See #3069. Continued refactoring to not rely on users_collection[0].

src/blenderbim/blenderbim/bim/handler.py

@@ -74,19 +74,8 @@ def name_callback(obj, data):
     element = IfcStore.get_file().by_id(obj.BIMObjectProperties.ifc_definition_id)
     if not element.is_a("IfcRoot"):
         return
-    if element.is_a("IfcSpatialStructureElement") or (hasattr(element, "IsDecomposedBy") and element.IsDecomposedBy):
-        collection = obj.users_collection[0]
-        collection.name = obj.name
-    if element.is_a("IfcGrid"):
-        axis_obj = IfcStore.get_element(element.UAxes[0].id())
-        axis_collection = axis_obj.users_collection[0]
-        grid_collection = None
-        for collection in bpy.data.collections:
-            if axis_collection.name in collection.children.keys():
-                grid_collection = collection
-                break
-        if grid_collection:
-            grid_collection.name = obj.name
+    if obj.BIMObjectProperties.collection:
+        obj.BIMObjectProperties.collection.name = obj.name
     element.Name = "/".join(obj.name.split("/")[1:])
     refresh_ui_data()
 

src/blenderbim/blenderbim/bim/import_ifc.py

@@ -1330,7 +1330,7 @@ class IfcImporter:
         self.project = {"ifc": project}
         obj = tool.Ifc.get_object(project)
         if obj:
-            self.project["blender"] = obj.users_collection[0]
+            self.project["blender"] = obj.BIMObjectProperties.collection
             self.has_existing_project = True
             return
         self.project["blender"] = bpy.data.collections.new(
@@ -1392,7 +1392,7 @@ class IfcImporter:
                 obj = tool.Ifc.get_object(element)
                 if obj:
                     is_existing = True
-                    collection = obj.users_collection[0]
+                    collection = obj.BIMObjectProperties.collection
                     self.collections[element.GlobalId] = collection
             if not is_existing:
                 collection = bpy.data.collections.new(tool.Loader.get_name(element))

src/blenderbim/blenderbim/bim/module/boundary/operator.py

@@ -38,7 +38,7 @@ from blenderbim.bim.module.boundary.decorator import BoundaryDecorator
 
 
 def get_boundaries_collection(blender_space):
-    space_collection = bpy.data.collections.get(blender_space.name, blender_space.users_collection[0])
+    space_collection = blender_space.BIMObjectProperties.collection
     collection_name = f"Boundaries/{blender_space.BIMObjectProperties.ifc_definition_id}"
     boundaries_collection = space_collection.children.get(collection_name)
     if not boundaries_collection:

src/blenderbim/blenderbim/bim/module/geometry/data.py

@@ -152,10 +152,18 @@ class DerivedPlacementsData:
 
     @classmethod
     def load_collection(cls):
-        cls.collection = bpy.data.objects.get(bpy.context.active_object.users_collection[0].name)
+        cls.collection = None
         cls.collection_z = 0
-        if cls.collection:
-            cls.collection_z = cls.collection.matrix_world.translation.z
+        element = tool.Ifc.get_entity(bpy.context.active_object)
+        if not element:
+            return
+        parent = ifcopenshell.util.element.get_aggregate(element)
+        if not parent:
+            parent = ifcopenshell.util.element.get_container(element)
+        if parent:
+            cls.collection = tool.Ifc.get_object(parent)
+            if cls.collection:
+                cls.collection_z = cls.collection.matrix_world.translation.z
 
     @classmethod
     def has_collection(cls):

src/blenderbim/blenderbim/bim/module/model/grid.py

@@ -30,32 +30,20 @@ def add_object(self, context):
     obj = bpy.data.objects.new("Grid", None)
     obj.name = "Grid"
 
-    collection = bpy.data.collections.new(obj.name)
-    has_site_collection = False
-    for child in context.view_layer.layer_collection.children:
-        if "IfcProject/" not in child.name:
-            continue
-        for grandchild in child.children:
-            if "IfcSite/" not in grandchild.name:
-                continue
-            has_site_collection = True
-            grandchild.collection.children.link(collection)
-            break
-    if not has_site_collection:
-        context.view_layer.active_layer_collection.collection.children.link(collection)
+    collection = context.view_layer.active_layer_collection.collection
+    site = tool.Ifc.get().by_type("IfcSite")
+    if site:
+        site = site[0]
+        site_obj = tool.Ifc.get_object(site)
+        if site_obj:
+            collection = site_obj.BIMObjectProperties.collection or collection
+
     collection.objects.link(obj)
 
-    self.file = IfcStore.get_file()
-    if self.file:
-        bpy.ops.bim.assign_class(obj=obj.name, ifc_class="IfcGrid")
-        collection.name = obj.name
-        grid = self.file.by_id(obj.BIMObjectProperties.ifc_definition_id)
-        if has_site_collection:
-            site_obj = bpy.data.objects.get(grandchild.name)
-            if site_obj and site_obj.BIMObjectProperties.ifc_definition_id:
-                blenderbim.core.spatial.assign_container(
-                    tool.Ifc, tool.Collector, tool.Spatial, structure_obj=site_obj, element_obj=obj
-                )
+    bpy.ops.bim.assign_class(obj=obj.name, ifc_class="IfcGrid")
+    grid = tool.Ifc.get_entity(obj)
+
+    collection = obj.BIMObjectProperties.collection or collection
 
     axes_collection = bpy.data.collections.new("UAxes")
     collection.children.link(axes_collection)
@@ -73,15 +61,14 @@ def add_object(self, context):
 
         axes_collection.objects.link(obj)
 
-        if self.file:
-            result = ifcopenshell.api.run(
-                "grid.create_grid_axis",
-                self.file,
-                **{"axis_tag": tag, "uvw_axes": "UAxes", "grid": grid},
-            )
-            IfcStore.link_element(result, obj)
-            ifcopenshell.api.run("grid.create_axis_curve", self.file, **{"axis_curve": obj, "grid_axis": result})
-            obj.BIMObjectProperties.ifc_definition_id = result.id()
+        result = ifcopenshell.api.run(
+            "grid.create_grid_axis",
+            tool.Ifc.get(),
+            **{"axis_tag": tag, "uvw_axes": "UAxes", "grid": grid},
+        )
+        IfcStore.link_element(result, obj)
+        ifcopenshell.api.run("grid.create_axis_curve", tool.Ifc.get(), **{"axis_curve": obj, "grid_axis": result})
+        obj.BIMObjectProperties.ifc_definition_id = result.id()
 
     axes_collection = bpy.data.collections.new("VAxes")
     collection.children.link(axes_collection)
@@ -99,15 +86,14 @@ def add_object(self, context):
 
         axes_collection.objects.link(obj)
 
-        if self.file:
-            result = ifcopenshell.api.run(
-                "grid.create_grid_axis",
-                self.file,
-                **{"axis_tag": tag, "uvw_axes": "VAxes", "grid": grid},
-            )
-            IfcStore.link_element(result, obj)
-            ifcopenshell.api.run("grid.create_axis_curve", self.file, **{"axis_curve": obj, "grid_axis": result})
-            obj.BIMObjectProperties.ifc_definition_id = result.id()
+        result = ifcopenshell.api.run(
+            "grid.create_grid_axis",
+            tool.Ifc.get(),
+            **{"axis_tag": tag, "uvw_axes": "VAxes", "grid": grid},
+        )
+        IfcStore.link_element(result, obj)
+        ifcopenshell.api.run("grid.create_axis_curve", tool.Ifc.get(), **{"axis_curve": obj, "grid_axis": result})
+        obj.BIMObjectProperties.ifc_definition_id = result.id()
 
 
 class BIM_OT_add_object(Operator):

src/blenderbim/blenderbim/tool/collector.py

@@ -51,13 +51,17 @@ class Collector(blenderbim.core.tool.Collector):
 
         parent_collection = None
 
-        if obj.users_collection != (object_collection,) and obj.users_collection[0].name != obj.name:
-            parent_collection = obj.users_collection[0]
-        elif collection_collection and collection_collection.children.find(object_collection.name) == -1:
-            for collection in bpy.data.collections:
-                if collection.children.find(obj.users_collection[0].name) != -1:
-                    parent_collection = collection
-                    break
+        for collection in obj.users_collection:
+            if parent_collection:
+                break
+            if not collection.BIMCollectionProperties.obj:
+                continue
+            if collection.BIMCollectionProperties.obj == obj:
+                for bpy_collection in bpy.data.collections:
+                    if bpy_collection.children.find(collection.name) != -1:
+                        parent_collection = bpy_collection
+            else:
+                parent_collection = collection
 
         if not parent_collection:
             return
@@ -214,7 +218,7 @@ class Collector(blenderbim.core.tool.Collector):
         if not collection:
             collection = bpy.data.collections.new(name)
             project_obj = tool.Ifc.get_object(tool.Ifc.get().by_type("IfcProject")[0])
-            project_obj.users_collection[0].children.link(collection)
+            project_obj.BIMObjectProperties.collection.children.link(collection)
         return collection
 
     @classmethod

src/blenderbim/blenderbim/tool/misc.py

@@ -113,7 +113,8 @@ class Misc(blenderbim.core.tool.Misc):
             new_obj = obj.copy()
             new_obj.data = obj.data.copy()
 
-            obj.users_collection[0].objects.link(new_obj)
+            for collection in obj.users_collection:
+                collection.objects.link(new_obj)
 
             mod = new_obj.modifiers.new(type="BOOLEAN", name="Boolean")
             mod.object = cutter

src/blenderbim/blenderbim/tool/project.py

@@ -104,7 +104,7 @@ class Project(blenderbim.core.tool.Project):
 
     @classmethod
     def set_active_spatial_element(cls, obj):
-        collection = obj.users_collection[0]
+        collection = obj.BIMObjectProperties.collection
         queue = [bpy.context.view_layer.layer_collection]
         layer_collection = None
 

src/blenderbim/test/tool/test_collector.py

@@ -331,6 +331,8 @@ class TestSync(NewFile):
         bpy.ops.bim.create_project()
         obj = bpy.data.objects.new("IfcBuildingStorey/Name", None)
         col = bpy.data.collections.new("IfcBuildingStorey/Name")
+        obj.BIMObjectProperties.collection = col
+        col.BIMCollectionProperties.obj = obj
         element = tool.Ifc.get().createIfcBuildingStorey(Name="Name")
         tool.Ifc.link(element, obj)
         bpy.data.collections.get("IfcBuilding/My Building").children.link(col)