In _extract_mesh(), BRep_Tool.Triangulation_s(face, face_loc) returns a face_loc
that already encodes the instance's full placement transform when a compound shape
is tessellated with BRepMesh_IncrementalMesh. Applying shape_trsf on top doubled
every rotation/translation, causing multiple roller elements to collapse to the same
wrong world position (e.g. Z(-75°)×2 ≡ Z(+105°)×2 mod 360° → identical positions).
Fix: use elif so shape_loc is only applied as a fallback when face_loc is identity.
Adds seam edge extraction (UV seam primvar) and improves _traverse_xcaf doc.
docs: learning erfasst - OCC face_loc double-transform in compound tessellation
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Hartmut
de7f97be87