diff --git a/crates/ui-egui/src/agent_chat/tests.rs b/crates/ui-egui/src/agent_chat/tests.rs
index 05564e2d6a..958d890b05 100644
--- a/crates/ui-egui/src/agent_chat/tests.rs
+++ b/crates/ui-egui/src/agent_chat/tests.rs
@@ -2293,12 +2293,17 @@ fn the_picks_go_with_the_next_message_once() {
 }
 
 /// Two clicks on two rims are two things, not four edges (a click on a rim selects both halves for
-/// the commands; the chat counts and describes what was clicked).
+/// the commands; the chat counts and describes what was clicked). The cylinder is a circle drawn
+/// as two half arcs, extruded, so each rim is in two halves.
 #[test]
 fn a_rim_clicked_once_is_one_item_not_its_pieces() {
     use solidcraft_engine::Sel;
     let (mut app, script, ctx) = app_with_script();
-    app.run("solid.cylinder", json!({"radius": 10, "height": 20})).expect("a cylinder");
+    app.run("sketch.create", json!({"plane": "XY"})).expect("a sketch");
+    app.run("sketch.arc.three_point", json!({"start": [10, 0], "end": [-10, 0], "through": [0, 10]})).expect("an arc");
+    app.run("sketch.arc.three_point", json!({"start": [-10, 0], "end": [10, 0], "through": [0, -10]})).expect("an arc");
+    app.run("sketch.finish", json!({})).expect("the sketch");
+    app.run("solid.extrude", json!({"distance": 20})).expect("a cylinder");
     let (name, top, bottom, mid_top, mid_bottom) = {
         let st = crate::open_meshing::session_world(&app.session);
         let body = &st.bodies[0];
diff --git a/crates/ui-egui/src/dialogs_motion.rs b/crates/ui-egui/src/dialogs_motion.rs
index 47f697b426..10b7d15682 100644
--- a/crates/ui-egui/src/dialogs_motion.rs
+++ b/crates/ui-egui/src/dialogs_motion.rs
@@ -1103,10 +1103,11 @@ mod tests {
         assert!(matches!(&target.certificate, Some(solidcraft_engine::doc::config::FaceCertificate::ExtrudeSide { curve, .. }) if curve == "outer"));
         let state = h.app.session.model.state();
         let body = state.body("Ring").unwrap();
+        // The outer circle, one closed curve, is one wall face.
         let indices = h.app.session.doc.configuration_face_indices(body, target).unwrap();
-        assert_eq!(indices.len(), 2);
+        assert_eq!(indices.len(), 1);
         let painted = h.app.session.doc.face_colors(body);
-        assert_eq!(painted.len(), 2);
+        assert_eq!(painted.len(), 1);
         assert!(painted.iter().all(|(index, _)| indices.contains(index)));
     }
 
diff --git a/crates/ui-egui/src/viewport.rs b/crates/ui-egui/src/viewport.rs
index 04acbc8674..4a59d6adf8 100644
--- a/crates/ui-egui/src/viewport.rs
+++ b/crates/ui-egui/src/viewport.rs
@@ -8304,6 +8304,21 @@ mod tests {
         app
     }
 
+    /// A Ø20 × 20 cylinder whose wall and rims are each in two halves: a circle drawn as two
+    /// half arcs, extruded (one wall face per arc). SMLib's own cylinder has one wall and one
+    /// edge per rim; a rim or wall in pieces comes from a profile like this one or an import.
+    fn split_cylinder_app() -> SolveApp {
+        let mut s = solidcraft_engine::Session::default();
+        s.execute("sketch.create", &json!({"plane": "XY"})).unwrap();
+        s.execute("sketch.arc.three_point", &json!({"start": [10, 0], "end": [-10, 0], "through": [0, 10]})).unwrap();
+        s.execute("sketch.arc.three_point", &json!({"start": [-10, 0], "end": [10, 0], "through": [0, -10]})).unwrap();
+        s.execute("sketch.finish", &json!({})).unwrap();
+        s.execute("solid.extrude", &json!({"distance": 20})).unwrap();
+        let mut app = SolveApp::new(s, crate::Services::default());
+        app.set_origin_shown(false);
+        app
+    }
+
     /// Moving the pointer across a face keeps its highlight (a scanned mesh is one face of
     /// millions of triangles): only another face, edge or plane builds it again.
     #[test]
@@ -8642,9 +8657,13 @@ mod tests {
                 })
             })
             .unwrap();
-        assert!(mesh.seams[crease], "the fixture must exercise the coarse seam false positive");
+        // Truck's coarse seam fit took this crease for a seam between pieces of one surface;
+        // the seam flags now compare the exact surfaces (`topo::seam_flags`). Either way the
+        // certified crease is sharp, drawn in wireframe and picked. Its kink of a millionth is
+        // too close to tangent to show in the shading (`smooth_edges::Join`: smooth and a
+        // measured crease at once), so the shaded view leaves it out.
         assert!(mesh.sharp_edges[crease]);
-        assert!(mesh.shaded_edge_visible(crease));
+        assert!(mesh.edge_visible(crease) && !mesh.shaded_edge_visible(crease));
         assert!(mesh.edge_pickable(crease));
         assert!(mesh.edge_faces[crease].iter().any(|f| mesh.surface_patch(*f as usize).len() == 1));
         let mid = polyline_mid(&mesh.edges[crease]);
@@ -8660,7 +8679,7 @@ mod tests {
 
     #[test]
     fn circular_items_measure_as_whole_rims_and_surfaces() {
-        let mut app = cylinder_app();
+        let mut app = split_cylinder_app();
         let st = app.session.world_state().unwrap();
         let b = &st.bodies[0];
         let m = b.mesh();
@@ -8741,7 +8760,7 @@ mod tests {
 
     #[test]
     fn circular_rim_hover_click_and_dialog_pick_include_both_halves() {
-        let mut app = cylinder_app();
+        let mut app = split_cylinder_app();
         let st = app.session.world_state().unwrap();
         let b = &st.bodies[0];
         let m = b.mesh();
@@ -8788,7 +8807,7 @@ mod tests {
 
     #[test]
     fn curved_face_hover_selection_and_dialogs_cross_the_seam() {
-        let mut app = cylinder_app();
+        let mut app = split_cylinder_app();
         let st = app.session.world_state().unwrap();
         let b = &st.bodies[0];
         let m = b.mesh();