Forgot to commit append_asset usecase, also minor fixes

src/blenderbim/blenderbim/bim/export_ifc.py

@@ -80,9 +80,9 @@ class IfcExporter:
         for guid, obj in IfcStore.guid_map.items():
             try:
                 self.sync_object_placement(obj)
-            except:
+                self.sync_object_container(guid, obj)
-                pass
+            except ReferenceError:
-            self.sync_object_container(guid, obj)
+                pass  # The object is likely deleted
             if self.should_delete(obj):
                 to_delete.append(guid)
 
@@ -105,9 +105,10 @@ class IfcExporter:
 
     def sync_object_placement(self, obj):
         blender_matrix = np.matrix(obj.matrix_world)
-        ifc_matrix = ifcopenshell.util.placement.get_local_placement(
+        element = self.file.by_id(obj.BIMObjectProperties.ifc_definition_id)
-            self.file.by_id(obj.BIMObjectProperties.ifc_definition_id).ObjectPlacement
+        if not hasattr(element, "ObjectPlacement"):
-        )
+            return
+        ifc_matrix = ifcopenshell.util.placement.get_local_placement(element.ObjectPlacement)
         ifc_matrix[0][3] *= self.unit_scale
         ifc_matrix[1][3] *= self.unit_scale
         ifc_matrix[2][3] *= self.unit_scale

src/ifcopenshell-python/ifcopenshell/api/project/append_asset.py

@@ -0,0 +1,54 @@
+import ifcopenshell
+import ifcopenshell.api
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"element": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        element = self.file.add(self.settings["element"])
+        self.existing_contexts = self.file.by_type("IfcGeometricRepresentationContext")
+        added_contexts = [e for e in self.file.traverse(element) if e.is_a("IfcGeometricRepresentationContext")]
+        for added_context in added_contexts:
+            equivalent_existing_context = self.get_equivalent_existing_context(added_context)
+            if not equivalent_existing_context:
+                equivalent_existing_context = self.create_equivalent_context(added_context)
+            for inverse in self.file.get_inverse(added_context):
+                ifcopenshell.util.element.replace_attribute(inverse, added_context, equivalent_existing_context)
+        for added_context in added_contexts:
+            if added_context.is_a() == "IfcGeometricRepresentationContext":
+                ifcopenshell.util.element.remove_deep(self.file, added_context)
+        return element
+
+    def get_equivalent_existing_context(self, added_context):
+        for context in self.existing_contexts:
+            if context.is_a() != added_context.is_a():
+                continue
+            if context.is_a("IfcGeometricRepresentationSubContext"):
+                if (
+                    context.ContextType == added_context.ContextType
+                    and context.ContextIdentifier == added_context.ContextIdentifier
+                    and context.TargetView == added_context.TargetView
+                ):
+                    return context
+            elif (
+                context.ContextType == added_context.ContextType
+                and context.ContextIdentifier == added_context.ContextIdentifier
+            ):
+                return context
+
+    def create_equivalent_context(self, added_context):
+        if added_context.is_a("IfcGeometricRepresentationSubContext"):
+            return ifcopenshell.api.run(
+                "context.add_context",
+                context=added_context.ContextType,
+                subcontext=added_context.ContextIdentifier,
+                target_view=added_context.TargetView,
+            )
+        return ifcopenshell.api.run(
+            "context.add_context", context=added_context.ContextType, subcontext=added_context.ContextIdentifier
+        )