diff --git a/src/bonsai/bonsai/bim/handler.py b/src/bonsai/bonsai/bim/handler.py
index 88e785194f..fc45d6c01c 100644
--- a/src/bonsai/bonsai/bim/handler.py
+++ b/src/bonsai/bonsai/bim/handler.py
@@ -347,8 +347,8 @@ def load_post(scene):
 
     # Bonsai overlays
     georeference_props = tool.Georeference.get_georeference_props()
-    aggregate_props = bpy.context.scene.BIMAggregateProperties
-    nest_props = bpy.context.scene.BIMNestProperties
+    aggregate_props = tool.Aggregate.get_aggregate_props()
+    nest_props = tool.Nest.get_nest_props()
     model_props = tool.Model.get_model_props()
     if georeference_props.should_visualise:
         GeoreferenceDecorator.install(bpy.context)
diff --git a/src/bonsai/bonsai/bim/module/aggregate/decorator.py b/src/bonsai/bonsai/bim/module/aggregate/decorator.py
index 239253ec2a..347daae714 100644
--- a/src/bonsai/bonsai/bim/module/aggregate/decorator.py
+++ b/src/bonsai/bonsai/bim/module/aggregate/decorator.py
@@ -20,6 +20,7 @@ import blf
 import bpy
 import gpu
 import ifcopenshell
+import ifcopenshell.util.element
 import bonsai.tool as tool
 from bpy.types import SpaceView3D
 from bpy_extras import view3d_utils
@@ -162,7 +163,8 @@ class AggregateDecorator:
         batch.draw(shader)
 
     def draw_aggregate(self, context):
-        if context.scene.BIMAggregateProperties.in_aggregate_mode:
+        props = tool.Aggregate.get_aggregate_props()
+        if props.in_aggregate_mode:
             return
         self.addon_prefs = tool.Blender.get_addon_preferences()
         decorator_color_special = self.addon_prefs.decorator_color_special
@@ -210,7 +212,7 @@ class AggregateDecorator:
             self.draw_batch("LINES", line_y, color, [(0, 1)])
             line_z = (location - Vector((0.0, 0.0, size)), location + Vector((0.0, 0.0, size)))
             self.draw_batch("LINES", line_z, color, [(0, 1)])
-            if context.scene.BIMAggregateProperties.in_aggregate_mode:
+            if props.in_aggregate_mode:
                 return
             parts = ifcopenshell.util.element.get_parts(tool.Ifc.get_entity(aggregate))
             parts_objs = [tool.Ifc.get_object(p) for p in parts]
@@ -261,7 +263,7 @@ class AggregateModeDecorator:
             return
         region = context.region
         rv3d = region.data
-        props = context.scene.BIMAggregateProperties
+        props = tool.Aggregate.get_aggregate_props()
 
         aggregate_obj = props.editing_aggregate
         if not aggregate_obj:
@@ -292,7 +294,7 @@ class AggregateModeDecorator:
     def draw_aggregate_empty(self, context):
         if context.mode == "EDIT_MESH":
             return
-        props = context.scene.BIMAggregateProperties
+        props = tool.Aggregate.get_aggregate_props()
         aggregate_obj = props.editing_aggregate
         if not aggregate_obj:
             return
diff --git a/src/bonsai/bonsai/bim/module/aggregate/operator.py b/src/bonsai/bonsai/bim/module/aggregate/operator.py
index c324037b89..f84dab2186 100644
--- a/src/bonsai/bonsai/bim/module/aggregate/operator.py
+++ b/src/bonsai/bonsai/bim/module/aggregate/operator.py
@@ -23,6 +23,7 @@ import ifcopenshell.util.element
 import bonsai.tool as tool
 import bonsai.core.aggregate as core
 import bonsai.core.spatial
+from typing import TYPE_CHECKING
 
 
 class BIM_OT_aggregate_assign_object(bpy.types.Operator, tool.Ifc.Operator):
@@ -37,16 +38,23 @@ class BIM_OT_aggregate_assign_object(bpy.types.Operator, tool.Ifc.Operator):
     relating_object: bpy.props.IntProperty()
     related_object: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        relating_object: int
+        related_object: int
+
     def _execute(self, context):
         relating_obj = None
         if self.relating_object:
             relating_obj = tool.Ifc.get_object(tool.Ifc.get().by_id(self.relating_object))
+            assert relating_obj
         elif self.related_object:
             aggregate = ifcopenshell.util.element.get_aggregate(tool.Ifc.get().by_id(self.related_object))
             if aggregate:
                 relating_obj = tool.Ifc.get_object(aggregate)
-        elif context.active_object:
+                assert relating_obj
+        else:
             relating_obj = context.active_object
+
         if not relating_obj:
             self.report({"ERROR"}, "No relating object is provided.")
             return
@@ -66,7 +74,7 @@ class BIM_OT_aggregate_assign_object(bpy.types.Operator, tool.Ifc.Operator):
                     relating_obj=relating_obj,
                     related_obj=obj,
                 )
-                props = context.scene.BIMAggregateProperties
+                props = tool.Aggregate.get_aggregate_props()
                 if relating_obj == props.editing_aggregate and props.in_aggregate_mode:
                     new_editing_obj = props.editing_objects.add()
                     new_editing_obj.obj = obj
@@ -182,7 +190,7 @@ class BIM_OT_add_aggregate(bpy.types.Operator, tool.Ifc.Operator):
                 )
             core.assign_object(tool.Ifc, tool.Aggregate, tool.Collector, relating_obj=aggregate, related_obj=obj)
 
-    def create_aggregate(self, context, ifc_class, aggregate_name):
+    def create_aggregate(self, context: bpy.types.Context, ifc_class: str, aggregate_name: str) -> bpy.types.Object:
         aggregate = bpy.data.objects.new(aggregate_name, None)
         aggregate.location = context.scene.cursor.location
         bpy.ops.bim.assign_class(obj=aggregate.name, ifc_class=ifc_class)
@@ -388,7 +396,7 @@ class BIM_OT_toggle_aggregate_mode_local_view(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def execute(self, context):
-        props = context.scene.BIMAggregateProperties
+        props = tool.Aggregate.get_aggregate_props()
         objs = [o.obj for o in props.editing_objects]
         if props.in_aggregate_mode:
             if context.space_data.local_view:
diff --git a/src/bonsai/bonsai/bim/module/aggregate/prop.py b/src/bonsai/bonsai/bim/module/aggregate/prop.py
index 1d524b3645..0fb63661b3 100644
--- a/src/bonsai/bonsai/bim/module/aggregate/prop.py
+++ b/src/bonsai/bonsai/bim/module/aggregate/prop.py
@@ -33,6 +33,7 @@ from bpy.props import (
     CollectionProperty,
 )
 from bonsai.bim.module.aggregate.decorator import AggregateDecorator, AggregateModeDecorator
+from typing import TYPE_CHECKING, Union
 
 
 def can_aggregate(relating_obj: bpy.types.Object, related_obj: bpy.types.Object) -> bool:
@@ -98,12 +99,22 @@ class BIMObjectAggregateProperties(PropertyGroup):
         poll=poll_related_object,
     )
 
+    if TYPE_CHECKING:
+        is_editing: bool
+        relating_object: Union[bpy.types.Object, None]
+        related_object: Union[bpy.types.Object, None]
+
 
 class Objects(bpy.types.PropertyGroup):
     obj: PointerProperty(type=bpy.types.Object)
     previous_display_type: bpy.props.StringProperty(default="TEXTURED")
     previous_hide_select: bpy.props.BoolProperty(default=False)
 
+    if TYPE_CHECKING:
+        obj: Union[bpy.types.Object, None]
+        previous_display_type: str
+        previous_hide_select: bool
+
 
 class BIMAggregateProperties(PropertyGroup):
     in_aggregate_mode: BoolProperty(name="In Edit Mode", update=update_aggregate_mode_decorator)
@@ -115,3 +126,10 @@ class BIMAggregateProperties(PropertyGroup):
         default=False,
         update=update_aggregate_decorator,
     )
+
+    if TYPE_CHECKING:
+        in_aggregate_mode: bool
+        editing_aggregate: Union[bpy.types.Object, None]
+        editing_objects: bpy.types.bpy_prop_collection_idprop[Objects]
+        not_editing_objects: bpy.types.bpy_prop_collection_idprop[Objects]
+        aggregate_decorator: bool
diff --git a/src/bonsai/bonsai/bim/module/aggregate/ui.py b/src/bonsai/bonsai/bim/module/aggregate/ui.py
index 0755d3a54f..91a4e138f4 100644
--- a/src/bonsai/bonsai/bim/module/aggregate/ui.py
+++ b/src/bonsai/bonsai/bim/module/aggregate/ui.py
@@ -49,11 +49,13 @@ class BIM_PT_aggregate(Panel):
         layout = self.layout
         row = layout.row()
         row.label(text="Aggregate Decorator")
-        row.prop(context.scene.BIMAggregateProperties, "aggregate_decorator", icon="HIDE_OFF", text="")
+        props = tool.Aggregate.get_aggregate_props()
+        row.prop(props, "aggregate_decorator", icon="HIDE_OFF", text="")
         if not AggregateData.is_loaded:
             AggregateData.load()
 
-        props = context.active_object.BIMObjectAggregateProperties
+        assert (obj := context.active_object)
+        props = tool.Aggregate.get_object_aggregate_props(obj)
 
         if props.is_editing:
             row = layout.row()
@@ -131,9 +133,8 @@ class BIM_PT_linked_aggregate(Panel):
         if not AggregateData.is_loaded:
             AggregateData.load()
 
-        obj = context.active_object
-        element = tool.Ifc.get_entity(obj)
-        props = obj.BIMObjectAggregateProperties
+        assert (obj := context.active_object)
+        assert (element := tool.Ifc.get_entity(obj))
         row = layout.row(align=True)
 
         if element.Decomposes:
diff --git a/src/bonsai/bonsai/bim/module/geometry/operator.py b/src/bonsai/bonsai/bim/module/geometry/operator.py
index 3062aa332c..d779e52765 100644
--- a/src/bonsai/bonsai/bim/module/geometry/operator.py
+++ b/src/bonsai/bonsai/bim/module/geometry/operator.py
@@ -1929,7 +1929,7 @@ class OverrideEscape(bpy.types.Operator):
             tool.Geometry.disable_item_mode()
         elif tool.Model.get_model_props().openings:
             bpy.ops.bim.hide_all_openings()
-        elif context.scene.BIMAggregateProperties.in_aggregate_mode:
+        elif tool.Aggregate.get_aggregate_props().in_aggregate_mode:
             bpy.ops.bim.disable_aggregate_mode()
         elif active_object := context.active_object:
             if tool.Blender.Modifier.try_canceling_editing_modifier_parameters_or_path(active_object):
@@ -1953,24 +1953,26 @@ class OverrideModeSetEdit(bpy.types.Operator, tool.Ifc.Operator):
 
     def _execute(self, context):
         selected_objs = context.selected_objects  # Purposely exclude active object
+        aprops = tool.Aggregate.get_aggregate_props()
+        nprops = tool.Nest.get_nest_props()
 
         if self.has_aggregates(selected_objs):
-            if not context.scene.BIMAggregateProperties.in_aggregate_mode:
+            if not aprops.in_aggregate_mode:
                 bonsai.core.aggregate.enable_aggregate_mode(tool.Aggregate, context.active_object)
                 return {"FINISHED"}
 
         if self.has_nests(selected_objs):
-            if not context.scene.BIMNestProperties.in_nest_mode:
+            if not nprops.in_nest_mode:
                 bonsai.core.nest.enable_nest_mode(tool.Nest, context.active_object)
                 return {"FINISHED"}
 
         if len(selected_objs) == 1 and context.active_object == selected_objs[0]:
             self.handle_single_object(context, context.active_object)
         elif len(selected_objs) == 0:
-            if context.scene.BIMAggregateProperties.in_aggregate_mode:
+            if aprops.in_aggregate_mode:
                 bonsai.core.aggregate.disable_aggregate_mode(tool.Aggregate)
                 return {"FINISHED"}
-            if context.scene.BIMNestProperties.in_nest_mode:
+            if nprops.in_nest_mode:
                 bonsai.core.nest.disable_nest_mode(tool.Nest)
                 return {"FINISHED"}
             tool.Geometry.disable_item_mode()
@@ -1981,9 +1983,10 @@ class OverrideModeSetEdit(bpy.types.Operator, tool.Ifc.Operator):
         element = tool.Ifc.get_entity(obj)
         props = tool.Geometry.get_geometry_props()
         pprops = tool.Project.get_project_props()
+        aprops = tool.Aggregate.get_aggregate_props()
         if obj == props.representation_obj:
             self.report({"ERROR"}, f"Element '{obj.name}' is in item mode and cannot be edited directly")
-        elif obj in [o.obj for o in context.scene.BIMAggregateProperties.not_editing_objects]:
+        elif obj in [o.obj for o in aprops.not_editing_objects]:
             obj.select_set(False)
             self.report(
                 {"ERROR"}, f"Element '{obj.name}' does not belong to this aggregate and cannot be edited directly"
@@ -2099,7 +2102,8 @@ class OverrideModeSetEdit(bpy.types.Operator, tool.Ifc.Operator):
                 continue
             aggregate = ifcopenshell.util.element.get_aggregate(element)
             parts = ifcopenshell.util.element.get_parts(element)
-            if (aggregate or parts) and not bpy.context.scene.BIMAggregateProperties.in_aggregate_mode:
+            props = tool.Aggregate.get_aggregate_props()
+            if (aggregate or parts) and not props.in_aggregate_mode:
                 return True
             else:
                 return False
@@ -2111,7 +2115,8 @@ class OverrideModeSetEdit(bpy.types.Operator, tool.Ifc.Operator):
                 continue
             nest = ifcopenshell.util.element.get_nest(element)
             components = ifcopenshell.util.element.get_components(element)
-            if (nest or components) and not bpy.context.scene.BIMNestProperties.in_nest_mode:
+            props = tool.Nest.get_nest_props()
+            if (nest or components) and not props.in_nest_mode:
                 return True
             else:
                 return False
@@ -3270,7 +3275,7 @@ class OverrideMove(bpy.types.Operator):
             self.new_active_obj = obj
 
         # Get aggregates
-        props = context.scene.BIMAggregateProperties
+        props = tool.Aggregate.get_aggregate_props()
         not_editing_objs = [o.obj for o in props.not_editing_objects]
         aggregates_to_move = []
         for obj in context.selected_objects:
@@ -3305,7 +3310,7 @@ class OverrideMove(bpy.types.Operator):
             return {"FINISHED"}
 
         # Get nests
-        props = context.scene.BIMNestProperties
+        props = tool.Nest.get_nest_props()
         not_editing_objs = [o.obj for o in props.not_editing_objects]
         nests_to_move = []
         for obj in context.selected_objects:
diff --git a/src/bonsai/bonsai/bim/module/model/workspace.py b/src/bonsai/bonsai/bim/module/model/workspace.py
index b4814a4d86..42a767e726 100644
--- a/src/bonsai/bonsai/bim/module/model/workspace.py
+++ b/src/bonsai/bonsai/bim/module/model/workspace.py
@@ -717,12 +717,14 @@ class EditObjectUI:
             AuthoringData.load(ifc_element_type)
 
         if context.region.type == "TOOL_HEADER":
-            if context.scene.BIMAggregateProperties.in_aggregate_mode:
+            aprops = tool.Aggregate.get_aggregate_props()
+            if aprops.in_aggregate_mode:
                 layout.label(text=f"Aggregate Mode", icon="EMPTY_AXIS")
                 row = cls.layout.row(align=True)
                 op = row.operator("bim.disable_aggregate_mode", text="", icon="X")
                 op = row.operator("bim.toggle_aggregate_mode_local_view", text="", icon="ZOOM_SELECTED")
-            if context.scene.BIMNestProperties.in_nest_mode:
+            nprops = tool.Nest.get_nest_props()
+            if nprops.in_nest_mode:
                 layout.label(text=f"Nest Mode", icon="EMPTY_AXIS")
                 row = cls.layout.row(align=True)
                 op = row.operator("bim.disable_nest_mode", text="", icon="X")
diff --git a/src/bonsai/bonsai/bim/module/nest/decorator.py b/src/bonsai/bonsai/bim/module/nest/decorator.py
index 64f3083b78..5a16ef8e44 100644
--- a/src/bonsai/bonsai/bim/module/nest/decorator.py
+++ b/src/bonsai/bonsai/bim/module/nest/decorator.py
@@ -20,6 +20,7 @@ import blf
 import bpy
 import gpu
 import ifcopenshell
+import ifcopenshell.util.element
 import bonsai.tool as tool
 from bpy.types import SpaceView3D
 from bpy_extras import view3d_utils
@@ -162,8 +163,9 @@ class NestDecorator:
         shader.uniform_float("color", color)
         batch.draw(shader)
 
-    def draw_nest(self, context):
-        if context.scene.BIMNestProperties.in_nest_mode:
+    def draw_nest(self, context: bpy.types.Context) -> None:
+        props = tool.Nest.get_nest_props()
+        if props.in_nest_mode:
             return
         self.addon_prefs = tool.Blender.get_addon_preferences()
         decorator_color_special = self.addon_prefs.decorator_color_special
@@ -262,7 +264,7 @@ class NestModeDecorator:
             return
         region = context.region
         rv3d = region.data
-        props = context.scene.BIMNestProperties
+        props = tool.Nest.get_nest_props()
 
         aggregate_obj = props.editing_nest
         if not aggregate_obj:
@@ -291,7 +293,7 @@ class NestModeDecorator:
     def draw_nest_empty(self, context):
         if context.mode == "EDIT_MESH":
             return
-        props = context.scene.BIMNestProperties
+        props = tool.Nest.get_nest_props()
         nest_obj = props.editing_nest
         if not nest_obj:
             return
diff --git a/src/bonsai/bonsai/bim/module/nest/operator.py b/src/bonsai/bonsai/bim/module/nest/operator.py
index f3247817ec..68b6839e79 100644
--- a/src/bonsai/bonsai/bim/module/nest/operator.py
+++ b/src/bonsai/bonsai/bim/module/nest/operator.py
@@ -158,7 +158,7 @@ class BIM_OT_toggle_nest_mode_local_view(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def execute(self, context):
-        props = context.scene.BIMNestProperties
+        props = tool.Nest.get_nest_props()
         objs = [o.obj for o in props.editing_objects]
         if props.in_nest_mode:
             if context.space_data.local_view:
diff --git a/src/bonsai/bonsai/bim/module/nest/prop.py b/src/bonsai/bonsai/bim/module/nest/prop.py
index d5e48b2479..6cb787b3d4 100644
--- a/src/bonsai/bonsai/bim/module/nest/prop.py
+++ b/src/bonsai/bonsai/bim/module/nest/prop.py
@@ -32,10 +32,11 @@ from bpy.props import (
     CollectionProperty,
 )
 from bonsai.bim.module.nest.decorator import NestDecorator, NestModeDecorator
+from typing import TYPE_CHECKING, Union
 
 
-def update_relating_object(self, context):
-    def message(self, context):
+def update_relating_object(self: "BIMObjectNestProperties", context: bpy.types.Context) -> None:
+    def message(self, context: bpy.types.Context) -> None:
         self.layout.label(text="Please select a valid Ifc Element")
 
     if self.relating_object is None:
@@ -49,15 +50,19 @@ class BIMObjectNestProperties(PropertyGroup):
     is_editing: BoolProperty(name="Is Editing")
     relating_object: PointerProperty(name="Nest Host", type=bpy.types.Object, update=update_relating_object)
 
+    if TYPE_CHECKING:
+        is_editing: bool
+        relating_object: bpy.types.Object
 
-def update_nest_decorator(self, context):
+
+def update_nest_decorator(self: "BIMNestProperties", context: bpy.types.Context) -> None:
     if self.nest_decorator:
         NestDecorator.install(bpy.context)
     else:
         NestDecorator.uninstall()
 
 
-def update_nest_mode_decorator(self, context):
+def update_nest_mode_decorator(self: "BIMNestProperties", context: bpy.types.Context) -> None:
     if self.in_nest_mode:
         NestModeDecorator.install(bpy.context)
     else:
@@ -68,6 +73,10 @@ class Objects(bpy.types.PropertyGroup):
     obj: PointerProperty(type=bpy.types.Object)
     previous_display_type: bpy.props.StringProperty(default="TEXTURED")
 
+    if TYPE_CHECKING:
+        obj: Union[bpy.types.Object, None]
+        previous_display_type: str
+
 
 class BIMNestProperties(PropertyGroup):
     in_nest_mode: BoolProperty(name="In Edit Mode", update=update_nest_mode_decorator)
@@ -79,3 +88,10 @@ class BIMNestProperties(PropertyGroup):
         default=False,
         update=update_nest_decorator,
     )
+
+    if TYPE_CHECKING:
+        in_nest_mode: bool
+        editing_nest: Union[bpy.types.Object, None]
+        editing_objects: bpy.types.bpy_prop_collection_idprop[Objects]
+        not_editing_objects: bpy.types.bpy_prop_collection_idprop[Objects]
+        nest_decorator: bool
diff --git a/src/bonsai/bonsai/bim/module/nest/ui.py b/src/bonsai/bonsai/bim/module/nest/ui.py
index 601fedf098..2ea33de49a 100644
--- a/src/bonsai/bonsai/bim/module/nest/ui.py
+++ b/src/bonsai/bonsai/bim/module/nest/ui.py
@@ -48,7 +48,8 @@ class BIM_PT_nest(Panel):
         if not NestData.is_loaded:
             NestData.load()
 
-        props = context.active_object.BIMObjectNestProperties
+        assert (obj := context.active_object)
+        props = tool.Nest.get_object_nest_props(obj)
 
         if props.is_editing:
             row = layout.row(align=True)
diff --git a/src/bonsai/bonsai/bim/module/root/operator.py b/src/bonsai/bonsai/bim/module/root/operator.py
index c204200a94..fcc9303fc4 100644
--- a/src/bonsai/bonsai/bim/module/root/operator.py
+++ b/src/bonsai/bonsai/bim/module/root/operator.py
@@ -35,6 +35,7 @@ import bonsai.bim.module.root.prop as root_prop
 from bonsai.bim.ifc import IfcStore
 from bonsai.bim.helper import get_enum_items, prop_with_search
 from mathutils import Vector
+from typing import TYPE_CHECKING
 
 
 class EnableReassignClass(bpy.types.Operator):
@@ -182,6 +183,15 @@ class AssignClass(bpy.types.Operator, tool.Ifc.Operator):
     should_add_representation: bpy.props.BoolProperty(default=True)
     ifc_representation_class: bpy.props.StringProperty()
 
+    if TYPE_CHECKING:
+        obj: str
+        ifc_class: str
+        predefined_type: str
+        userdefined_type: str
+        context_id: int
+        should_add_representation: bool
+        ifc_representation_class: str
+
     def _execute(self, context):
         props = tool.Root.get_root_props()
         objects: list[bpy.types.Object] = []
diff --git a/src/bonsai/bonsai/bim/ui.py b/src/bonsai/bonsai/bim/ui.py
index a6e8d2b25f..e73dab5288 100644
--- a/src/bonsai/bonsai/bim/ui.py
+++ b/src/bonsai/bonsai/bim/ui.py
@@ -1262,8 +1262,8 @@ class BIM_PT_decorators_overlay(Panel):
         overlay = view.overlay
 
         georeference_props = tool.Georeference.get_georeference_props()
-        aggregate_props = bpy.context.scene.BIMAggregateProperties
-        nest_props = bpy.context.scene.BIMNestProperties
+        aggregate_props = tool.Aggregate.get_aggregate_props()
+        nest_props = tool.Nest.get_nest_props()
         model_props = tool.Model.get_model_props()
         display_all = overlay.show_overlays
 
diff --git a/src/bonsai/bonsai/core/nest.py b/src/bonsai/bonsai/core/nest.py
index 45eb660a9d..18fe5c5831 100644
--- a/src/bonsai/bonsai/core/nest.py
+++ b/src/bonsai/bonsai/core/nest.py
@@ -25,15 +25,21 @@ if TYPE_CHECKING:
     import bonsai.tool as tool
 
 
-def enable_editing_nest(nest, obj=None):
+def enable_editing_nest(nest: tool.Nest, obj: bpy.types.Object) -> None:
     nest.enable_editing(obj)
 
 
-def disable_editing_nest(nest, obj=None):
+def disable_editing_nest(nest: tool.Nest, obj: bpy.types.Object) -> None:
     nest.disable_editing(obj)
 
 
-def assign_object(ifc, nest, collector, relating_obj=None, related_obj=None):
+def assign_object(
+    ifc: tool.Ifc,
+    nest: tool.Nest,
+    collector: tool.Collector,
+    relating_obj: bpy.types.Object,
+    related_obj: bpy.types.Object,
+) -> Union[ifcopenshell.entity_instance, None]:
     if not nest.can_nest(relating_obj, related_obj):
         return
     rel = ifc.run(
@@ -47,14 +53,22 @@ def assign_object(ifc, nest, collector, relating_obj=None, related_obj=None):
     return rel
 
 
-def unassign_object(ifc, nest, collector, relating_obj=None, related_obj=None):
+def unassign_object(
+    ifc: tool.Ifc,
+    nest: tool.Nest,
+    collector: tool.Collector,
+    relating_obj: bpy.types.Object,
+    related_obj: bpy.types.Object,
+) -> Union[ifcopenshell.entity_instance, None]:
     related_element = ifc.get_entity(related_obj)
+    assert related_element
     container = nest.get_container(related_element)
+    # TODO: this branch is never used?
     if not relating_obj:
         relating_element = nest.get_relating_object(related_element)
         if related_element:
             relating_obj = ifc.get_object(relating_element)
-    if relating_obj:
+    else:
         ifc.run("nest.unassign_object", related_objects=[related_element])
         if container:
             ifc.run("spatial.assign_container", products=[related_element], relating_structure=container)
@@ -62,21 +76,28 @@ def unassign_object(ifc, nest, collector, relating_obj=None, related_obj=None):
         collector.assign(related_obj)
 
 
-def add_part_to_object(ifc, nest, collector, blender, obj, part_class, part_name=None):
+def add_part_to_object(
+    ifc: tool.Ifc,
+    nest: tool.Nest,
+    collector: tool.Collector,
+    blender: tool.Blender,
+    obj: bpy.types.Object,
+    part_class: str,
+    part_name: str,
+) -> None:
     part_obj = blender.create_ifc_object(ifc_class=part_class, name=part_name)
     assign_object(ifc, nest, collector, relating_obj=obj, related_obj=part_obj)
-    blender.set_active_object(obj)
 
 
 def enable_nest_mode(
     nest: tool.Nest,
     obj: bpy.types.Object,
-):
+) -> None:
     if nest.get_nest_mode():
         disable_nest_mode(nest)
 
     nest.enable_nest_mode(obj)
 
 
-def disable_nest_mode(nest: tool.Nest):
+def disable_nest_mode(nest: tool.Nest) -> None:
     nest.disable_nest_mode()
diff --git a/src/bonsai/bonsai/tool/aggregate.py b/src/bonsai/bonsai/tool/aggregate.py
index d3c0589cea..e2fb4df5f9 100644
--- a/src/bonsai/bonsai/tool/aggregate.py
+++ b/src/bonsai/bonsai/tool/aggregate.py
@@ -16,15 +16,27 @@
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import annotations
 import bpy
 import bonsai.core.tool
 import bonsai.tool as tool
 import ifcopenshell.util.element
 import ifcopenshell.util.representation
-from typing import Union
+from typing import Union, TYPE_CHECKING, Literal
+
+if TYPE_CHECKING:
+    from bonsai.bim.module.aggregate.prop import BIMAggregateProperties, BIMObjectAggregateProperties
 
 
 class Aggregate(bonsai.core.tool.Aggregate):
+    @classmethod
+    def get_aggregate_props(cls) -> BIMAggregateProperties:
+        return bpy.context.scene.BIMAggregateProperties
+
+    @classmethod
+    def get_object_aggregate_props(cls, obj: bpy.types.Object) -> BIMObjectAggregateProperties:
+        return obj.BIMObjectAggregateProperties
+
     @classmethod
     def can_aggregate(cls, relating_obj: bpy.types.Object, related_obj: bpy.types.Object) -> bool:
         relating_object = tool.Ifc.get_entity(relating_obj)
@@ -56,11 +68,13 @@ class Aggregate(bonsai.core.tool.Aggregate):
 
     @classmethod
     def disable_editing(cls, obj: bpy.types.Object) -> None:
-        obj.BIMObjectAggregateProperties.is_editing = False
+        props = cls.get_object_aggregate_props(obj)
+        props.is_editing = False
 
     @classmethod
     def enable_editing(cls, obj: bpy.types.Object) -> None:
-        obj.BIMObjectAggregateProperties.is_editing = True
+        props = cls.get_object_aggregate_props(obj)
+        props.is_editing = True
 
     @classmethod
     def get_container(cls, element: ifcopenshell.entity_instance) -> Union[ifcopenshell.entity_instance, None]:
@@ -86,13 +100,14 @@ class Aggregate(bonsai.core.tool.Aggregate):
         return parts
 
     @classmethod
-    def get_aggregate_mode(cls):
-        return bpy.context.scene.BIMAggregateProperties.in_aggregate_mode
+    def get_aggregate_mode(cls) -> bool:
+        props = cls.get_aggregate_props()
+        return props.in_aggregate_mode
 
     @classmethod
-    def enable_aggregate_mode(cls, active_object: bpy.types.Object):
+    def enable_aggregate_mode(cls, active_object: bpy.types.Object) -> set[Literal["FINISHED"]]:
         context = bpy.context
-        props = context.scene.BIMAggregateProperties
+        props = cls.get_aggregate_props()
 
         element = tool.Ifc.get_entity(active_object)
         if not element:
@@ -131,7 +146,7 @@ class Aggregate(bonsai.core.tool.Aggregate):
     @classmethod
     def disable_aggregate_mode(cls):
         context = bpy.context
-        props = context.scene.BIMAggregateProperties
+        props = cls.get_aggregate_props()
         for obj_prop in props.not_editing_objects:
             obj = obj_prop.obj
             if not obj:
diff --git a/src/bonsai/bonsai/tool/nest.py b/src/bonsai/bonsai/tool/nest.py
index a4f0dc20ec..094299c499 100644
--- a/src/bonsai/bonsai/tool/nest.py
+++ b/src/bonsai/bonsai/tool/nest.py
@@ -16,13 +16,26 @@
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import annotations
 import bpy
 import bonsai.core.tool
 import bonsai.tool as tool
 import ifcopenshell.util.element
+from typing import TYPE_CHECKING, Union
+
+if TYPE_CHECKING:
+    from bonsai.bim.module.nest.prop import BIMNestProperties, BIMObjectNestProperties
 
 
 class Nest(bonsai.core.tool.Nest):
+    @classmethod
+    def get_nest_props(cls) -> BIMNestProperties:
+        return bpy.context.scene.BIMNestProperties
+
+    @classmethod
+    def get_object_nest_props(cls, obj: bpy.types.Object) -> BIMObjectNestProperties:
+        return obj.BIMObjectNestProperties
+
     @classmethod
     def can_nest(cls, relating_obj, related_obj):
         relating_object = tool.Ifc.get_entity(relating_obj)
@@ -34,19 +47,23 @@ class Nest(bonsai.core.tool.Nest):
         return False
 
     @classmethod
-    def disable_editing(cls, obj):
-        obj.BIMObjectNestProperties.is_editing = False
+    def disable_editing(cls, obj: bpy.types.Object) -> None:
+        props = cls.get_object_nest_props(obj)
+        props.is_editing = False
 
     @classmethod
-    def enable_editing(cls, obj):
-        obj.BIMObjectNestProperties.is_editing = True
+    def enable_editing(cls, obj: bpy.types.Object) -> None:
+        props = cls.get_object_nest_props(obj)
+        props.is_editing = True
 
     @classmethod
-    def get_container(cls, element):
+    def get_container(cls, element: ifcopenshell.entity_instance) -> Union[ifcopenshell.entity_instance, None]:
         return ifcopenshell.util.element.get_container(element)
 
     @classmethod
-    def get_relating_object(cls, related_element):
+    def get_relating_object(
+        cls, related_element: ifcopenshell.entity_instance
+    ) -> Union[ifcopenshell.entity_instance, None]:
         return ifcopenshell.util.element.get_nest(related_element)
 
     @classmethod
@@ -61,13 +78,14 @@ class Nest(bonsai.core.tool.Nest):
         return components
 
     @classmethod
-    def get_nest_mode(cls):
-        return bpy.context.scene.BIMNestProperties.in_nest_mode
+    def get_nest_mode(cls) -> bool:
+        props = cls.get_nest_props()
+        return props.in_nest_mode
 
     @classmethod
     def enable_nest_mode(cls, active_object: bpy.types.Object):
         context = bpy.context
-        props = context.scene.BIMNestProperties
+        props = cls.get_nest_props()
 
         element = tool.Ifc.get_entity(active_object)
         if not element:
diff --git a/src/bonsai/bonsai/tool/root.py b/src/bonsai/bonsai/tool/root.py
index 7ce135b730..bb6aa116c0 100644
--- a/src/bonsai/bonsai/tool/root.py
+++ b/src/bonsai/bonsai/tool/root.py
@@ -238,13 +238,13 @@ class Root(bonsai.core.tool.Root):
 
     @classmethod
     def is_in_aggregate_mode(cls, element: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
-        props = bpy.context.scene.BIMAggregateProperties
+        props = tool.Aggregate.get_aggregate_props()
         if props.editing_aggregate and props.in_aggregate_mode:
             return tool.Ifc.get_entity(props.editing_aggregate)
 
     @classmethod
     def is_in_nest_mode(cls, element: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
-        props = bpy.context.scene.BIMNestProperties
+        props = tool.Nest.get_nest_props()
         if props.editing_nest and props.in_nest_mode:
             return tool.Ifc.get_entity(props.editing_nest)
 
diff --git a/src/bonsai/test/tool/test_aggregate.py b/src/bonsai/test/tool/test_aggregate.py
index 0f58f617eb..94130a5661 100644
--- a/src/bonsai/test/tool/test_aggregate.py
+++ b/src/bonsai/test/tool/test_aggregate.py
@@ -122,14 +122,16 @@ class TestDisableEditing(NewFile):
         obj = bpy.data.objects.new("Object", None)
         subject.enable_editing(obj)
         subject.disable_editing(obj)
-        assert obj.BIMObjectAggregateProperties.is_editing is False
+        props = tool.Aggregate.get_object_aggregate_props(obj)
+        assert props.is_editing is False
 
 
 class TestEnableEditing(NewFile):
     def test_run(self):
         obj = bpy.data.objects.new("Object", None)
         subject.enable_editing(obj)
-        assert obj.BIMObjectAggregateProperties.is_editing is True
+        props = tool.Aggregate.get_object_aggregate_props(obj)
+        assert props.is_editing is True
 
 
 class TestGetContainer(NewFile):
diff --git a/src/bonsai/test/tool/test_nest.py b/src/bonsai/test/tool/test_nest.py
index c68f5ae692..c9499e40de 100644
--- a/src/bonsai/test/tool/test_nest.py
+++ b/src/bonsai/test/tool/test_nest.py
@@ -54,14 +54,16 @@ class TestDisableEditing(NewFile):
         obj = bpy.data.objects.new("Object", None)
         subject.enable_editing(obj)
         subject.disable_editing(obj)
-        assert obj.BIMObjectNestProperties.is_editing is False
+        props = tool.Nest.get_object_nest_props(obj)
+        assert props.is_editing is False
 
 
 class TestEnableEditing(NewFile):
     def test_run(self):
         obj = bpy.data.objects.new("Object", None)
         subject.enable_editing(obj)
-        assert obj.BIMObjectNestProperties.is_editing is True
+        props = tool.Nest.get_object_nest_props(obj)
+        assert props.is_editing is True
 
 
 class TestGetContainer(NewFile):
diff --git a/src/ifcopenshell-python/ifcopenshell/api/geometry/add_representation.py b/src/ifcopenshell-python/ifcopenshell/api/geometry/add_representation.py
index 8244c3e434..d6d729d8aa 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/geometry/add_representation.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/geometry/add_representation.py
@@ -112,15 +112,15 @@ class Usecase:
     ifc_vertices: list[ifcopenshell.entity_instance]
     coordinate_offset: Union[npt.NDArray[np.float64], None]
     geometry: Union[bpy.types.Mesh, bpy.types.Curve]
+    blender_object: bpy.types.Object
 
     def execute(self) -> Union[ifcopenshell.entity_instance, None]:
         self.is_manifold = None
         self.coordinate_offset = self.settings["coordinate_offset"]
         self.geometry = self.settings["geometry"]
-        if (
-            isinstance(self.settings["geometry"], bpy.types.Mesh)
-            and self.settings["geometry"] == self.settings["blender_object"].data
-        ):
+        self.blender_object = self.settings["blender_object"]
+
+        if isinstance(self.geometry, bpy.types.Mesh) and self.geometry == self.blender_object.data:
             self.evaluate_geometry()
         if self.settings["unit_scale"] is None:
             self.settings["unit_scale"] = ifcopenshell.util.unit.calculate_unit_scale(self.file)
@@ -147,11 +147,11 @@ class Usecase:
         return any([abs((tM @ v.co).z) > threshold for v in face.verts])
 
     def evaluate_geometry(self) -> None:
-        for modifier in self.settings["blender_object"].modifiers:
+        for modifier in self.blender_object.modifiers:
             if modifier.type == "BOOLEAN":
                 modifier.show_viewport = False
 
-        mesh = self.settings["blender_object"].evaluated_get(bpy.context.evaluated_depsgraph_get()).to_mesh()
+        mesh = self.blender_object.evaluated_get(bpy.context.evaluated_depsgraph_get()).to_mesh()
         bm = bmesh.new()
         bm.from_mesh(mesh)
 
@@ -173,7 +173,7 @@ class Usecase:
 
         self.settings["geometry"] = mesh
 
-        for modifier in self.settings["blender_object"].modifiers:
+        for modifier in self.blender_object.modifiers:
             if modifier.type == "BOOLEAN":
                 modifier.show_viewport = True
 
@@ -540,7 +540,7 @@ class Usecase:
 
         # create dummy object that will have more detailed curves
         # since now we do not really support splines curves natively
-        obj = self.settings["blender_object"]
+        obj = self.blender_object
         dummy = bpy.data.objects.new("Dummy", obj.data.copy())
         bpy.context.scene.collection.objects.link(dummy)
         tool.Blender.select_and_activate_single_object(bpy.context, dummy)
@@ -752,7 +752,7 @@ class Usecase:
             profile_def,
             position,
             self.file.createIfcDirection((0.0, 0.0, 1.0)),
-            self.convert_si_to_unit(self.settings["blender_object"].dimensions[2]),
+            self.convert_si_to_unit(self.blender_object.dimensions[2]),
         )
         return self.file.createIfcShapeRepresentation(
             self.settings["context"],
@@ -952,7 +952,7 @@ class Usecase:
         )
 
     def create_box_representation(self) -> ifcopenshell.entity_instance:
-        obj = self.settings["blender_object"]
+        obj = self.blender_object
         bounding_box = self.file.createIfcBoundingBox(
             self.create_cartesian_point(obj.bound_box[0][0], obj.bound_box[0][1], obj.bound_box[0][2]),
             self.convert_si_to_unit(obj.dimensions[0]),