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Petru Conduraru
86de6c27d6
Issue #6895 reported get_shape_bottom_elevation returning huge identical garbage (-2e100) on an IFC4X1 file, while the same query worked fine on IFC2X3. Reproduced live with the reporter's file: all 444 IfcWindow elements return -2e100. Investigated the offending representations directly: each window's "Body" IfcShapeRepresentation is declared RepresentationType SweptSolid, but its actual Items are IfcTriangulatedFaceSet entities (which belong under Tessellation, not SweptSolid) plus an IfcGeometricSet containing thousands of untrimmed IfcLine entities used directly as body geometry items. An untrimmed IfcLine is an unbounded curve, invalid as a body representation item; the backing geometry kernel tessellates it using a "practical infinity" coordinate (around 1e100, matching OpenCASCADE's Precision::Infinite()) rather than a true float infinity, which is what get_shape_bottom_elevation's naive min() picks up. All 444 windows share this pattern, and the file uses no representation identifier other than Body/SweptSolid anywhere, pointing to a systemic bug in the authoring tool named in the file header rather than anything IFC4X1 specific. Confirmed schema is incidental: re-declaring the same file's header as plain IFC4 and re-running reproduces the identical -2e100 result, and a minimal synthetic model with a single untrimmed IfcLine item reproduces it on a from-scratch, otherwise well-formed IFC4 file. So the file genuinely is invalid, but returning -2e100 silently with no signal is also a real, separate robustness gap: any malformed body representation with an unbounded curve item now produces a nonsensical "valid-looking" number instead of an obvious error. This adds a guard to get_bottom_elevation/get_top_elevation and their get_shape_*/ get_element_* variants: any vertex Z ordinate that is non-finite or at the kernel's "practical infinity" magnitude now makes the function warn and return NaN instead of folding the sentinel into the result. This does not attempt to "correct" the geometry or compute an elevation from the remaining finite vertices; it only turns silent garbage-in into a loud, unambiguous failure signal, while leaving valid geometry (including geometry with legitimately large but finite coordinates) untouched. Verified live: the reporter's file now returns NaN with a warning for every window instead of -2e100. A valid extruded wall (bottom=0, top=3) is unaffected and emits no warning. Added test/util/test_shape.py, which did not previously exist for this module; both new tests pass against the fix and the degenerate case correctly fails against unpatched code. Ran the existing test/util/ suite before and after: same 6 pre-existing, unrelated environment failures (missing mathutils, one broken validate-stub fixture) in both runs, no new failures. Related to #6895 This commit was created 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* |