Add UV texture support for IfcTessellatedFaceSet (#3523)

* Add texture support for IfcIndexedTextureMap

* fix description.

* Fix posible duplicate coordinate index issue

* Clean up code.

* revert default clean_mesh.

* Fix errors.

* change to EXTEND mode when not RepeatS/T

* remove tris merge to support mix quads and tris.

src/blenderbim/blenderbim/bim/import_ifc.py

@@ -52,6 +52,7 @@ class FileCopy(threading.Thread):
 class MaterialCreator:
     def __init__(self, ifc_import_settings, ifc_importer):
         self.mesh = None
+        self.obj = None
         self.materials = {}
         self.styles = {}
         self.parsed_meshes = set()
@@ -60,6 +61,8 @@ class MaterialCreator:
 
     def create(self, element, obj, mesh):
         self.mesh = mesh
+        # as ifcopenshell triangulates the mesh, we need to merge it to quads again
+        self.obj = obj
         if (hasattr(element, "Representation") and not element.Representation) or (
             hasattr(element, "RepresentationMaps") and not element.RepresentationMaps
         ):
@@ -132,10 +135,55 @@ class MaterialCreator:
             return
         for style_id in style_ids:
             material = self.styles[style_id]
+            ifc_coordinate_id = material.BIMMaterialProperties.ifc_coordinate_id
+            if ifc_coordinate_id != 0:
+                self.load_texture_map(tool.Ifc.get().by_id(ifc_coordinate_id))
             if self.mesh.materials.find(material.name) == -1:
                 self.mesh.materials.append(material)
         return True
 
+    def load_texture_map(self, coordinates):
+        # Get a BMesh representation
+        bm = bmesh.new()
+        bm.from_mesh(self.mesh)
+        uv_layer = bm.loops.layers.uv.verify()
+
+        # remap the faceset CoordList index to the vertices in blender mesh
+        coordinates_remap = []
+        for co in coordinates.MappedTo.Coordinates.CoordList:
+            co = mathutils.Vector(co)
+            index = next(v.index for v in bm.verts if (v.co - co).length_squared < 1e-5)
+            coordinates_remap.append(index)
+
+        faces_remap = None
+        texture_map = None
+        if coordinates.is_a("IfcIndexedPolygonalTextureMap"):
+            faces_remap = [[coordinates_remap[i-1] for i in tex_coord_index.TexCoordsOf.CoordIndex]
+                        for tex_coord_index in coordinates.TexCoordIndices]
+            texture_map = [tex_coord_index.TexCoordIndex for tex_coord_index in coordinates.TexCoordIndices]
+        elif coordinates.is_a("IfcIndexedTriangleTextureMap"):
+            faces_remap = [[coordinates_remap[i-1] for i in triangle_face]
+                        for triangle_face in coordinates.MappedTo.CoordIndex]
+            texture_map = coordinates.TexCoordIndex
+
+        # apply uv to each face
+        for bface in bm.faces:
+            face = [loop.vert.index for loop in bface.loops]
+            # find the corresponding TexCoordIndex by matching ifc faceset with blender face
+            # remap TexCoordIndex as the loop start may different from blender face
+            texCoordIndex = next(
+                [tex_coord_index[face_remap.index(i)] for i in face]
+                for tex_coord_index, face_remap in zip(texture_map, faces_remap)
+                if all(i in face_remap for i in face)
+            )
+            # apply uv to each loop
+            for loop, i in zip(bface.loops, texCoordIndex):
+                loop[uv_layer].uv = coordinates.TexCoords.TexCoordsList[i-1]
+
+        # Finish up, write the bmesh back to the mesh
+        bm.to_mesh(self.mesh)
+        bm.free()
+
     def assign_material_slots_to_faces(self):
         if "ios_materials" not in self.mesh or not self.mesh["ios_materials"]:
             return

src/blenderbim/blenderbim/bim/prop.py

@@ -427,6 +427,7 @@ class BIMMaterialProperties(PropertyGroup):
     attributes: CollectionProperty(name="Attributes", type=Attribute)
     # In Blender, a material object can map to an IFC material, IFC surface style, or both
     ifc_style_id: IntProperty(name="IFC Style ID")
+    ifc_coordinate_id: IntProperty(name="IFC Coordinate ID")
     shading_checksum: StringProperty(name="Shading Checksum")
 
 

src/blenderbim/blenderbim/tool/loader.py

@@ -308,8 +308,10 @@ class Loader(blenderbim.core.tool.Loader):
                     image = bpy.data.images.load(image_url)
                     node.image = image
                     blender_material.node_tree.links.new(node.outputs[0], bsdf.inputs["Base Color"])
-                    blender_material.node_tree.links.new(node.outputs[1], bsdf.inputs["Alpha"])
-                    blender_material.blend_method = "BLEND"
+                    # leave it to default(OPAQUE) when no Transparency defined
+                    if transparency := rendering_style.get("Transparency", None):
+                        blender_material.node_tree.links.new(node.outputs[1], bsdf.inputs["Alpha"])
+                        blender_material.blend_method = "BLEND"
 
             elif reflectance_method == "FLAT":
                 bsdf = tool.Blender.get_material_node(blender_material, "MIX_SHADER")
@@ -328,7 +330,16 @@ class Loader(blenderbim.core.tool.Loader):
 
                 blender_material.node_tree.links.new(node.outputs[0], bsdf.inputs[2])
 
+            # extend the image by repeating pixels on its edges if RepeatS or RepeatT is False
+            repeat_s = texture.get("RepeatS", True)
+            repeat_t = texture.get("RepeatT", True)
+            if node and (not repeat_s or not repeat_t):
+                node.extension = "EXTEND"
+
             # TODO: add support for texture data not ifc elements
+            # IsMappedBy could only get with the entity_instance for IFC4/IFC4x3
+            if isinstance(texture, dict):
+                texture = tool.Ifc.get().by_id(texture['id'])
             if node and getattr(texture, "IsMappedBy", None):
                 coordinates = texture.IsMappedBy[0]
                 coord = blender_material.node_tree.nodes.new(type="ShaderNodeTexCoord")
@@ -339,3 +350,5 @@ class Loader(blenderbim.core.tool.Loader):
                     blender_material.node_tree.links.new(coord.outputs["Camera"], node.inputs["Vector"])
                 else:
                     blender_material.node_tree.links.new(coord.outputs["UV"], node.inputs["Vector"])
+                    # save the TextureMap id for set uv when set material to mesh
+                    blender_material.BIMMaterialProperties.ifc_coordinate_id = coordinates.id()