Roundtripping native geometry now works across different IFC schema versions

src/ifcblenderexport/Makefile

@@ -39,11 +39,13 @@ endif
 	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && rm -f selector.py
 	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && rm -f unit.py
 	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && rm -f pset.py
+	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && rm -f schema.py
 	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && wget https://raw.githubusercontent.com/IfcOpenShell/IfcOpenShell/v0.6.0/src/ifcopenshell-python/ifcopenshell/util/element.py
 	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && wget https://raw.githubusercontent.com/IfcOpenShell/IfcOpenShell/v0.6.0/src/ifcopenshell-python/ifcopenshell/util/geolocation.py
 	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && wget https://raw.githubusercontent.com/IfcOpenShell/IfcOpenShell/v0.6.0/src/ifcopenshell-python/ifcopenshell/util/selector.py
 	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && wget https://raw.githubusercontent.com/IfcOpenShell/IfcOpenShell/v0.6.0/src/ifcopenshell-python/ifcopenshell/util/unit.py
 	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && wget https://raw.githubusercontent.com/IfcOpenShell/IfcOpenShell/v0.6.0/src/ifcopenshell-python/ifcopenshell/util/pset.py
+	cd dist/blenderbim/libs/site/packages/ifcopenshell/util && wget https://raw.githubusercontent.com/IfcOpenShell/IfcOpenShell/v0.6.0/src/ifcopenshell-python/ifcopenshell/util/schema.py
 
 	# Provides Python OCC functionality for cutting IFC geometry for construction documentation
 	mkdir dist/working

src/ifcblenderexport/blenderbim/bim/export_ifc.py

@@ -9,6 +9,7 @@ import zipfile
 import tempfile
 import ifcopenshell
 import ifcopenshell.util.pset
+import ifcopenshell.util.schema
 from pathlib import Path
 from mathutils import Vector, Matrix
 from .helper import SIUnitHelper
@@ -2356,7 +2357,11 @@ class IfcExporter:
             print("Authoring an IFC definition directly is not yet implemented")
             return
         elif representation["ifc_definition_id"]:
-            entry = self.file.add(ifc.IfcStore.get_file().by_id(representation["ifc_definition_id"]))
+            if self.file.schema == ifc.IfcStore.get_file().schema:
+                entry = self.file.add(ifc.IfcStore.get_file().by_id(representation["ifc_definition_id"]))
+            else:
+                migrator = ifcopenshell.util.schema.Migrator()
+                entry = migrator.migrate(ifc.IfcStore.get_file().by_id(representation["ifc_definition_id"]), self.file)
 
             substitutions = {"contexts": []}
 
@@ -2365,7 +2370,10 @@ class IfcExporter:
             )
 
             for element in representation_elements:
-                added_element = self.file.add(element)
+                if self.file.schema == ifc.IfcStore.get_file().schema:
+                    added_element = self.file.add(element)
+                else:
+                    added_element = migrator.migrate(element, self.file)
                 if added_element.is_a("IfcGeometricRepresentationContext"):
                     substitutions["contexts"].append(added_element)
 

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

@@ -70,10 +70,10 @@ class Migrator:
             return new_file.by_id(self.migrated_ids[element.id()])
         except:
             pass
-        print("Migrating", element)
+        #print("Migrating", element)
         schema = ifcopenshell.ifcopenshell_wrapper.schema_by_name(new_file.schema)
         new_element = self.migrate_class(element, new_file)
-        print("Migrated class from {} to {}".format(element, new_element))
+        #print("Migrated class from {} to {}".format(element, new_element))
         new_element_schema = schema.declaration_by_name(new_element.is_a())
         if not hasattr(new_element_schema, "all_attributes"):
             return element # The element has no attributes, so migration is done
@@ -91,6 +91,7 @@ class Migrator:
                 new_element = new_file.create_entity(self.class_4_to_2x3[element.is_a()])
             elif new_file.schema == "IFC4":
                 print("Class migration to IFC4 not yet supported for", element)
+                pass
         return new_element
 
     def migrate_attributes(self, element, new_file, new_element, new_element_schema):
@@ -101,18 +102,18 @@ class Migrator:
         return new_element
 
     def migrate_attribute(self, attribute, element, new_file, new_element, new_element_schema):
-        print("Migrating attribute", element, new_element, attribute.name())
+        #print("Migrating attribute", element, new_element, attribute.name())
         if hasattr(element, attribute.name()):
             value = getattr(element, attribute.name())
-            print("Attribute names matched", value)
+            #print("Attribute names matched", value)
         elif new_file.schema == "IFC2X3":
             # IFC4 to IFC2X3: We know the IFC2X3 attribute name, but not its IFC4 equivalent
-            print("Searching for an equivalent", new_element, attribute.name())
+            #print("Searching for an equivalent", new_element, attribute.name())
             try:
                 equivalent_map = self.attribute_4_to_2x3[new_element.is_a()]
                 equivalent = list(equivalent_map.keys())[list(equivalent_map.values()).index(attribute.name())]
                 if hasattr(element, equivalent):
-                    print("Equivalent found", equivalent)
+                    #print("Equivalent found", equivalent)
                     value = getattr(element, equivalent)
                 else:
                     return
@@ -121,10 +122,10 @@ class Migrator:
                 return # We tried our best
         elif new_file.schema == "IFC4":
             # IFC2X3 to IFC4: We know the IFC4 attribute name, but not its IFC2X3 equivalent
-            print("Searching for an equivalent", element, new_element, attribute.name())
+            #print("Searching for an equivalent", element, new_element, attribute.name())
             try:
                 equivalent = self.attribute_4_to_2x3[new_element.is_a()][attribute.name()]
-                print("Searching for equivalent", equivalent)
+                #print("Searching for equivalent", equivalent)
                 if hasattr(element, equivalent):
                     value = getattr(element, equivalent)
                 else:
@@ -133,7 +134,7 @@ class Migrator:
                 print("Unable to find equivalent attribute of {} to migrate from {} to {}".format(attribute.name(), element, new_element))
                 return # We tried our best
 
-        print("Continuing migration of {} to migrate from {} to {}".format(attribute.name(), element, new_element))
+        #print("Continuing migration of {} to migrate from {} to {}".format(attribute.name(), element, new_element))
         if value is None and not attribute.optional():
             value = self.generate_default_value(attribute, new_file)
             if value is None: