diff --git a/src/bonsai/bonsai/bim/import_ifc.py b/src/bonsai/bonsai/bim/import_ifc.py
index 8747f28891..1332258c12 100644
--- a/src/bonsai/bonsai/bim/import_ifc.py
+++ b/src/bonsai/bonsai/bim/import_ifc.py
@@ -1033,7 +1033,7 @@ class IfcImporter:
         element: ifcopenshell.entity_instance,
         shape: Union[ifcopenshell.geom.ShapeElementType, ifcopenshell.geom.ShapeType],
     ) -> bpy.types.Curve:
-        if hasattr(shape, "geometry"):
+        if isinstance(shape, ifcopenshell.geom.ShapeElementType):
             geometry = shape.geometry
         else:
             geometry = shape
@@ -1066,7 +1066,7 @@ class IfcImporter:
         cartesian_point_offset: Union[npt.NDArray[np.float64], Literal[False]] = None,
     ) -> Union[bpy.types.Mesh, None]:
         try:
-            if hasattr(shape, "geometry"):
+            if isinstance(shape, ifcopenshell.geom.ShapeElementType):
                 # shape is ShapeElementType
                 geometry = shape.geometry
             else:
diff --git a/src/bonsai/bonsai/bim/module/constraint/operator.py b/src/bonsai/bonsai/bim/module/constraint/operator.py
index 4ae0dde395..5b291106f8 100644
--- a/src/bonsai/bonsai/bim/module/constraint/operator.py
+++ b/src/bonsai/bonsai/bim/module/constraint/operator.py
@@ -17,12 +17,27 @@
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
 import bpy
-import json
 import ifcopenshell.api
 import ifcopenshell.api.constraint
-import ifcopenshell.util.attribute
 import bonsai.bim.helper
 import bonsai.tool as tool
+from typing import TYPE_CHECKING
+
+
+def get_active_object(context: bpy.types.Context, obj_name: str) -> bpy.types.Object:
+    if obj_name:
+        obj = bpy.data.objects[obj_name]
+    else:
+        assert (obj := context.active_object)
+    return obj
+
+
+def get_selected_objects(context: bpy.types.Context, obj_name: str) -> list[bpy.types.Object]:
+    if obj_name:
+        objs = [bpy.data.objects[obj_name]]
+    else:
+        objs = context.selected_objects
+    return objs
 
 
 class LoadObjectives(bpy.types.Operator):
@@ -31,7 +46,7 @@ class LoadObjectives(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def execute(self, context):
-        props = context.scene.BIMConstraintProperties
+        props = tool.Blender.get_constraint_props()
         props.constraints.clear()
         for constraint in tool.Ifc.get().by_type("IfcObjective"):
             new = props.constraints.add()
@@ -48,7 +63,8 @@ class DisableConstraintEditingUI(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def execute(self, context):
-        context.scene.BIMConstraintProperties.is_editing = ""
+        props = tool.Blender.get_constraint_props()
+        props.is_editing = ""
         bpy.ops.bim.disable_editing_constraint()
         return {"FINISHED"}
 
@@ -59,8 +75,11 @@ class EnableEditingConstraint(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
     constraint: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        constraint: int
+
     def execute(self, context):
-        props = context.scene.BIMConstraintProperties
+        props = tool.Blender.get_constraint_props()
         props.constraint_attributes.clear()
         bonsai.bim.helper.import_attributes2(tool.Ifc.get().by_id(self.constraint), props.constraint_attributes)
         props.active_constraint_id = self.constraint
@@ -73,7 +92,8 @@ class DisableEditingConstraint(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def execute(self, context):
-        context.scene.BIMConstraintProperties.active_constraint_id = 0
+        props = tool.Blender.get_constraint_props()
+        props.active_constraint_id = 0
         return {"FINISHED"}
 
 
@@ -83,7 +103,7 @@ class AddObjective(bpy.types.Operator, tool.Ifc.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def _execute(self, context):
-        result = ifcopenshell.api.run("constraint.add_objective", tool.Ifc.get())
+        result = ifcopenshell.api.constraint.add_objective(tool.Ifc.get())
         bpy.ops.bim.load_objectives()
         bpy.ops.bim.enable_editing_constraint(constraint=result.id())
         return {"FINISHED"}
@@ -95,7 +115,7 @@ class EditObjective(bpy.types.Operator, tool.Ifc.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def _execute(self, context):
-        props = context.scene.BIMConstraintProperties
+        props = tool.Blender.get_constraint_props()
         attributes = bonsai.bim.helper.export_attributes(props.constraint_attributes)
         ifc_file = tool.Ifc.get()
         ifcopenshell.api.constraint.edit_objective(
@@ -113,12 +133,13 @@ class RemoveConstraint(bpy.types.Operator, tool.Ifc.Operator):
     bl_options = {"REGISTER", "UNDO"}
     constraint: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        constraint: int
+
     def _execute(self, context):
-        props = context.scene.BIMConstraintProperties
+        props = tool.Blender.get_constraint_props()
         self.file = tool.Ifc.get()
-        ifcopenshell.api.run(
-            "constraint.remove_constraint", self.file, **{"constraint": self.file.by_id(self.constraint)}
-        )
+        ifcopenshell.api.constraint.remove_constraint(self.file, constraint=self.file.by_id(self.constraint))
         if props.is_editing == "IfcObjective":
             bpy.ops.bim.load_objectives()
         return {"FINISHED"}
@@ -130,9 +151,12 @@ class EnableAssigningConstraint(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
     obj: bpy.props.StringProperty()
 
+    if TYPE_CHECKING:
+        obj: str
+
     def execute(self, context):
-        obj = bpy.data.objects.get(self.obj) if self.obj else context.active_object
-        props = obj.BIMObjectConstraintProperties
+        obj = get_active_object(context, self.obj)
+        props = tool.Blender.get_object_constraint_props(obj)
         if props.available_constraint_types == "IfcObjective":
             bpy.ops.bim.load_objectives()
         props.is_adding = props.available_constraint_types
@@ -145,9 +169,12 @@ class DisableAssigningConstraint(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
     obj: bpy.props.StringProperty()
 
+    if TYPE_CHECKING:
+        obj: str
+
     def execute(self, context):
-        obj = bpy.data.objects.get(self.obj) if self.obj else context.active_object
-        props = obj.BIMObjectConstraintProperties
+        obj = get_active_object(context, self.obj)
+        props = tool.Blender.get_object_constraint_props(obj)
         props.is_adding = ""
         return {"FINISHED"}
 
@@ -159,8 +186,13 @@ class AssignConstraint(bpy.types.Operator, tool.Ifc.Operator):
     obj: bpy.props.StringProperty()
     constraint: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        obj: str
+        constraint: int
+
     def _execute(self, context):
         self.file = tool.Ifc.get()
+        objs = get_selected_objects(context, self.obj)
         objs = [bpy.data.objects[self.obj]] if self.obj else context.selected_objects
         products = [
             self.file.by_id(obj_id)
@@ -168,13 +200,10 @@ class AssignConstraint(bpy.types.Operator, tool.Ifc.Operator):
             if (obj_id := tool.Blender.get_object_bim_props(obj).ifc_definition_id)
         ]
         if products:
-            ifcopenshell.api.run(
-                "constraint.assign_constraint",
+            ifcopenshell.api.constraint.assign_constraint(
                 self.file,
-                **{
-                    "products": products,
-                    "constraint": self.file.by_id(self.constraint),
-                },
+                products=products,
+                constraint=self.file.by_id(self.constraint),
             )
         return {"FINISHED"}
 
@@ -186,21 +215,22 @@ class UnassignConstraint(bpy.types.Operator, tool.Ifc.Operator):
     obj: bpy.props.StringProperty()
     constraint: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        obj: str
+        constraint: int
+
     def _execute(self, context):
         self.file = tool.Ifc.get()
-        objs = [bpy.data.objects[self.obj]] if self.obj else context.selected_objects
+        objs = get_selected_objects(context, self.obj)
         products = [
             self.file.by_id(obj_id)
             for obj in objs
             if (obj_id := tool.Blender.get_object_bim_props(obj).ifc_definition_id)
         ]
         if products:
-            ifcopenshell.api.run(
-                "constraint.unassign_constraint",
+            ifcopenshell.api.constraint.unassign_constraint(
                 self.file,
-                **{
-                    "products": products,
-                    "constraint": self.file.by_id(self.constraint),
-                },
+                products=products,
+                constraint=self.file.by_id(self.constraint),
             )
         return {"FINISHED"}
diff --git a/src/bonsai/bonsai/bim/module/constraint/prop.py b/src/bonsai/bonsai/bim/module/constraint/prop.py
index b773af506a..ec66f78211 100644
--- a/src/bonsai/bonsai/bim/module/constraint/prop.py
+++ b/src/bonsai/bonsai/bim/module/constraint/prop.py
@@ -32,6 +32,7 @@ from bpy.props import (
     FloatVectorProperty,
     CollectionProperty,
 )
+from typing import TYPE_CHECKING, Literal
 
 
 def get_available_constraint_types(self, context):
@@ -44,6 +45,10 @@ class Constraint(PropertyGroup):
     name: StringProperty(name="Name")
     ifc_definition_id: IntProperty(name="IFC Definition ID")
 
+    if TYPE_CHECKING:
+        name: str
+        ifc_definition_id: int
+
 
 class BIMConstraintProperties(PropertyGroup):
     constraint_attributes: CollectionProperty(name="Constraint Attributes", type=Attribute)
@@ -52,7 +57,18 @@ class BIMConstraintProperties(PropertyGroup):
     active_constraint_index: IntProperty(name="Active Constraint Index")
     is_editing: StringProperty(name="Is Editing")
 
+    if TYPE_CHECKING:
+        constraint_attributes: bpy.types.bpy_prop_collection_idprop[Attribute]
+        active_constraint_id: int
+        constraints: bpy.types.bpy_prop_collection_idprop[Constraint]
+        active_constraint_index: int
+        is_editing: str
+
 
 class BIMObjectConstraintProperties(PropertyGroup):
     is_adding: StringProperty(name="Is Adding")
     available_constraint_types: EnumProperty(items=get_available_constraint_types, name="Available Constraint Types")
+
+    if TYPE_CHECKING:
+        is_adding: str
+        available_constraint_types: Literal["IfcObjective"]
diff --git a/src/bonsai/bonsai/bim/module/constraint/ui.py b/src/bonsai/bonsai/bim/module/constraint/ui.py
index 3693e9565a..61b335d782 100644
--- a/src/bonsai/bonsai/bim/module/constraint/ui.py
+++ b/src/bonsai/bonsai/bim/module/constraint/ui.py
@@ -16,10 +16,15 @@
 # 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 bonsai.tool as tool
 from bpy.types import Panel, UIList
 from bonsai.bim.helper import draw_attributes
 from bonsai.bim.module.constraint.data import ConstraintsData, ObjectConstraintsData
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from bonsai.bim.module.constraint.prop import BIMConstraintProperties, BIMObjectConstraintProperties, Constraint
 
 
 class BIM_PT_constraints(Panel):
@@ -39,7 +44,7 @@ class BIM_PT_constraints(Panel):
         if not ConstraintsData.is_loaded:
             ConstraintsData.load()
 
-        self.props = context.scene.BIMConstraintProperties
+        self.props = tool.Blender.get_constraint_props()
 
         if not self.props.is_editing or self.props.is_editing == "IfcObjective":
             row = self.layout.row(align=True)
@@ -91,8 +96,8 @@ class BIM_PT_object_constraints(Panel):
         obj = context.active_object
         assert obj
         self.oprops = tool.Blender.get_object_bim_props(obj)
-        self.sprops = context.scene.BIMConstraintProperties
-        self.props = obj.BIMObjectConstraintProperties
+        self.sprops = tool.Blender.get_constraint_props()
+        self.props = tool.Blender.get_object_constraint_props(obj)
         self.file = tool.Ifc.get()
 
         self.draw_add_ui()
@@ -131,15 +136,24 @@ class BIM_PT_object_constraints(Panel):
 
 
 class BIM_UL_constraints(UIList):
-    def draw_item(self, context, layout, data, item, icon, active_data, active_propname):
+    def draw_item(
+        self,
+        context,
+        layout,
+        data: BIMConstraintProperties,
+        item: Constraint,
+        icon,
+        active_data,
+        active_propname,
+    ):
         if item:
             row = layout.row(align=True)
             row.label(text=item.name)
-            if context.scene.BIMConstraintProperties.active_constraint_id == item.ifc_definition_id:
-                if context.scene.BIMConstraintProperties.is_editing == "IfcObjective":
+            if data.active_constraint_id == item.ifc_definition_id:
+                if data.is_editing == "IfcObjective":
                     row.operator("bim.edit_objective", text="", icon="CHECKMARK")
                 row.operator("bim.disable_editing_constraint", text="", icon="CANCEL")
-            elif context.scene.BIMConstraintProperties.active_constraint_id:
+            elif data.active_constraint_id:
                 row.operator("bim.remove_constraint", text="", icon="X").constraint = item.ifc_definition_id
             else:
                 op = row.operator("bim.enable_editing_constraint", text="", icon="GREASEPENCIL")
@@ -148,7 +162,16 @@ class BIM_UL_constraints(UIList):
 
 
 class BIM_UL_object_constraints(UIList):
-    def draw_item(self, context, layout, data, item, icon, active_data, active_propname):
+    def draw_item(
+        self,
+        context,
+        layout,
+        data: BIMObjectConstraintProperties,
+        item: Constraint,
+        icon,
+        active_data,
+        active_propname,
+    ):
         if item:
             row = layout.row(align=True)
             row.label(text=item.name)
diff --git a/src/bonsai/bonsai/bim/module/layer/operator.py b/src/bonsai/bonsai/bim/module/layer/operator.py
index 5480c86034..079c5477f6 100644
--- a/src/bonsai/bonsai/bim/module/layer/operator.py
+++ b/src/bonsai/bonsai/bim/module/layer/operator.py
@@ -17,13 +17,21 @@
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
 import bpy
-import json
 import ifcopenshell.api
 import ifcopenshell.api.layer
 import ifcopenshell.util.element
-import ifcopenshell.util.attribute
 import bonsai.bim.helper
 import bonsai.tool as tool
+from typing import TYPE_CHECKING
+
+
+def get_active_mesh(context: bpy.types.Context, mesh_name: str) -> bpy.types.Mesh:
+    if mesh_name:
+        item_mesh = bpy.data.meshes[mesh_name]
+    else:
+        assert (obj := context.active_object)
+        assert isinstance(item_mesh := obj.data, bpy.types.Mesh)
+    return item_mesh
 
 
 class LoadLayers(bpy.types.Operator):
@@ -32,10 +40,10 @@ class LoadLayers(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def execute(self, context):
-        self.file = tool.Ifc.get()
-        props = context.scene.BIMLayerProperties
+        ifc_file = tool.Ifc.get()
+        props = tool.Layer.get_layer_props()
         props.layers.clear()
-        for layer in tool.Ifc.get().by_type("IfcPresentationLayerAssignment"):
+        for layer in ifc_file.by_type("IfcPresentationLayerAssignment"):
             new = props.layers.add()
             new.name = layer.Name or "Unnamed"
             new.ifc_definition_id = layer.id()
@@ -57,7 +65,8 @@ class DisableLayerEditingUI(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def execute(self, context):
-        context.scene.BIMLayerProperties.is_editing = False
+        props = tool.Layer.get_layer_props()
+        props.is_editing = False
         return {"FINISHED"}
 
 
@@ -67,8 +76,11 @@ class EnableEditingLayer(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
     layer: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        layer: int
+
     def execute(self, context):
-        props = context.scene.BIMLayerProperties
+        props = tool.Layer.get_layer_props()
         props.layer_attributes.clear()
         bonsai.bim.helper.import_attributes2(tool.Ifc.get().by_id(self.layer), props.layer_attributes)
         props.active_layer_id = self.layer
@@ -81,7 +93,8 @@ class DisableEditingLayer(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def execute(self, context):
-        context.scene.BIMLayerProperties.active_layer_id = 0
+        props = tool.Layer.get_layer_props()
+        props.active_layer_id = 0
         return {"FINISHED"}
 
 
@@ -92,7 +105,7 @@ class AddPresentationLayer(bpy.types.Operator, tool.Ifc.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def _execute(self, context):
-        props = context.scene.BIMLayerProperties
+        props = tool.Layer.get_layer_props()
         ifc_file = tool.Ifc.get()
         if props.layer_type == "IfcPresentationLayerWithStyle":
             layer = ifcopenshell.api.layer.add_layer_with_style(ifc_file)
@@ -109,7 +122,7 @@ class EditPresentationLayer(bpy.types.Operator, tool.Ifc.Operator):
     bl_options = {"REGISTER", "UNDO"}
 
     def _execute(self, context):
-        props = context.scene.BIMLayerProperties
+        props = tool.Layer.get_layer_props()
         attributes = bonsai.bim.helper.export_attributes(props.layer_attributes)
         ifc_file = tool.Ifc.get()
         ifcopenshell.api.layer.edit_layer(ifc_file, layer=ifc_file.by_id(props.active_layer_id), attributes=attributes)
@@ -123,10 +136,12 @@ class RemovePresentationLayer(bpy.types.Operator, tool.Ifc.Operator):
     bl_options = {"REGISTER", "UNDO"}
     layer: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        layer: int
+
     def _execute(self, context):
-        props = context.scene.BIMLayerProperties
-        self.file = tool.Ifc.get()
-        ifcopenshell.api.run("layer.remove_layer", self.file, **{"layer": self.file.by_id(self.layer)})
+        ifc_file = tool.Ifc.get()
+        ifcopenshell.api.layer.remove_layer(ifc_file, layer=ifc_file.by_id(self.layer))
         bpy.ops.bim.load_layers()
         return {"FINISHED"}
 
@@ -139,16 +154,17 @@ class AssignPresentationLayer(bpy.types.Operator, tool.Ifc.Operator):
     item: bpy.props.StringProperty()
     layer: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        item: str
+        layer: int
+
     def _execute(self, context):
-        item = bpy.data.meshes.get(self.item) if self.item else context.active_object.data
-        self.file = tool.Ifc.get()
-        ifcopenshell.api.run(
-            "layer.assign_layer",
-            self.file,
-            **{
-                "items": [self.file.by_id(tool.Geometry.get_mesh_props(item).ifc_definition_id)],
-                "layer": self.file.by_id(self.layer),
-            },
+        item = get_active_mesh(context, self.item)
+        ifc_file = tool.Ifc.get()
+        ifcopenshell.api.layer.assign_layer(
+            ifc_file,
+            items=[ifc_file.by_id(tool.Geometry.get_mesh_props(item).ifc_definition_id)],
+            layer=ifc_file.by_id(self.layer),
         )
         return {"FINISHED"}
 
@@ -161,8 +177,12 @@ class UnassignPresentationLayer(bpy.types.Operator, tool.Ifc.Operator):
     item: bpy.props.StringProperty()
     layer: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        item: str
+        layer: int
+
     def _execute(self, context):
-        item = bpy.data.meshes.get(self.item) if self.item else context.active_object.data
+        item = get_active_mesh(context, self.item)
         ifc_file = tool.Ifc.get()
         representation = tool.Geometry.get_data_representation(item)
         assert representation
@@ -176,6 +196,9 @@ class SelectLayerProducts(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
     layer: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        layer: int
+
     def execute(self, context):
         elements = ifcopenshell.util.element.get_elements_by_layer(tool.Ifc.get(), tool.Ifc.get().by_id(self.layer))
         for obj in context.visible_objects:
@@ -192,6 +215,9 @@ class SelectLayerInLayerUI(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
     layer_id: bpy.props.IntProperty()
 
+    if TYPE_CHECKING:
+        layer_id: int
+
     def execute(self, context):
         props = tool.Layer.get_layer_props()
         ifc_file = tool.Ifc.get()
diff --git a/src/bonsai/bonsai/bim/module/layer/prop.py b/src/bonsai/bonsai/bim/module/layer/prop.py
index 6f0dbd7c9c..079ba262de 100644
--- a/src/bonsai/bonsai/bim/module/layer/prop.py
+++ b/src/bonsai/bonsai/bim/module/layer/prop.py
@@ -59,6 +59,14 @@ class Layer(PropertyGroup):
         update=lambda self, context: update_layer_property(self, context, property="blocked"),
     )
 
+    if TYPE_CHECKING:
+        name: str
+        ifc_definition_id: int
+        with_style: bool
+        on: bool
+        frozen: bool
+        blocked: bool
+
 
 class BIMLayerProperties(PropertyGroup):
     layer_attributes: CollectionProperty(name="Layer Attributes", type=Attribute)
diff --git a/src/bonsai/bonsai/bim/module/layer/ui.py b/src/bonsai/bonsai/bim/module/layer/ui.py
index 609cb62815..d7fcdec215 100644
--- a/src/bonsai/bonsai/bim/module/layer/ui.py
+++ b/src/bonsai/bonsai/bim/module/layer/ui.py
@@ -16,11 +16,16 @@
 # 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.tool as tool
 from bpy.types import Panel, UIList, Mesh
 from bonsai.bim.helper import draw_attributes
 from bonsai.bim.module.layer.data import LayersData
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from bonsai.bim.module.layer.prop import BIMLayerProperties, Layer
 
 
 class BIM_PT_layers(Panel):
@@ -40,7 +45,7 @@ class BIM_PT_layers(Panel):
         if not LayersData.is_loaded:
             LayersData.load()
 
-        self.props = context.scene.BIMLayerProperties
+        self.props = tool.Layer.get_layer_props()
 
         row = self.layout.row(align=True)
         row.label(text=f"{LayersData.data['total_layers']} Layers Found", icon="STICKY_UVS_LOC")
@@ -71,7 +76,16 @@ class BIM_PT_layers(Panel):
 
 
 class BIM_UL_layers(UIList):
-    def draw_item(self, context, layout, data, item, icon, active_data, active_propname):
+    def draw_item(
+        self,
+        context: bpy.types.Context,
+        layout: bpy.types.UILayout,
+        data: BIMLayerProperties,
+        item: Layer,
+        icon,
+        active_data,
+        active_propname,
+    ):
         if item:
             row = layout.row(align=True)
             row.label(text=item.name)
@@ -89,12 +103,12 @@ class BIM_UL_layers(UIList):
                 row.prop(item, "frozen", text="", icon="FREEZE" if item.frozen else "MESH_PLANE", emboss=False)
                 row.prop(item, "blocked", text="", icon="LOCKED" if item.blocked else "UNLOCKED", emboss=False)
 
-            if context.scene.BIMLayerProperties.active_layer_id == item.ifc_definition_id:
+            if data.active_layer_id == item.ifc_definition_id:
                 op = row.operator("bim.select_layer_products", text="", icon="RESTRICT_SELECT_OFF")
                 op.layer = item.ifc_definition_id
                 row.operator("bim.edit_presentation_layer", text="", icon="CHECKMARK")
                 row.operator("bim.disable_editing_layer", text="", icon="CANCEL")
-            elif context.scene.BIMLayerProperties.active_layer_id:
+            elif data.active_layer_id:
                 op = row.operator("bim.select_layer_products", text="", icon="RESTRICT_SELECT_OFF")
                 op.layer = item.ifc_definition_id
                 row.operator("bim.remove_presentation_layer", text="", icon="X").layer = item.ifc_definition_id
diff --git a/src/bonsai/bonsai/tool/blender.py b/src/bonsai/bonsai/tool/blender.py
index 7ad78d2339..c02a9ce1d8 100644
--- a/src/bonsai/bonsai/tool/blender.py
+++ b/src/bonsai/bonsai/tool/blender.py
@@ -50,6 +50,7 @@ if TYPE_CHECKING:
     from bonsai.bim.prop import BIMProperties, BIMObjectProperties
     from bonsai.bim.module.attribute.prop import BIMAttributeProperties
     from bonsai.bim.module.csv.prop import CsvProperties
+    from bonsai.bim.module.constraint.prop import BIMConstraintProperties, BIMObjectConstraintProperties
     from bonsai.bim.module.diff.prop import DiffProperties
 
     T = TypeVar("T")
@@ -1644,13 +1645,24 @@ class Blender(bonsai.core.tool.Blender):
         dct = {cls.bl_idname: cls.ifc_element_type for cls in (BimTool.__subclasses__())}
         return types.MappingProxyType(dct)
 
+    @classmethod
+    def get_object_constraint_props(cls, obj: bpy.types.Object) -> BIMObjectConstraintProperties:
+        return obj.BIMObjectConstraintProperties
+
+    @classmethod
+    def get_constraint_props(cls) -> BIMConstraintProperties:
+        assert (scene := bpy.context.scene)
+        return scene.BIMConstraintProperties
+
     @classmethod
     def get_csv_props(cls) -> CsvProperties:
-        return bpy.context.scene.CsvProperties
+        assert (scene := bpy.context.scene)
+        return scene.CsvProperties
 
     @classmethod
     def get_diff_props(cls) -> DiffProperties:
-        return bpy.context.scene.DiffProperties
+        assert (scene := bpy.context.scene)
+        return scene.DiffProperties
 
     @classmethod
     def get_bim_props(cls, scene: Optional[bpy.types.Scene] = None) -> BIMProperties:
diff --git a/src/bonsai/bonsai/tool/loader.py b/src/bonsai/bonsai/tool/loader.py
index 6f58bbc665..05dbe0b594 100644
--- a/src/bonsai/bonsai/tool/loader.py
+++ b/src/bonsai/bonsai/tool/loader.py
@@ -101,7 +101,7 @@ class Loader(bonsai.core.tool.Loader):
         shape: Union[ifcopenshell.geom.ShapeElementType, ifcopenshell.geom.ShapeType],
         mesh: tool.Geometry.TYPES_WITH_MESH_PROPERTIES,
     ) -> None:
-        geometry = shape.geometry if hasattr(shape, "geometry") else shape
+        geometry = shape.geometry if isinstance(shape, ifcopenshell.geom.ShapeElementType) else shape
         tool.Geometry.get_mesh_props(mesh).ifc_definition_id = int(geometry.id.split("-")[0])
 
     @classmethod
diff --git a/src/bonsai/bonsai/tool/sequence.py b/src/bonsai/bonsai/tool/sequence.py
index f89afe3fec..eb8dd03277 100644
--- a/src/bonsai/bonsai/tool/sequence.py
+++ b/src/bonsai/bonsai/tool/sequence.py
@@ -39,6 +39,7 @@ from dateutil import parser
 from datetime import datetime
 from datetime import time as datetime_time
 from typing import Optional, Any, Union, Literal, TYPE_CHECKING, Iterable
+from mathutils import Color
 
 if TYPE_CHECKING:
     import bonsai.bim.prop
@@ -1449,7 +1450,7 @@ class Sequence(bonsai.core.tool.Sequence):
         obj.keyframe_insert(data_path="color", frame=product_frame["COMPLETED"])
 
     @classmethod
-    def animate_operation(cls, obj, start_frame, product_frame, color):
+    def animate_operation(cls, obj: bpy.types.Object, start_frame: int, product_frame, color: Color) -> None:
         if cls.earliest_frame is None or product_frame["STARTED"] < cls.earliest_frame:
             obj.color = (1.0, 1.0, 1.0, 1)
             obj.keyframe_insert(data_path="color", frame=start_frame)
diff --git a/src/ifcopenshell-python/ifcopenshell/__init__.py b/src/ifcopenshell-python/ifcopenshell/__init__.py
index 0942269ceb..97083d0938 100644
--- a/src/ifcopenshell-python/ifcopenshell/__init__.py
+++ b/src/ifcopenshell-python/ifcopenshell/__init__.py
@@ -260,7 +260,7 @@ def schema_by_name(
     return ifcopenshell_wrapper.schema_by_name(schema)
 
 
-def guess_format(path: Path) -> Union[str, None]:
+def guess_format(path: Path) -> Literal[".ifc", ".ifcZIP", ".ifcXML", ".ifcJSON", ".ifcSQLite", None]:
     """Guesses the IFC format using file extension
 
     IFCs may be serialised as different formats. The most common is a ``.ifc``
@@ -273,8 +273,6 @@ def guess_format(path: Path) -> Union[str, None]:
 
     Users generally won't call this function. The :func:`open` function uses
     this internally to guess the file format.
-
-    :return: Either .ifc, .ifcZIP, .ifcXML, .ifcJSON, .ifcSQLite, or None.
     """
     suffix = path.suffix.lower()
     if suffix == ".ifc":
diff --git a/src/ifcopenshell-python/ifcopenshell/ifcopenshell_wrapper.pyi b/src/ifcopenshell-python/ifcopenshell/ifcopenshell_wrapper.pyi
index 9f8db92bc6..5e631804ae 100644
--- a/src/ifcopenshell-python/ifcopenshell/ifcopenshell_wrapper.pyi
+++ b/src/ifcopenshell-python/ifcopenshell/ifcopenshell_wrapper.pyi
@@ -127,7 +127,7 @@ class BRep(Representation):
 class BRepElement(Element):
     def calculate_projected_surface_area(self, along_x, along_y, along_z): ...
     @property
-    def geometry(self): ...
+    def geometry(self) -> BRep: ...
     def geometry_pointer(self): ...
     @property
     def surface_area(self): ...
@@ -361,7 +361,7 @@ class Serialization(Representation):
 
 class SerializedElement(Element):
     @property
-    def geometry(self): ...
+    def geometry(self) -> Serialization: ...
 
 class SerializerSettings:
     def get_(self, name): ...
@@ -744,7 +744,7 @@ class ellipse(curve):
     def matrix(self): ...
 
 class entity(declaration):
-    def all_attributes(self): ...
+    def all_attributes(self) -> tuple[attribute, ...]: ...
     def all_inverse_attributes(self): ...
     def argument_types(self): ...
     def as_entity(self): ...
@@ -1127,10 +1127,10 @@ class revolve(sweep):
 class schema_definition:
     def declaration_by_name(self, *args: str) -> declaration: ...
     def declarations(self) -> tuple[declaration, ...]: ...
-    def entities(self): ...
+    def entities(self) -> tuple[entity, ...]: ...
     def enumeration_types(self): ...
     def instantiate(self, decl, data): ...
-    def name(self): ...
+    def name(self) -> str: ...
     def select_types(self): ...
     def type_declarations(self): ...
 
@@ -1446,7 +1446,7 @@ def polygons_to_svg(*args): ...
 def read(data): ...
 def register_schema(arg1): ...
 def schema_by_name(arg1: str) -> schema_definition: ...
-def schema_names(): ...
+def schema_names() -> tuple[str, ...]: ...
 def serialise(schema_name, shape_str, advanced): ...
 def set_feature(x, v): ...
 def set_log_format_json(): ...
@@ -1455,6 +1455,6 @@ def svg_to_line_segments(data, class_name): ...
 def svg_to_polygons(data, class_name): ...
 def taxonomy_item_repr(i): ...
 def tesselate(schema_name, shape_str, d): ...
-def turn_off_detailed_logging(): ...
-def turn_on_detailed_logging(): ...
-def version(): ...
+def turn_off_detailed_logging() -> None: ...
+def turn_on_detailed_logging() -> None: ...
+def version() -> str: ...
diff --git a/src/ifcopenshell-python/ifcopenshell/sql.py b/src/ifcopenshell-python/ifcopenshell/sql.py
index a77b5a85af..fc7f7f8fa9 100644
--- a/src/ifcopenshell-python/ifcopenshell/sql.py
+++ b/src/ifcopenshell-python/ifcopenshell/sql.py
@@ -96,9 +96,9 @@ class sqlite(file):
         self.preprocess_schema()
 
     def preprocess_schema(self) -> None:
-        self.ifc_class_subtypes = {}
+        self.ifc_class_subtypes: dict[str, Any] = {}
         self.ifc_class_attributes: dict[str, dict[str, ifcopenshell_wrapper.attribute]] = {}
-        self.ifc_class_inverse_attributes = {}
+        self.ifc_class_inverse_attributes: dict[str, Any] = {}
         self.ifc_class_references = {}
         self.ifc_class_inverses = {}
 
diff --git a/src/ifcopenshell-python/ifcopenshell/util/constraint.py b/src/ifcopenshell-python/ifcopenshell/util/constraint.py
index f4e18d61b3..2c370aa997 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/constraint.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/constraint.py
@@ -27,9 +27,7 @@ def get_constraints(product: ifcopenshell.entity_instance) -> list[ifcopenshell.
     Retrieves the constraints assigned to the `product`.
 
     :param product: The IFC element.
-    :type product: ifcopenshell.entity_instance
     :return: List of assigned constraints.
-    :rtype: list[ifcopenshell.entity_instance]
     """
     constraints = []
     for rel in product.HasAssociations or []:
@@ -43,9 +41,7 @@ def get_constrained_elements(constraint: ifcopenshell.entity_instance) -> set[if
     Retrieves the elements constrained by a `constraint`.
 
     :param product: The IFC element.
-    :type product: ifcopenshell.entity_instance
     :return: Set of elements constrained by a `constrant`.
-    :rtype: set[ifcopenshell.entity_instance]
     """
     elements = set()
     for rel in constraint.file.get_inverse(constraint):
@@ -59,9 +55,7 @@ def get_metrics(constraint: ifcopenshell.entity_instance) -> list[ifcopenshell.e
     Retrieves the list of nested constraints for a IfcObjective `constraint`.
 
     :param product: IfcObjective constraint.
-    :type product: ifcopenshell.entity_instance
     :return: List of nested constraints.
-    :rtype: list[ifcopenshell.entity_instance]
     """
 
     metrics = []