util.shape for materials and material_ids

src/bonsai/bonsai/bim/import_ifc.py

@@ -70,17 +70,6 @@ class MaterialCreator:
 
         self.mesh = mesh
         self.obj = obj
-
-        # mesh["ios_materials"] can contain:
-        # - ifc style id if style assigned to the representation items directly
-        # or through material with a style;
-        # - ifc material id if both true:
-        #   - element has a material without a style;
-        #   - there are parts of the geometry that has no other style assigned to them;
-        # - -1 in case if there is no material;
-        # - 0 in case if there are default materials used.
-        # Though 0 value will not occur as we don't use default materials in IfcImporter.
-
         self.parsed_meshes.add(self.mesh.name)
         self.load_texture_maps(shape_has_openings)
         self.assign_material_slots_to_faces()

src/bonsai/bonsai/bim/module/project/operator.py

@@ -1567,7 +1567,7 @@ class LoadLinkedProject(bpy.types.Operator):
                     has_processed_chunk = False
 
                     ms = np.vstack([default_mat, ifcopenshell.util.shape.get_material_colors(shape.geometry)])
-                    mi = np.frombuffer(shape.geometry.material_ids_buffer, dtype=np.int32)
+                    mi = ifcopenshell.util.shape.get_faces_material_style_ids(shape.geometry)
                     for geom_material_idx, geom_material in enumerate(shape.geometry.materials):
                         if not geom_material.instance_id():
                             ms[geom_material_idx + 1] = (0.8, 0.8, 0.8, 1)

src/ifcopenshell-python/ifcopenshell/util/shape.py

@@ -20,6 +20,7 @@ import shapely
 import shapely.ops
 import numpy as np
 import numpy.typing as npt
+import ifcopenshell.ifcopenshell_wrapper as W
 import ifcopenshell.util.element
 import ifcopenshell.util.placement
 import ifcopenshell.util.representation
@@ -300,6 +301,30 @@ def get_normals(geometry: ShapeType) -> npt.NDArray[np.float64]:
     return np.frombuffer(geometry.normals_buffer, dtype="d").reshape(-1, 3)
 
 
+def get_shape_material_styles(geometry: ShapeType) -> tuple[W.style, ...]:
+    """Get list of material styles.
+
+    Possible values for `style.instance_id()`:
+    - IFC style id if style assigned to the representation items directly
+    or through material with a style;
+    - IFC material id if both true:
+      - element has a material without a style;
+      - there are parts of the geometry that has no other style assigned to them;
+    - -1 in case if there is no material;
+    - 0 in case if there are default materials used.
+    """
+    return geometry.materials
+
+
+def get_faces_material_style_ids(geometry: ShapeType) -> npt.NDArray[np.int32]:
+    """Get material styles ids for the geometry faces.
+
+    Return a list of corresponding indices of styles from get_shape_material_styles for each face.
+    If face has no style assigned, index -1 is used.
+    """
+    return np.frombuffer(geometry.material_ids_buffer, dtype="i")
+
+
 def get_faces_representation_item_ids(geometry: ShapeType) -> npt.NDArray[np.int32]:
     """Get representation item ids for the geometry faces."""
     return np.frombuffer(geometry.item_ids_buffer, dtype="i")