Add api.structural.assign_product, assign_to_building, and api.geometry.add_topology_representation

assign_product creates IfcRelAssignsToProduct linking a structural member to
a physical building element. assign_to_building creates IfcRelServicesBuildings
linking a structural analysis model to a building. add_topology_representation
creates IfcTopologyRepresentation for structural elements, inferring the
representation type from the item class.

Generated with the assistance of an AI coding tool.

src/ifcopenshell-python/ifcopenshell/api/geometry/__init__.py

@@ -25,6 +25,7 @@ geometry extrusions).
 
 from .. import wrap_usecases
 from .add_axis_representation import add_axis_representation
+from .add_topology_representation import add_topology_representation
 from .add_boolean import add_boolean
 from .clip_solid import clip_solid
 from .clip_solid_bounded import clip_solid_bounded
@@ -63,6 +64,7 @@ wrap_usecases(__path__, __name__)
 
 __all__ = [
     "add_axis_representation",
+    "add_topology_representation",
     "add_boolean",
     "clip_solid",
     "clip_solid_bounded",

src/ifcopenshell-python/ifcopenshell/api/geometry/add_topology_representation.py

@@ -0,0 +1,98 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2026 Dion Moult <dion@thinkmoult.com>
+#
+# 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.
+
+from typing import Optional
+
+import ifcopenshell
+
+
+_ITEM_TYPE_TO_REP_TYPE = {
+    "IfcVertex": "Vertex",
+    "IfcVertexPoint": "Vertex",
+    "IfcEdge": "Edge",
+    "IfcOrientedEdge": "Edge",
+    "IfcEdgeCurve": "Edge",
+    "IfcEdgeLoop": "Edge",
+    "IfcPath": "Edge",
+    "IfcFace": "Face",
+    "IfcFaceSurface": "Face",
+    "IfcAdvancedFace": "Face",
+    "IfcClosedShell": "Face",
+    "IfcOpenShell": "Face",
+    "IfcConnectedFaceSet": "Face",
+}
+
+
+def add_topology_representation(
+    file: ifcopenshell.file,
+    context: ifcopenshell.entity_instance,
+    item: ifcopenshell.entity_instance,
+    representation_identifier: Optional[str] = None,
+    representation_type: Optional[str] = None,
+) -> ifcopenshell.entity_instance:
+    """Adds an IfcTopologyRepresentation for a structural element
+
+    Structural analysis elements (IfcStructuralSurfaceMember,
+    IfcStructuralCurveMember) use topology representations rather than solid
+    geometry. This is analogous to :func:`add_axis_representation` and
+    :func:`add_profile_representation` but produces an
+    IfcTopologyRepresentation instead of an IfcShapeRepresentation.
+
+    The representation type ("Face", "Edge", "Vertex") is inferred from the
+    item's IFC class if not provided explicitly.
+
+    :param context: The IfcGeometricRepresentationContext for the
+        representation, typically a Reference context.
+    :param item: The IfcTopologicalRepresentationItem (e.g. IfcFaceSurface,
+        IfcEdge) to include in the representation.
+    :param representation_identifier: The RepresentationIdentifier string.
+        Defaults to the context's ContextIdentifier.
+    :param representation_type: The RepresentationType string ("Face",
+        "Edge", "Vertex"). Inferred from item class if not given.
+    :return: The newly created IfcTopologyRepresentation entity.
+
+    Example:
+
+    .. code:: python
+
+        context = ifcopenshell.util.representation.get_context(
+            model, "Model", "Reference", "GRAPH_VIEW")
+        face = model.createIfcFaceSurface(bounds, surface, True)
+        rep = ifcopenshell.api.geometry.add_topology_representation(
+            model, context=context, item=face)
+        ifcopenshell.api.geometry.assign_representation(
+            model, product=member, representation=rep)
+    """
+    if representation_identifier is None:
+        representation_identifier = context.ContextIdentifier
+
+    if representation_type is None:
+        for ifc_class, rep_type in _ITEM_TYPE_TO_REP_TYPE.items():
+            if item.is_a(ifc_class):
+                representation_type = rep_type
+                break
+        else:
+            representation_type = "Undefined"
+
+    return file.createIfcTopologyRepresentation(
+        context,
+        representation_identifier,
+        representation_type,
+        [item],
+    )