ifcpatch Migrate: defensive IFC4/IFC4X3 -> IFC2X3 downgrade

The Migrate recipe previously crashed mid-loop with the cryptic `RuntimeError: Entity with name '' not found in schema 'IFC2X3'` when asked to downgrade an IFC4 or IFC4X3 file to IFC2X3 — the class_4_to_2x3 mapping marks IFC4-only geometry / element classes with an empty-string sentinel and the old code blindly forwarded that to create_entity. Real files routinely contain IfcPolygonalFaceSet, IfcTriangulatedFaceSet, IfcIndexedPolyCurve, IfcLamp, IfcPipeSegment, IfcGeographicElement, etc. The recipe now runs a preprocessing pipeline when the target is IFC2X3 and the source is IFC4 or IFC4X3: - DowngradeIndexedPolyCurve flattens IfcIndexedPolyCurve to IfcPolyline for the whole file (arcs included — see below). - IfcPolygonalFaceSet / IfcTriangulatedFaceSet are converted directly to IfcFacetedBrep at the entity level via ifcopenshell.util.shape_builder.polygonal_face_set_to_faceted_brep, preserving topology including IfcIndexedPolygonalFaceWithVoids inner bounds. IfcShapeRepresentation carriers have their RepresentationType tag updated from "Tessellation" to "Brep". - Orphan source-only geometry instances (left over after the rewires) are purged iteratively via geometry_classes_introduced_after(target, source). The Migrator is invoked with fallback_element_to_proxy=True so IFC4-only IfcElement subclasses (IfcLamp, IfcPipeSegment, IfcGeographicElement, ...) become IfcBuildingElementProxy in the output. A post-pass encodes "<OriginalClass>/<PredefinedType>" into ObjectType (e.g. "IfcLamp/COMPACTFLUORESCENT") when ObjectType is empty, so the lost subclass identity survives the downgrade as searchable text. The migration loop now collects per-entity failures into a list rather than crashing on the first; a summary RuntimeError fires at end if any failed, naming up to 20 with their inverse references. Successful migrations log a single count line via self.logger. DowngradeIndexedPolyCurve extended: - Arc segments (IfcArcIndex) are flattened via ifcopenshell.util.shape_builder.arc_to_polyline_points with ARC_SUBDIVISION=16 chord points per arc. - Multi-index IfcLineIndex segments handled correctly. - Absent Segments list (IFC4 polyline-through-all-coords case) handled. Test coverage: 11 tests across the two recipes covering all four preprocessing branches, the IFC4X3 source gate, the ObjectType encoding (incl. author-supplied ObjectType preservation), the summary RuntimeError shape, and the arc subdivision. Generated with the assistance of an AI coding tool.
2026-09-22 13:58:12 +00:00 · 2026-06-23 09:33:03 +02:00
parent a2dafc9ceb
commit f710929e9e
4 changed files with 499 additions and 19 deletions
@@ -0,0 +1,137 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2026 Bonsai Contributors
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+import ifcpatch
+import test.bootstrap
+
+
+class TestDowngradeIndexedPolyCurve(test.bootstrap.IFC4):
+    def _make_curve(self, segments=None):
+        point_list = self.file.create_entity(
+            "IfcCartesianPointList2D",
+            CoordList=[(0.0, 0.0), (1.0, 0.0), (1.0, 1.0)],
+        )
+        curve = self.file.create_entity(
+            "IfcIndexedPolyCurve",
+            Points=point_list,
+            Segments=segments,
+        )
+        self.file.create_entity(
+            "IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve
+        )
+        return curve
+
+    def test_run_without_segments(self):
+        """An IfcIndexedPolyCurve with no Segments must downgrade to an
+        IfcPolyline through every CoordList point in order — IFC4 defines
+        the implicit-polyline meaning of an absent Segments list, and the
+        ifcopenshell shape builder emits this form for simple open curves."""
+        self._make_curve(segments=None)
+        ifcpatch.execute(
+            {"input": "input.ifc", "file": self.file, "recipe": "DowngradeIndexedPolyCurve", "arguments": []}
+        )
+        polylines = self.file.by_type("IfcPolyline")
+        assert len(polylines) == 1
+        assert len(polylines[0].Points) == 3
+
+    def test_run_with_line_segments(self):
+        """Line-segmented IfcIndexedPolyCurves downgrade to an equivalent IfcPolyline."""
+        segments = [
+            self.file.createIfcLineIndex((1, 2)),
+            self.file.createIfcLineIndex((2, 3)),
+        ]
+        self._make_curve(segments=segments)
+        ifcpatch.execute(
+            {"input": "input.ifc", "file": self.file, "recipe": "DowngradeIndexedPolyCurve", "arguments": []}
+        )
+        polylines = self.file.by_type("IfcPolyline")
+        assert len(polylines) == 1
+        assert len(polylines[0].Points) == 3
+
+    def test_run_with_multi_index_line_segment(self):
+        """An IfcLineIndex with >2 indices encodes a polyline through every
+        index — the downgraded IfcPolyline must include every one of them.
+        This is the canonical form Bonsai's shape builder emits for closed
+        rectangle profiles (e.g. parametric wall body outlines), serialised
+        as ``IfcIndexedPolyCurve(Points, (IfcLineIndex((1,2,3,4,1))))``."""
+        point_list = self.file.create_entity(
+            "IfcCartesianPointList2D",
+            CoordList=[(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)],
+        )
+        curve = self.file.create_entity(
+            "IfcIndexedPolyCurve",
+            Points=point_list,
+            Segments=[self.file.createIfcLineIndex((1, 2, 3, 4, 1))],
+        )
+        self.file.create_entity(
+            "IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve
+        )
+        ifcpatch.execute(
+            {"input": "input.ifc", "file": self.file, "recipe": "DowngradeIndexedPolyCurve", "arguments": []}
+        )
+        polylines = self.file.by_type("IfcPolyline")
+        assert len(polylines) == 1
+        assert len(polylines[0].Points) == 5
+        coords = [p.Coordinates for p in polylines[0].Points]
+        assert coords[0] == coords[-1] == (0.0, 0.0)
+        assert coords[1] == (1.0, 0.0)
+        assert coords[2] == (1.0, 1.0)
+        assert coords[3] == (0.0, 1.0)
+
+    def test_run_with_chained_multi_index_segments(self):
+        """When two IfcLineIndex segments are chained, the shared endpoint
+        between them must appear once, not twice."""
+        point_list = self.file.create_entity(
+            "IfcCartesianPointList2D",
+            CoordList=[(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)],
+        )
+        curve = self.file.create_entity(
+            "IfcIndexedPolyCurve",
+            Points=point_list,
+            Segments=[
+                self.file.createIfcLineIndex((1, 2, 3)),
+                self.file.createIfcLineIndex((3, 4)),
+            ],
+        )
+        self.file.create_entity(
+            "IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve
+        )
+        ifcpatch.execute(
+            {"input": "input.ifc", "file": self.file, "recipe": "DowngradeIndexedPolyCurve", "arguments": []}
+        )
+        polylines = self.file.by_type("IfcPolyline")
+        assert len(polylines) == 1
+        coords = [p.Coordinates for p in polylines[0].Points]
+        assert coords == [(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)]
+
+    def test_run_facets_arc_segments(self):
+        """Arc-segmented IfcIndexedPolyCurves are downgraded by sampling the
+        circular arc into a chord polyline. The chord count is fixed by
+        the recipe's subdivision parameter."""
+        from ifcpatch.recipes.DowngradeIndexedPolyCurve import ARC_SUBDIVISION
+
+        segments = [self.file.createIfcArcIndex((1, 2, 3))]
+        self._make_curve(segments=segments)
+        ifcpatch.execute(
+            {"input": "input.ifc", "file": self.file, "recipe": "DowngradeIndexedPolyCurve", "arguments": []}
+        )
+        polylines = self.file.by_type("IfcPolyline")
+        assert len(polylines) == 1
+        assert len(polylines[0].Points) == ARC_SUBDIVISION + 1