create_shape() returns a Python-owned Element (SWIG_POINTER_OWN in the
boost::variant out typemap). Its .geometry property calls Element::geometry(),
which returns a reference into the element's boost::shared_ptr<Representation>
_geometry member. SWIG wraps that reference as a non-owning pointer, so the
returned Triangulation/BRep/Serialization proxy does not keep the element alive.
When a caller keeps only .geometry (e.g. create_shape(s, e).geometry) and drops
the parent element, Python garbage-collects the element, destroying its
shared_ptr and freeing the underlying representation. Subsequent reads of
verts/faces then return freed memory: empty or implausible float/int garbage,
non-deterministically depending on GC and allocator timing. This is silent data
corruption, not a crash, and has bitten users since 2020.
Fix: in the TriangulationElement/SerializedElement/BRepElement pythoncode, wrap
the geometry getter so the returned geometry stores a backreference to its
owning element (result._parent = self). This makes the parent's lifetime at
least as long as the geometry's, automatically and transparently, so no caller
has to remember to hold the element. This is aothms's suggested backreference,
applied generically in the binding rather than left as a workaround.
Reproduced deterministically (washBasin fixture): before, verts len 0 vs 133500
across repeated GC-pressure runs; after, 133500 every run for all three element
types. test_create_shape passes; no regressions.
Note: tree.select_ray()'s ray_intersection_result (2024 follow-up in #1124) is a
separate ownership mechanism (std::vector element reference + std::array member
pointer) and is left as follow-up scope.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Add svg-use-edge-classification (default off, preserving today's
linework), svg-render-crease-edges, and svg-render-sharp-edges
settings, gating the existing 5-class classification feature so it
can be disabled entirely (falling back to the pre-classification
whole-shape output) or have individual classes suppressed.
Also fixes a bug uncovered while wiring this into Bonsai: ready(),
where geometry_settings() actually gets read into the serializer,
was only ever invoked explicitly by IfcConvert's CLI driver and
isn't exposed to Python. Every Svg* setting -- including the three
from previous rounds -- silently stayed at its hardcoded constructor
default when the serializer was constructed directly through the
Python bindings, as Bonsai does. Fixed by calling ready() from
SvgSerializer's own constructor, safe since it only reads
geometry_settings() with no other side effects, and settings are
always finalized before construction in every call path.
Generated with the assistance of an AI coding tool.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
- `function_item`, `tags` added in df7318973
- MakeVolume added in c385b93, ignore as all other conversion settings
- moved `SeparateZUpNode` ignore to the other geom serializer settings
Petru Conduraru