Implement model offset workaround for Bentley ProStructures. See #1047.

In an ideal world, projects are geolocated properly in IFC. If not, they tend to store it in the spatial structure placement which is then inherited (e.g. Revit) or in the geometry coords themselves (e.g. 12D). In the case of Bentley ProStructures, it seemas s though large coords can be found in both object placements and geometry coords and who knows where else. In this scenario, a model offset is a clean solution rather than patching. However, it will lead to mesh inaccuracies in Blender due to the mixing of large numbers in both object locations and geometry coordinates.

Also model offsetting is useful to have available in general.

src/ifcblenderexport/blenderbim/bim/import_ifc.py

@@ -17,6 +17,7 @@ import multiprocessing
 import zipfile
 import tempfile
 from pathlib import Path
+from itertools import cycle
 from . import helper
 from . import schema
 from . import ifc
@@ -1933,7 +1934,13 @@ class IfcImporter():
                 num_vertex_indices = len(geometry.faces)
 
                 mesh.vertices.add(num_vertices)
-                mesh.vertices.foreach_set('co', geometry.verts)
+                if self.ifc_import_settings.should_offset_model:
+                    # Potentially, there is a smarter way to do this. See #1047
+                    v_index = cycle((0, 1, 2))
+                    verts = [v+self.ifc_import_settings.model_offset_coordinates[next(v_index)] for v in geometry.verts]
+                    mesh.vertices.foreach_set('co', verts)
+                else:
+                    mesh.vertices.foreach_set('co', geometry.verts)
                 mesh.loops.add(num_vertex_indices)
                 mesh.loops.foreach_set('vertex_index', geometry.faces)
                 mesh.polygons.add(num_loops)
@@ -2128,6 +2135,8 @@ class IfcImportSettings:
         settings.should_merge_by_material = scene_bim.import_should_merge_by_material
         settings.should_merge_materials_by_colour = scene_bim.import_should_merge_materials_by_colour
         settings.should_clean_mesh = scene_bim.import_should_clean_mesh
+        settings.should_offset_model = scene_bim.import_should_offset_model
+        settings.model_offset_coordinates = [float(o) for o in scene_bim.import_model_offset_coordinates.split(',')] if scene_bim.import_model_offset_coordinates else (0, 0, 0)
         settings.deflection_tolerance = scene_bim.import_deflection_tolerance
         settings.angular_tolerance = scene_bim.import_angular_tolerance
         return settings

src/ifcblenderexport/blenderbim/bim/prop.py

@@ -1216,6 +1216,8 @@ class BIMProperties(PropertyGroup):
     import_should_clean_mesh: BoolProperty(name="Import and Clean Mesh", default=True)
     import_deflection_tolerance: FloatProperty(name="Import Deflection Tolerance", default=0.001)
     import_angular_tolerance: FloatProperty(name="Import Angular Tolerance", default=0.5)
+    import_should_offset_model: BoolProperty(name="Import and Offset Model", default=False)
+    import_model_offset_coordinates: StringProperty(name="Model Offset Coordinates", default='0,0,0')
     qa_reject_element_reason: StringProperty(name="Element Rejection Reason")
     person: EnumProperty(items=getPersons, name="Person")
     organisation: EnumProperty(items=getOrganisations, name="Organisation")

src/ifcblenderexport/blenderbim/bim/ui.py

@@ -1754,6 +1754,13 @@ class BIM_PT_mvd(Panel):
         row = layout.row()
         row.prop(bim_properties, 'import_should_ignore_site_coordinates')
 
+        layout.label(text='ProStructures Workarounds:')
+
+        row = layout.row()
+        row.prop(bim_properties, 'import_should_offset_model')
+        row = layout.row()
+        row.prop(bim_properties, 'import_model_offset_coordinates')
+
         layout.label(text='12D Workarounds:')
 
         row = layout.row()