- IGES import (kernel iges_in, from the published specification). The file
is restated as STEP and read by the STEP reader, so an IGES file becomes
the same Import base feature.
- Manifold solid B-reps (186/514/510/508/504/502).
- Trimmed (144), bounded (143) and bare B-spline surfaces, sewn into a
solid by shared edges, with face orientation made consistent.
- Curves: lines, arcs, ellipses, composite and rational B-spline curves.
- Surfaces: planes, analytic surfaces 190-198, B-spline surfaces,
surfaces of revolution and tabulated cylinders.
- Transformations, units, colours, names (406 form 15 or labels).
Open, insert and drop .igs/.iges like STEP.
- IGES export (kernel iges_out): each body as a manifold solid B-rep on the
surfaces a STEP export uses, with name properties and colours.
ExportCommand to .igs.
- OBJ import as mesh bodies: objects/groups, polygons fanned, negative
indices, bad lines reported.
- STL: binary files whose header starts with "solid" and those with a zero
triangle count read as binary; non-finite vertices dropped; facet
normals ignored; ASCII with non-UTF-8 names. Mesh bodies get consistent
winding (stray inverted facets turned over).
- Tests: primitives and features round-trip through IGES (volume, area,
name, colour). Six trimmed patches sew into a closed box. Hostile IGES,
OBJ and STL inputs never panic. STL quirks. The engine exports a design
to IGES and opens it again. All 76 oracle parts round-trip through IGES
with matching volume (local check).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
