diff --git a/src/blenderbim/blenderbim/bim/export_ifc.py b/src/blenderbim/blenderbim/bim/export_ifc.py
index 111da2be9c..8997d7f81e 100644
--- a/src/blenderbim/blenderbim/bim/export_ifc.py
+++ b/src/blenderbim/blenderbim/bim/export_ifc.py
@@ -35,6 +35,7 @@ import blenderbim.core.spatial
 import blenderbim.core.style
 from blenderbim.bim.ifc import IfcStore
 from mathutils import Vector
+from typing import Union
 
 
 class IfcExporter:
@@ -86,8 +87,8 @@ class IfcExporter:
             self.get_application_name(), tool.Blender.get_blenderbim_version()
         )
 
-    def sync_all_objects(self):
-        results = []
+    def sync_all_objects(self) -> list[ifcopenshell.entity_instance]:
+        results: list[ifcopenshell.entity_instance] = []
         self.unit_scale = ifcopenshell.util.unit.calculate_unit_scale(self.file)
         for ifc_definition_id in list(IfcStore.id_map.keys()):
             obj = IfcStore.id_map[ifc_definition_id]
@@ -107,8 +108,8 @@ class IfcExporter:
                 pass  # The object is likely deleted
         return results
 
-    def sync_edited_objects(self):
-        results = []
+    def sync_edited_objects(self) -> list[ifcopenshell.entity_instance]:
+        results: list[ifcopenshell.entity_instance] = []
         for obj in IfcStore.edited_objs.copy():
             if not obj:
                 continue
@@ -126,7 +127,7 @@ class IfcExporter:
         IfcStore.edited_objs.clear()
         return results
 
-    def sync_object_material(self, obj):
+    def sync_object_material(self, obj: bpy.types.Object) -> None:
         if not obj.data or not isinstance(obj.data, bpy.types.Mesh):
             return
         if not self.has_changed_materials(obj):
@@ -137,7 +138,7 @@ class IfcExporter:
         checksum = obj.data.BIMMeshProperties.material_checksum
         return checksum != str([s.id() for s in tool.Geometry.get_styles(obj) if s])
 
-    def sync_object_placement(self, obj):
+    def sync_object_placement(self, obj: bpy.types.Object) -> Union[ifcopenshell.entity_instance, None]:
         element = self.file.by_id(obj.BIMObjectProperties.ifc_definition_id)
         if not tool.Ifc.is_moved(obj):
             return
@@ -152,7 +153,7 @@ class IfcExporter:
         blenderbim.core.geometry.edit_object_placement(tool.Ifc, tool.Geometry, tool.Surveyor, obj=obj)
         return element
 
-    def sync_grid_axis_object_placement(self, obj, element):
+    def sync_grid_axis_object_placement(self, obj: bpy.types.Object, element: ifcopenshell.entity_instance) -> None:
         grid = (element.PartOfU or element.PartOfV or element.PartOfW)[0]
         grid_obj = tool.Ifc.get_object(grid)
         if grid_obj:
diff --git a/src/blenderbim/blenderbim/bim/module/drawing/operator.py b/src/blenderbim/blenderbim/bim/module/drawing/operator.py
index 2849becbd4..ee3d3eeddb 100644
--- a/src/blenderbim/blenderbim/bim/module/drawing/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/drawing/operator.py
@@ -44,7 +44,7 @@ import blenderbim.bim.module.drawing.helper as helper
 import blenderbim.bim.export_ifc
 from blenderbim.bim.module.drawing.decoration import CutDecorator
 from blenderbim.bim.module.drawing.data import DecoratorData, DrawingsData
-from typing import NamedTuple, List, Union
+from typing import NamedTuple, List, Union, Optional
 from lxml import etree
 from mathutils import Vector, Color, Matrix
 from timeit import default_timer as timer
@@ -445,8 +445,14 @@ class CreateDrawing(bpy.types.Operator):
         return LineworkContexts(body_contexts, annotation_contexts)
 
     def serialize_contexts_elements(
-        self, ifc, tree: ifcopenshell.geom.tree, contexts: LineworkContexts, context_type, drawing_elements, target_view
-    ):
+        self,
+        ifc: ifcopenshell.file,
+        tree: ifcopenshell.geom.tree,
+        contexts: LineworkContexts,
+        context_type: str,
+        drawing_elements: set[ifcopenshell.entity_instance],
+        target_view: str,
+    ) -> None:
         drawing_elements = drawing_elements.copy()
         contexts = getattr(contexts, context_type)
         for context in contexts:
@@ -472,7 +478,7 @@ class CreateDrawing(bpy.types.Operator):
                     tree.add_element(elem)
                 drawing_elements -= processed
 
-    def generate_linework(self, context):
+    def generate_linework(self, context: bpy.types.Context) -> Union[str, None]:
         if not ifcopenshell.util.element.get_pset(self.drawing, "EPset_Drawing", "HasLinework"):
             return
         svg_path = self.get_svg_path(cache_type="linework")
@@ -1115,14 +1121,14 @@ class CreateDrawing(bpy.types.Operator):
                     continue
                 return space
 
-    def get_material_name(self, element):
+    def get_material_name(self, element: ifcopenshell.entity_instance) -> str:
         if hasattr(element, "Name") and element.Name:
             return element.Name
         elif hasattr(element, "LayerSetName") and element.LayerSetName:
             return element.LayerSetName
         return "mat-" + str(element.id())
 
-    def get_svg_path(self, cache_type=None):
+    def get_svg_path(self, cache_type: Optional[str] = None) -> str:
         drawing_path = tool.Drawing.get_document_uri(self.camera_document)
         drawings_dir = os.path.dirname(drawing_path)
 
diff --git a/src/blenderbim/blenderbim/core/geometry.py b/src/blenderbim/blenderbim/core/geometry.py
index 8677152284..88a97eff6e 100644
--- a/src/blenderbim/blenderbim/core/geometry.py
+++ b/src/blenderbim/blenderbim/core/geometry.py
@@ -16,10 +16,18 @@
 # You should have received a copy of the GNU General Public License
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import annotations
 import blenderbim.core.style
+from typing import TYPE_CHECKING, Optional
+import blenderbim.core.tool as tool
+
+if TYPE_CHECKING:
+    import bpy
 
 
-def edit_object_placement(ifc, geometry, surveyor, obj=None):
+def edit_object_placement(
+    ifc: tool.Ifc, geometry: tool.Geometry, surveyor: tool.Surveyor, obj: Optional[bpy.types.Object] = None
+) -> None:
     element = ifc.get_entity(obj)
     if not element:
         return
diff --git a/src/blenderbim/blenderbim/core/spatial.py b/src/blenderbim/blenderbim/core/spatial.py
index 8121674193..8e37c5650d 100644
--- a/src/blenderbim/blenderbim/core/spatial.py
+++ b/src/blenderbim/blenderbim/core/spatial.py
@@ -16,18 +16,42 @@
 # You should have received a copy of the GNU General Public License
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import annotations
+from typing import TYPE_CHECKING, Optional, Union
+import blenderbim.core.tool as tool
 
-def reference_structure(ifc, spatial, structure=None, element=None):
+if TYPE_CHECKING:
+    import bpy
+    import ifcopenshell
+
+
+def reference_structure(
+    ifc: tool.Ifc,
+    spatial: tool.Spatial,
+    structure: Optional[ifcopenshell.entity_instance] = None,
+    element: Optional[ifcopenshell.entity_instance] = None,
+) -> Union[ifcopenshell.entity_instance, None]:
     if spatial.can_reference(structure, element):
         return ifc.run("spatial.reference_structure", product=element, relating_structure=structure)
 
 
-def dereference_structure(ifc, spatial, structure=None, element=None):
+def dereference_structure(
+    ifc: tool.Ifc,
+    spatial: tool.Spatial,
+    structure: Optional[ifcopenshell.entity_instance] = None,
+    element: Optional[ifcopenshell.entity_instance] = None,
+) -> None:
     if spatial.can_reference(structure, element):
         return ifc.run("spatial.dereference_structure", product=element, relating_structure=structure)
 
 
-def assign_container(ifc, collector, spatial, structure_obj=None, element_obj=None):
+def assign_container(
+    ifc: tool.Ifc,
+    collector: tool.Collector,
+    spatial: tool.Spatial,
+    structure_obj: Optional[bpy.types.Object] = None,
+    element_obj: Optional[bpy.types.Object] = None,
+) -> Union[ifcopenshell.entity_instance, None]:
     if not spatial.can_contain(structure_obj, element_obj):
         return
     rel = ifc.run(
diff --git a/src/blenderbim/blenderbim/tool/collector.py b/src/blenderbim/blenderbim/tool/collector.py
index ed4e9377f5..e834cbc492 100644
--- a/src/blenderbim/blenderbim/tool/collector.py
+++ b/src/blenderbim/blenderbim/tool/collector.py
@@ -20,6 +20,8 @@ import bpy
 import ifcopenshell.util.element
 
 import blenderbim.core.tool
+import blenderbim.core.spatial
+import blenderbim.core.aggregate
 import blenderbim.tool as tool
 from typing import Union
 
diff --git a/src/blenderbim/blenderbim/tool/spatial.py b/src/blenderbim/blenderbim/tool/spatial.py
index 2a9c3d1fd1..1f72007547 100644
--- a/src/blenderbim/blenderbim/tool/spatial.py
+++ b/src/blenderbim/blenderbim/tool/spatial.py
@@ -34,7 +34,7 @@ from shapely import Polygon, MultiPolygon
 
 class Spatial(blenderbim.core.tool.Spatial):
     @classmethod
-    def can_contain(cls, structure_obj, element_obj):
+    def can_contain(cls, structure_obj: bpy.types.Object, element_obj: bpy.types.Object) -> bool:
         structure = tool.Ifc.get_entity(structure_obj)
         element = tool.Ifc.get_entity(element_obj)
         if not structure or not element:
@@ -52,7 +52,7 @@ class Spatial(blenderbim.core.tool.Spatial):
         return True
 
     @classmethod
-    def can_reference(cls, structure, element):
+    def can_reference(cls, structure: ifcopenshell.entity_instance, element: ifcopenshell.entity_instance) -> bool:
         if not structure or not element:
             return False
         if tool.Ifc.get_schema() == "IFC2X3":