Each of these asks the allocator for tens of gigabytes, or runs for hours, from
a file of a few kilobytes to a few megabytes. An allocation failure is an abort,
so no panic guard can report it and the user's unsaved work is gone.
- IGES composite curves (102) name their children by pointer, and a tree whose
every node names the same child twice fans out to 2^30 leaf visits under the
depth cap. Count the entities visited and the segments produced against one
budget, since a node that yields no segment trips no bound on the output, and
refuse a composite curve that contains itself.
- IGES directory entries could all name the same parameter range, each
materialising it as its own string and token list. Keep the total text
proportional to the parameter section the file carries.
- STEP knot multiplicities were expanded into one value each before the knot
count was compared with the control points: 20 million knots of multiplicity
64 built a 10 GB vector only to be rejected. Check the sum first.
- One STEP face could list any number of boundary loops, each cloning its edge
handles into a new wire that the face extent then samples. Cap the loops and
the edges they hold; 100,000 bounds went from 2.1 GB to an immediate error.
Also guard the IGES translation, which was the one importer stage outside every
panic guard, keep the vertex-sewing bucket key clear of the overflow its
neighbour lookup caused for coordinates near f64's range, and count how often a
loop passes each vertex once instead of once per edge.
Fixes#146
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
(cherry picked from commit c32792b71c76d74348ad5002d8d2da870937e58e)
- 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
bherbruck