* claim: #3353
* Sheet metal: mirrored and copied sheet bodies stay sheet metal
Mirroring a sheet metal body into a new body gave a plain solid: the
opposite-hand bracket had no flat pattern, DXF or bend table
("`Body1 (2)` is not a sheet metal body"). Copies from a body pattern or
Move with copy lost their sheet model the same way.
A copy now takes the sheet model with it (SheetBody::copied). A rigid
copy moves the flat frame. A mirror moves the frame with its x axis
turned round, so the thickness side stays, and mirrors everything in
flat coordinates (x -> -x): base, flange bend lines (run from their far
end, with their end extensions, slopes and tears swapped), panel shapes,
cut-outs, pockets, bores, letters and base sketch lines. Arcs stay exact
and loops keep their sense. A perforation field of a mirrored copy runs
its grid from the right, so its holes are the mirror image too. The flat
length, bends and K-factor are unchanged, and the copy takes further
sheet metal features of its own.
Mirror with combine is unchanged: the joined body has no single sheet
model yet. Mirroring or patterning flange features is still refused.
Sheet models are derived from the timeline, so no design format change.
* Format: note the saved from_right of a mirrored sheet's perforation field
The new `from_right` flag is saved in the design, so it gets a pending
format note. No migration: a field without it runs from the left as
before.
raykholo
d9d6af51c6