Boolean Operations generating invalid meshes #549
Description
Description
I’m trying to load the attached IFC model. In these models, I isolated the problematic geometries: they are all walls generated by Boolean Operations
This is the correct mesh:
When I load the file using the master branch (v5.1.820), I get invalid meshes – only a few triangles are generated. The issue seems to come from the following line in Xbim3DModelContext.cs:
// Line 929
nextGeom = elementGeom.Cut(openingAndProjectionOp.CutGeometries, precision);
Mesh generated by xbim:
For the full model (to which these walls belong), generating some walls gradually allocates more and more memory until the process eventually crashes.
I think it's some bug or inaccuracy in OCC, but this issue seems to have been resolved in version 6, in the feature/netcore branch.
Precision behavior
- Changing the precision gives mixed results: one wall may succeed, while another one fails.
- precision = 0.000001 seems to produce correct geometries for these walls.
- However, the same precision causes uncut geometries in other IFC files created with the same modeling software.
Branch comparison
- On the master branch (v5.1.820) → meshes are invalid.
- On the feature/netcore branch → walls are generated correctly.
Is it possible to run version 5.1.820 with the latest OCC release, or are there any known fixes available for 5.1.820?
Ifc models:
https://drive.google.com/drive/folders/1TkmLu1imDf5GRjpeh-vNjB1z0NHaQZMM?usp=sharing
Correct mesh generated by the feature/netcore branch version:
