /// The image files something in the drawing uses: the one list of what keeps a file. Anything new
+    /// that shows a file adds its own here.
+    pub fn images_in_use(&self) -> BTreeSet<u64> {
+        self.sheet_images.iter().map(|placement| placement.image).collect()
+    }
+
+    /// Takes out each image file nothing uses now.
+    pub(super) fn drop_unused_images(&mut self) {
+        let used = self.images_in_use();
+        self.images.retain(|file| used.contains(&file.id));
+    }
+
+    pub(super) fn check_images(&self) -> Result<()> {
+        // The placements first: one that names no file says so, before its file reads as unused.
+        self.sheet_images.check(MAX_SHEET_IMAGES, "placed image", |placement| self.check_sheet_image(placement))?;
+        let used = self.images_in_use();
+        self.images.check(MAX_IMAGES, "image", |file| {
+            check_image(file)?;
+            require(used.contains(&file.id), || "nothing uses it".into())
+        })?;
+        let total = self.images.iter().fold(0, |total: usize, i| total.saturating_add(i.data.len()));
+        require(total <= encoded(MAX_IMAGES_BYTES), || format!("a drawing's images are at most {} MiB between them", MAX_IMAGES_BYTES >> 20))
+    }
+
+    fn check_sheet_image(&self, i: &SheetImage) -> Result<()> {
+        require(self.images.by_id(i.image).is_some(), || format!("it shows image {}, which the drawing doesn't have", ids::encode(i.image)))?;
+        require(self.sheets.iter().any(|s| s.id == i.sheet), || format!("it is on sheet {}, which the drawing doesn't have", ids::encode(i.sheet)))?;
+        let [x0, y0, x1, y1] = i.rect_mm;
+        let on_paper = [x0, y0, x1, y1].into_iter().all(is_paper_coordinate);
+        require(on_paper && x0 < x1 && y0 < y1, || format!("its rectangle has a size and is at most {MAX_SIDE_MM} mm on paper"))
+    }
+
+    /// Each image's bytes are the file its record says: what reading a drawing checks once, as it
+    /// decodes the base64, so that nothing later trusts a size the file doesn't have.
+    pub(super) fn check_image_files(&self) -> Result<()> {
+        self.images.iter().try_for_each(|i| {
+            let bytes = base64_decode(&i.data).ok_or_else(|| DocError::Invalid(format!("image {}: its file isn't base64", ids::encode(i.id))))?;
+            let (format, pixels) = file_info(&bytes).map_err(|e| DocError::Invalid(format!("image {}: {e}", ids::encode(i.id))))?;
+            require(format == i.format && pixels == i.pixels, || format!("image {}: its record and its file disagree", ids::encode(i.id)))
+        })
+    }
+}
+
+/// A file's own rules, from its record alone: what every edit keeps, without decoding it.
+fn check_image(i: &ImageFile) -> Result<()> {
+    require(matches!(i.format.as_str(), "png" | "jpeg"), || "it is a PNG or a JPEG".into())?;
+    let [w, h] = i.pixels;
+    require(w > 0 && h > 0 && u64::from(w) * u64::from(h) <= MAX_IMAGE_PIXELS, || format!("it has 1 to {MAX_IMAGE_PIXELS} pixels"))?;
+    require(i.data.len() <= encoded(MAX_IMAGE_BYTES), || format!("its file is at most {} MiB", MAX_IMAGE_BYTES >> 20))
+}
+
+#[cfg(test)]
+#[path = "image_tests.rs"]
+mod tests;

crates/doc/src/drawing/image_tests.rs

@@ -0,0 +1,233 @@
+use std::collections::BTreeSet;
+use std::sync::Arc;
+
+use serde_json::{Value, json};
+use solidcraft_geom::drawing_sheet::{self, Orientation, PaperSize};
+
+use super::*;
+use crate::ids::IdSource;
+
+const RECT: [f64; 4] = [10.0, 20.0, 60.0, 45.0];
+
+/// A PNG's header, saying these pixels: all a cap reads.
+fn png(w: u32, h: u32) -> Vec<u8> {
+    let mut b = b"\x89PNG\r\n\x1a\n\0\0\0\rIHDR".to_vec();
+    b.extend(w.to_be_bytes());
+    b.extend(h.to_be_bytes());
+    b.extend([8, 6, 0, 0, 0]);
+    b
+}
+
+/// A JPEG's start, saying these pixels.
+fn jpeg(w: u16, h: u16) -> Vec<u8> {
+    let mut b = vec![0xFF, 0xD8, 0xFF, 0xC0, 0, 17, 8];
+    b.extend(h.to_be_bytes());
+    b.extend(w.to_be_bytes());
+    b.extend([0; 12]);
+    b
+}
+
+/// A drawing on one A3 sheet with one image of `bytes` placed on it: the drawing, the file's id and
+/// the placement's.
+fn pictured(bytes: &[u8]) -> (Drawing, u64, u64) {
+    let mut id_source = IdSource::seeded(5426);
+    let a3 = drawing_sheet::Sheet::standard(PaperSize::A3, Orientation::Landscape);
+    let mut d = Drawing::new("Pictured", "en", "Sheet 1", a3, None, &BTreeSet::new(), &mut id_source).unwrap();
+    let (file, placed) = (d.allocate_id(&mut id_source).unwrap(), d.allocate_id(&mut id_source).unwrap());
+    d.images.add([Arc::new(ImageFile::from_file(file, bytes).unwrap())]);
+    d.sheet_images.add([Arc::new(SheetImage { id: placed, sheet: d.sheets[0].id, rect_mm: RECT, image: file })]);
+    d.validate().unwrap();
+    (d, file, placed)
+}
+
+/// A copy of the drawing's first sheet, as a sheet of its own.
+fn drawing_sheet_copy(d: &Drawing, id: u64) -> crate::drawing::Sheet {
+    crate::drawing::Sheet { id, name: "Sheet 2".into(), ..(*d.sheets[0]).clone() }
+}
+
+fn file(d: &Drawing) -> Value {
+    serde_json::from_str(&d.to_json().unwrap()).unwrap()
+}
+
+fn refused(d: &Drawing, edit: impl FnOnce(&mut Value)) -> String {
+    let mut v = file(d);
+    edit(&mut v);
+    Drawing::from_json(&v.to_string()).map_or_else(|e| e.to_string(), |_| "read".into())
+}
+
+#[test]
+fn an_image_is_saved_with_its_bytes_and_reads_back_the_same() {
+    let bytes = png(640, 480);
+    let (d, image, placed) = pictured(&bytes);
+    let saved = d.to_json().unwrap();
+    let read = Drawing::from_json(&saved).unwrap();
+    assert_eq!(read, d);
+    assert_eq!(read.to_json().unwrap(), saved);
+    let found = read.images.by_id(image).unwrap();
+    assert_eq!((found.format.as_str(), found.pixels), ("png", [640, 480]));
+    assert_eq!(base64_decode(&found.data).unwrap(), bytes);
+    assert_eq!(read.sheet_images.by_id(placed).map(|i| (i.rect_mm, i.image)), Some((RECT, image)));
+    assert!(read.images.by_id(placed).is_none() && read.sheet_images.by_id(image).is_none());
+}
+
+/// One file sits on two sheets and is saved once. Its bytes count once towards the caps, so a logo on
+/// every sheet costs what one does.
+#[test]
+fn one_file_on_two_sheets_is_saved_once() {
+    let mut logo = png(10, 10);
+    logo.resize(1 << 20, 0);
+    let (mut d, image, _) = pictured(&logo);
+    let first = d.sheets[0].id;
+    let mut id_source = IdSource::seeded(4);
+    let second = d.allocate_id(&mut id_source).unwrap();
+    let sheet = drawing_sheet_copy(&d, second);
+    d.sheets.push(Arc::new(sheet));
+    for n in 0..20u64 {
+        let id = d.allocate_id(&mut id_source).unwrap();
+        d.sheet_images.add([Arc::new(SheetImage { id, sheet: second, rect_mm: [n as f64, 0.0, n as f64 + 5.0, 5.0], image })]);
+    }
+    d.validate().unwrap();
+    assert_eq!((d.images.len(), d.sheet_images.len()), (1, 21));
+    let read = Drawing::from_json(&d.to_json().unwrap()).unwrap();
+    assert_eq!(read, d);
+    assert!(d.to_json().unwrap().len() < 2 << 20, "the bytes are there once");
+    assert_eq!(d.images_in_use(), BTreeSet::from([image]));
+
+    // The first sheet's going leaves the file for the second's, and the second's takes it.
+    d.remove_sheet(first);
+    assert_eq!((d.images.len(), d.sheet_images.len()), (1, 20));
+    d.validate().unwrap();
+    d.remove_sheet(second);
+    assert!(d.images.is_empty() && d.sheet_images.is_empty());
+}
+
+/// A file goes with its last placement, and nothing is left to save.
+#[test]
+fn a_file_goes_with_its_last_placement() {
+    let (mut d, _, placed) = pictured(&png(1, 1));
+    let (sheet, other) = (d.sheets[0].id, d.allocate_id(&mut IdSource::seeded(4)).unwrap());
+    let empty = drawing_sheet_copy(&d, other);
+    d.sheets.push(Arc::new(empty));
+    assert_eq!(d.on_sheet(sheet).images, [placed]);
+    assert!(!d.on_sheet(sheet).is_empty() && d.on_sheet(other).is_empty());
+    assert_eq!(d.remove_sheet(sheet).images, [placed]);
+    assert!(d.images.is_empty() && d.sheet_images.is_empty());
+    d.validate().unwrap();
+    let v = file(&d);
+    assert!(v.get("images").is_none() && v.get("sheet_images").is_none(), "{v}");
+    assert_eq!(Drawing::from_json(&v.to_string()).unwrap(), d, "an older drawing has neither");
+}
+
+#[test]
+fn ids_stay_apart_across_files_and_placements() {
+    let (d, image, placed) = pictured(&png(1, 1));
+    let taken = d.ids().collect::<BTreeSet<_>>();
+    assert!(taken.contains(&image) && taken.contains(&placed));
+    let mut twin = d.clone();
+    Arc::make_mut(&mut twin.sheet_images[0]).id = image;
+    assert!(twin.validate().is_err_and(|e| e.to_string().contains("two objects")));
+}
+
+#[test]
+fn the_caps_are_read_from_the_file_before_anything_decodes_it() {
+    let make = |b: &[u8]| ImageFile::from_file(1, b).map(|i| i.pixels).map_err(|e| e.to_string());
+    assert_eq!(make(&png(8_000, 8_000)), Ok([8_000, 8_000]));
+    assert_eq!(make(&jpeg(8_000, 8_000)), Ok([8_000, 8_000]));
+    // The limits, one over, and sizes whose product would overflow 32 bits.
+    for (w, h) in [(8_001, 8_000), (64_000_001, 1), (1, 64_000_001), (65_536, 65_536), (u32::MAX, u32::MAX)] {
+        assert!(make(&png(w, h)).is_err_and(|e| e.contains("pixels")), "{w} by {h}");
+    }
+    assert!(make(&jpeg(u16::MAX, u16::MAX)).is_err_and(|e| e.contains("pixels")));
+    let not_images: [&[u8]; 6] = [b"", b"GIF89a", b"\x89PNG", &png(0, 5), &png(5, 0), &jpeg(0, 5)];
+    for not_image in not_images {
+        assert!(make(not_image).is_err_and(|e| e.contains("PNG or JPEG")), "{not_image:?}");
+    }
+    let mut full = png(10, 10);
+    full.resize(MAX_IMAGE_BYTES, 0);
+    assert_eq!(make(&full), Ok([10, 10]));
+    full.push(0);
+    assert!(make(&full).is_err_and(|e| e.contains("MiB")));
+}
+
+#[test]
+fn a_file_that_lies_is_refused_on_reading() {
+    let (d, ..) = pictured(&png(10, 10));
+    let with = |key: &'static str, value: Value| move |v: &mut Value| v["images"][0][key] = value;
+    assert!(refused(&d, with("pixels", json!([1, 1]))).contains("disagree"));
+    assert!(refused(&d, with("format", "jpeg".into())).contains("disagree"));
+    assert!(refused(&d, with("format", "gif".into())).contains("PNG or a JPEG"));
+    assert!(refused(&d, with("data", "!!!".into())).contains("base64"));
+    assert!(refused(&d, with("data", base64_encode(&png(9_000, 9_000)).into())).contains("pixels"));
+    assert!(refused(&d, with("data", "".into())).contains("PNG or JPEG"));
+    assert!(refused(&d, with("pixels", json!([0, 10]))).contains("pixels"));
+    assert!(refused(&d, with("pixels", json!([65_536, 65_536]))).contains("pixels"));
+    assert!(refused(&d, with("path", "C:/secret.png".into())).contains("path"), "an unknown field is damage");
+}
+
+/// A placement names a file and a sheet the drawing has, and a file nothing places isn't kept.
+#[test]
+fn a_placement_and_its_file_name_each_other() {
+    let (d, ..) = pictured(&png(10, 10));
+    let placed = |key: &'static str, value: Value| move |v: &mut Value| v["sheet_images"][0][key] = value;
+    assert!(refused(&d, placed("sheet", ids::encode(1 << 41).into())).contains("sheet"));
+    assert!(refused(&d, placed("image", ids::encode(1 << 41).into())).contains("doesn't have"));
+    assert!(refused(&d, |v| v["sheet_images"] = json!([])).contains("nothing uses it"));
+    assert!(refused(&d, |v| v["images"] = json!([])).contains("doesn't have"));
+    assert!(refused(&d, placed("data", "AAAA".into())).contains("data"), "the file's bytes aren't the placement's");
+}
+
+#[test]
+fn a_rectangle_is_on_paper_and_has_a_size() {
+    let (d, ..) = pictured(&png(10, 10));
+    for rect in [
+        [60.0, 20.0, 10.0, 45.0],
+        [10.0, 45.0, 60.0, 20.0],
+        [10.0, 20.0, 10.0, 45.0],
+        [10.0, 20.0, 60.0, 20.0],
+        [1e300, 20.0, 2e300, 45.0],
+        [f64::NAN; 4],
+    ] {
+        let mut bad = d.clone();
+        Arc::make_mut(&mut bad.sheet_images[0]).rect_mm = rect;
+        assert!(bad.validate().is_err_and(|e| e.to_string().contains("rectangle")), "{rect:?}");
+    }
+}
+
+#[test]
+fn a_drawings_images_keep_their_counts() {
+    let (d, image, placed) = pictured(&png(1, 1));
+    // A file and something to use it, ids after the first ones.
+    let again = |d: &mut Drawing, n: u64, data: &str| {
+        let mut file = (*d.images[0]).clone();
+        file.id = image + 2 * n;
+        file.data = data.into();
+        let use_of = SheetImage { id: placed + 2 * n, sheet: d.sheets[0].id, rect_mm: RECT, image: file.id };
+        d.images.add([Arc::new(file)]);
+        d.sheet_images.add([Arc::new(use_of)]);
+    };
+    // One file's cap and the cap between them, checked on every edit from the text's length alone.
+    let mut big = d.clone();
+    Arc::make_mut(&mut big.images[0]).data = "A".repeat(encoded(MAX_IMAGE_BYTES) + 1);
+    assert!(big.validate().is_err_and(|e| e.to_string().contains("its file")));
+    let mut many = d.clone();
+    let full = "A".repeat(encoded(MAX_IMAGE_BYTES));
+    Arc::make_mut(&mut many.images[0]).data.clone_from(&full);
+    again(&mut many, 1, &full);
+    let room = encoded(MAX_IMAGES_BYTES) - 2 * full.len();
+    again(&mut many, 2, &"A".repeat(room));
+    many.validate().unwrap();
+    again(&mut many, 3, "A");
+    assert!(many.validate().is_err_and(|e| e.to_string().contains("between them")));
+    let mut crowd = d.clone();
+    (1..=MAX_IMAGES as u64).for_each(|n| again(&mut crowd, n, "AAAA"));
+    assert!(crowd.validate().is_err_and(|e| e.to_string().contains("at most")));
+    let mut placements = d.clone();
+    let logo = placements.sheet_images[0].clone();
+    let copies = (1..=MAX_SHEET_IMAGES as u64).map(|n| Arc::new(SheetImage { id: placed + 2 * n, ..(*logo).clone() }));
+    placements.sheet_images.add(copies.collect::<Vec<_>>());
+    assert!(placements.validate().is_err_and(|e| e.to_string().contains("at most")));
+    let mut twins = d.clone();
+    let twin = twins.sheet_images[0].clone();
+    twins.sheet_images.push(twin);
+    assert!(twins.validate().is_err());
+}

crates/doc/src/drawing/note.rs

@@ -0,0 +1,170 @@
+//! A drawing's notes (W19e, #4896): text on a sheet, in its fields and its words, that may point at
+//! the model with one leader.
+//!
+//! - **The anchor** says what a note belongs to: a sheet, a view, or an edge or a corner of a view's
+//!   model, saved by name as a dimension's is ([`super::dimension`]). It is one type so that other
+//!   symbols placed on a drawing can use it too.
+//! - **The place** is on paper: in millimetres from the sheet's lower-left corner for a note on a
+//!   sheet, and from the view's centre for any other, so that note moves with its view.
+//! - **The content** is the title block's text with fields ([`Content`]), so a sheet's number works
+//!   in a note. It reads what a note can name: never an answer given when a block was placed, or a
+//!   table's row.
+//! - **The leader** is worked out, never saved, from where the anchor stands with the model now
+//!   ([`Document::resolve_notes`]). A lost reference keeps the note and its text where they are,
+//!   without a leader.
+//!
+//! The rules, beside the record's: its sheet or view is one of the drawing's; an edge or a corner
+//! keeps a dimension's reference rules; its place is on paper ([`is_paper_coordinate`]); its text
+//! height is [`CAP_MM`]; at most [`MAX_NOTES`] notes, listed by id.
+
+use std::ops::RangeInclusive;
+
+use serde::{Deserialize, Serialize};
+use solidcore_record::Vec3;
+use solidcraft_geom::cell::{Content, Part, Source};
+use solidcraft_geom::drawing_view::is_paper_coordinate;
+use solidcraft_geom::paper::MAX_SIDE_MM;
+
+use super::by_id::Record;
+use super::dimension::{Lookup, ModelEdge, ModelPoint, Status, check_edge, check_point};
+use super::{Drawing, require};
+use crate::{DocError, Document, Model, Result, ids};
+
+/// The most notes a drawing may have.
+pub const MAX_NOTES: usize = 10_000;
+/// The text heights a note may set, in millimetres of paper.
+pub const CAP_MM: RangeInclusive<f64> = 0.5..=100.0;
+
+/// What a note belongs to.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case", deny_unknown_fields)]
+pub enum Anchor {
+    /// A sheet, by its id.
+    Sheet(#[serde(with = "crate::ids")] u64),
+    /// A view, by its id.
+    View(#[serde(with = "crate::ids")] u64),
+    /// An edge of a view's model: its leader ends on the edge's middle.
+    Edge {
+        #[serde(with = "crate::ids")]
+        view: u64,
+        edge: ModelEdge,
+    },
+    /// A corner or a centre of a view's model: its leader ends there.
+    Corner {
+        #[serde(with = "crate::ids")]
+        view: u64,
+        point: ModelPoint,
+    },
+}
+
+impl Anchor {
+    /// The view it moves with, if any.
+    pub fn view(&self) -> Option<u64> {
+        match self {
+            Anchor::Sheet(_) => None,
+            Anchor::View(view) | Anchor::Edge { view, .. } | Anchor::Corner { view, .. } => Some(*view),
+        }
+    }
+
+    /// The same anchor on view `view`, when it is on one.
+    pub fn on_view(&self, view: u64) -> Anchor {
+        let mut anchor = self.clone();
+        if let Anchor::View(on) | Anchor::Edge { view: on, .. } | Anchor::Corner { view: on, .. } = &mut anchor {
+            *on = view;
+        }
+        anchor
+    }
+}
+
+/// One note of a drawing.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct Note {
+    #[serde(with = "crate::ids")]
+    pub id: u64,
+    pub anchor: Anchor,
+    /// Where it sits, in millimetres of paper from its sheet's corner, or from its view's centre.
+    pub at: [f64; 2],
+    pub content: Content,
+    /// The height of its capitals on paper, when it sets its own.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub cap_mm: Option<f64>,
+}
+
+impl Record for Note {
+    fn id(&self) -> u64 {
+        self.id
+    }
+}
+
+impl Drawing {
+    /// The notes' rules (the module's notes). The views are checked first, so they are in id order
+    /// here.
+    pub(super) fn check_notes(&self) -> Result<()> {
+        self.notes.check(MAX_NOTES, "note", |n| self.check_note(n))
+    }
+
+    fn check_note(&self, n: &Note) -> Result<()> {
+        match &n.anchor {
+            Anchor::Sheet(sheet) => {
+                require(self.sheets.iter().any(|s| s.id == *sheet), || {
+                    format!("it is on sheet {}, which the drawing doesn't have", ids::encode(*sheet))
+                })?;
+            }
+            Anchor::View(_) => {}
+            Anchor::Edge { edge, .. } => check_edge(edge)?,
+            Anchor::Corner { point, .. } => check_point(point)?,
+        }
+        if let Some(view) = n.anchor.view() {
+            require(self.view(view).is_some(), || format!("it is on view {}, which the drawing doesn't have", ids::encode(view)))?;
+        }
+        require(!n.content.0.is_empty(), || "it has some text".into())?;
+        n.content.validate().map_err(|e| DocError::Invalid(e.0.into()))?;
+        let can_read = |part: &Part| !matches!(part, Part::Field { source: Source::Prompt | Source::Row, .. });
+        require(n.content.0.iter().all(can_read), || "its fields read the drawing, its sheet, its component or its newest revision".into())?;
+        let [x, y] = n.at;
+        require(is_paper_coordinate(x) && is_paper_coordinate(y), || format!("its place is at most {MAX_SIDE_MM} mm on paper"))?;
+        require(n.cap_mm.is_none_or(|cap| CAP_MM.contains(&cap)), || format!("its text height is {} to {} mm", CAP_MM.start(), CAP_MM.end()))
+    }
+}
+
+/// A note as the model has it now ([`Document::resolve_notes`]): never saved.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Resolved {
+    /// Always [`Status::Ok`] for a note on a sheet or a view, which reads no model.
+    pub status: Status,
+    /// Where its leader ends, in the design's frame: when it has one.
+    pub point: Option<Vec3>,
+    /// What it points at was found by exact history, as one edge.
+    pub exact: bool,
+}
+
+impl Document {
+    /// The notes `wanted` of `drawing` (one of this design's drawings) as `model` (this design's) has
+    /// them now, as [`Document::resolve_balloons`] finds balloons'. `Err` only for an id the drawing
+    /// doesn't have.
+    pub fn resolve_notes(&self, model: &Model, drawing: &Drawing, wanted: &[u64]) -> Result<Vec<Resolved>> {
+        let mut lookup = Lookup::new(self, model);
+        wanted
+            .iter()
+            .map(|id| {
+                let n = drawing.notes.by_id(*id).ok_or_else(|| DocError::Unknown(format!("note {}", ids::encode(*id))))?;
+                Ok(match &n.anchor {
+                    Anchor::Sheet(_) | Anchor::View(_) => Resolved { status: Status::Ok, point: None, exact: true },
+                    Anchor::Edge { edge, .. } => {
+                        let (status, point, exact) = lookup.middle(edge);
+                        Resolved { status, point, exact }
+                    }
+                    Anchor::Corner { point, .. } => match lookup.corner(point) {
+                        Ok((at, exact)) => Resolved { status: Status::Ok, point: Some(at), exact },
+                        Err(status) => Resolved { status, point: None, exact: false },
+                    },
+                })
+            })
+            .collect()
+    }
+}
+
+#[cfg(test)]
+#[path = "note_tests.rs"]
+mod tests;