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Petru Conduraru
de40b5f685
PR #8503 (already open on this branch) added an edge parity check to util.shape.get_volume: every undirected edge of a triangulated mesh must be shared by exactly two triangles, otherwise the divergence theorem sum is meaningless and nan is returned instead of a wrong number. That check matches Moult's "edge face connectivity" suggestion in the issue thread and is verified to turn the reported slabs' volume from 17.71 m3 (against a 1.82 m3 bounding box) into nan. It only implements half of aothms' actual suggestion though. He asked for two checks: unoriented edges used exactly twice, and oriented (directed) edges used at most once. The existing check only does the first. A mesh can pass an unordered edge count check while still having two triangles that share an edge with the same winding direction instead of opposite ones (for example one flipped normal on an otherwise closed shape). That is a real non-manifold defect that silently corrupts the volume sum instead of producing an error: a unit cube with one triangle's winding flipped in place still passes the count == 2 check per edge, but get_volume returns 0.667 instead of 1.0. is_manifold now also tracks directed edge usage and requires it to be exactly one, catching this case and returning nan for it too, verified against both the flipped cube and the original reported slabs. Separately, the issue reports the volume is "wildly off via ifcopenshell and blender", but PR #8503 only touches the ifcopenshell.util.shape path used by the IfcOpenShell qto calculator. Bonsai's own Blender qto calculator (bonsai.bim.module.qto.calculator) computes volumes with bmesh.calc_volume() on the live mesh, which has the identical divergence theorem assumption and the identical bug, entirely unguarded. Verified live in headless Blender: an open cube (one face deleted) reports 6.667 instead of erroring, and a cube with one face's winding flipped reports 5.333. get_net_volume and get_gross_volume now check bmesh edge.is_contiguous (manifold and matching winding) and return None instead, which the existing qto pipeline already treats as "skip this quantity". The dependent get_space_net_volume, get_gross_weight and get_net_weight functions are updated to propagate None instead of computing arithmetic on it. Verified with the reporter's attached slabs-only.ifc (three non-manifold IfcPolygonalFaceSet slabs): get_volume returns nan for all three through the real ifc5d.qto.quantify() dispatch, so no Volume quantity is written, matching Bruno's request to skip volume calculation for non-manifold tessellations entirely. Regression checked with a closed manifold cube through both calculators (unchanged, correct volume). Added unit tests for is_manifold/get_volume (util/shape.py) covering closed, open and inconsistent winding meshes, and a Bonsai qto regression test building a non-manifold wall mesh and asserting its Volume quantities are omitted rather than wrong. Black and ruff pass on all touched files. Generated with the assistance of an AI coding tool.
IfcOpenShell
IfcOpenShell is an open source (LGPL) software library for working with Industry Foundation Classes (IFC). Complete parsing support is provided for IFC2x3 TC1, IFC4 Add2 TC1, IFC4x1, IFC4x2, and IFC4x3 Add2. Extensive geometric support is implemented for the IFC releases IFC2x3 TC1 and IFC4 Add2 TC1. Extending with support for arbitrary IFC schemas is possible at compile-time when using C++ and at run-time when using Python.
In addition to a C++ and Python API, IfcOpenShell comes with an ecosystem of tools, notably including IfcConvert (an application to convert IFC models to other formats), Bonsai (an add-on to Blender providing a graphical IFC authoring platform), and many other libraries, CLI apps, and more. Support is also provided for auxiliary standards such as BCF and IDS.
For more information, see:
Development is sponsored through your generous donations!
Contents
| Name | Description | License | Service |
|---|---|---|---|
| bcf | Library to read and write BCF-XML and query OpenCDE BCF-API modules | LGPL-3.0-or-later |   |
| bonsai | Add-on to Blender providing a graphical native IFC authoring platform | GPL-3.0-or-later |    |
| bsdd | Library to query the bSDD API | LGPL-3.0-or-later |  |
| ifc2ca | Utility to convert IFC structural analysis models to Code_Aster | LGPL-3.0-or-later | |
| ifc4d | Convert to and from IFC and project management software | LGPL-3.0-or-later |  |
| ifc5d | Report and optimise cost information from IFC | LGPL-3.0-or-later |  |
| ifcbimtester | Wrapper for Gherkin based unit testing for IFC models | LGPL-3.0-or-later | |
| ifcblender | Historic Blender IFC import add-on | LGPL-3.0-or-later* | |
| ifccityjson | Convert CityJSON to IFC | LGPL-3.0-or-later |  |
| ifcclash | Clash detection library and CLI app | LGPL-3.0-or-later |  |
| ifcconvert | CLI app to convert IFC to many other formats | LGPL-3.0-or-later* |   |
| ifccsv | Library and CLI app to export and import schedules from IFC | LGPL-3.0-or-later |  |
| ifcdiff | Compare changes between IFC models | LGPL-3.0-or-later |  |
| ifcedit | CLI wrapper for ifcopenshell.api IFC model mutation functions | LGPL-3.0-or-later |  |
| ifcfm | Extract IFC data for FM handover requirements | LGPL-3.0-or-later |  |
| ifcmax | Historic extension for IFC support in 3DS Max | LGPL-3.0-or-later* | |
| ifcmcp | MCP server for querying and editing IFC building models | LGPL-3.0-or-later |  |
| ifcopenshell-python | Python library for IFC manipulation | LGPL-3.0-or-later* |         |
| ifcpatch | Utility to run pre-packaged scripts to manipulate IFCs | LGPL-3.0-or-later |  |
| ifcquery | CLI tool for querying and inspecting IFC building models | LGPL-3.0-or-later |  |
| ifcsverchok | Blender Add-on for visual node programming with IFC | GPL-3.0-or-later |  |
| ifctester | Library, CLI and webapp for IDS model auditing | LGPL-3.0-or-later |  |
The IfcOpenShell C++ codebase is split into multiple interal libraries:
| Name | Description | License |
|---|---|---|
| ifcgeom | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcgeom_schema_agnostic | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcgeomserver | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcjni | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcparse | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcwrap | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| qtviewer | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| serializers | Internal library for IfcOpenShell | LGPL-3.0-or-later* |