From 76e7205692b908187b31320bed72dadb61ef9dde Mon Sep 17 00:00:00 2001
From: Dion Moult <dion@thinkmoult.com>
Date: Sun, 14 Jun 2020 19:19:54 +1000
Subject: [PATCH] Add experimental native support for faceted breps import

---
 .../blenderbim/bim/import_ifc.py              | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/ifcblenderexport/blenderbim/bim/import_ifc.py b/src/ifcblenderexport/blenderbim/bim/import_ifc.py
index 75aa2373ef..f187a2e857 100644
--- a/src/ifcblenderexport/blenderbim/bim/import_ifc.py
+++ b/src/ifcblenderexport/blenderbim/bim/import_ifc.py
@@ -363,6 +363,7 @@ class IfcImporter():
     def parse_native_elements(self):
         self.parse_native_swept_disk_solid()
         self.parse_native_extruded_area_solid()
+        self.parse_native_faceted_brep()
         if self.include_elements:
             include_global_ids = [e.GlobalId for e in self.include_elements]
             filtered_native_elements = {}
@@ -391,6 +392,10 @@ class IfcImporter():
                 continue
             self.swap_out_with_dummy_geometry(element)
 
+    def parse_native_faceted_brep(self):
+        for element in self.file.by_type('IfcFacetedBrep'):
+            self.swap_out_with_dummy_geometry(element)
+
     def swap_out_with_dummy_geometry(self, element):
         dummy_geometry = self.get_dummy_geometry()
         inverse_elements = self.file.get_inverse(element)
@@ -758,6 +763,13 @@ class IfcImporter():
                             self.create_native_swept_disk_solid(item, element), representation['matrix']),
                         'raw': item
                     })
+                elif item.is_a('IfcFacetedBrep'):
+                    bm = self.create_native_faceted_brep(item, element)
+                    if bm:
+                        bmesh.ops.transform(bm, matrix=representation['matrix'], verts=bm.verts)
+                        items.append({'blender': bm, 'raw': item})
+                    else:
+                        items.append(None)
                 else:
                     items.append(None)
 
@@ -843,6 +855,23 @@ class IfcImporter():
         a.from_mesh(mesh)
         return a
 
+    def create_native_faceted_brep(self, item, element):
+        vertex_map = {}
+        vertices = []
+        faces = []
+        vertex_index = 0
+        for face in item.Outer.CfsFaces:
+            if len(face.Bounds) > 1:
+                # TODO: implement tesselate_polygon
+                return None
+            for point in face.Bounds[0].Bound.Polygon:
+                if point.id() not in vertex_map:
+                    vertices.append([c * self.unit_scale for c in point.Coordinates])
+                    vertex_map[point.id()] = vertex_index
+                    vertex_index += 1
+            faces.append([vertex_map[p.id()] for p in face.Bounds[0].Bound.Polygon])
+        return self.bmesh_from_pydata(vertices, [], faces)
+
     def create_native_swept_disk_solid(self, item, element):
         # TODO: support inner radius, start param, and end param
         shape = ifcopenshell.geom.create_shape(self.settings_native, item.Directrix)