diff --git a/src/blenderbim/blenderbim/bim/module/pset/operator.py b/src/blenderbim/blenderbim/bim/module/pset/operator.py
index 8896cd3f15..b3d55ba5e0 100644
--- a/src/blenderbim/blenderbim/bim/module/pset/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/pset/operator.py
@@ -27,10 +27,8 @@ import blenderbim.bim.helper
 import blenderbim.bim.handler
 import blenderbim.tool as tool
 import blenderbim.core.pset as core
-import blenderbim.core.qto as QtoCore
 import blenderbim.bim.module.pset.data
 from blenderbim.bim.ifc import IfcStore
-from blenderbim.bim.module.pset.qto_calculator import QtoCalculator
 
 
 class Operator:
diff --git a/src/blenderbim/blenderbim/bim/module/qto/__init__.py b/src/blenderbim/blenderbim/bim/module/qto/__init__.py
index 9924927fa0..dada98ae88 100644
--- a/src/blenderbim/blenderbim/bim/module/qto/__init__.py
+++ b/src/blenderbim/blenderbim/bim/module/qto/__init__.py
@@ -20,16 +20,17 @@ import bpy
 from . import ui, prop, operator
 
 classes = (
-    operator.AssignBaseQto,
     operator.CalculateCircleRadius,
     operator.CalculateEdgeLengths,
     operator.CalculateFaceAreas,
     operator.CalculateObjectVolumes,
-    operator.ExecuteQtoMethod,
+    operator.CalculateSingleQuantity,
     operator.PerformQuantityTakeOff,
-    operator.QuantifyObjects,
     prop.BIMQtoProperties,
-    ui.BIM_PT_qto_utilities,
+    ui.BIM_PT_qto,
+    ui.BIM_PT_qto_manual,
+    ui.BIM_PT_qto_simple,
+    ui.BIM_PT_qto_cost,
 )
 
 
diff --git a/src/blenderbim/blenderbim/bim/module/qto/calculator.py b/src/blenderbim/blenderbim/bim/module/qto/calculator.py
index 874bf37e72..bb9456cc50 100644
--- a/src/blenderbim/blenderbim/bim/module/qto/calculator.py
+++ b/src/blenderbim/blenderbim/bim/module/qto/calculator.py
@@ -38,17 +38,19 @@ VectorTuple = tuple[float, float, float]
 def get_units(o: bpy.types.Object, vg_index: int) -> int:
     return len([v for v in o.data.vertices if vg_index in [g.group for g in v.groups]])
 
-def get_linear_length(o: bpy.types.Object) -> float:
-    """_summary_: Returns the length of the longest edge of the object bounding box
 
-    :param blender-object o: Blender Object
-    :return float: Length
+def get_linear_length(o: bpy.types.Object) -> float:
+    """Returns the length of the longest edge of the object bounding box
+
+    :param o: Blender Object
+    :return: Length
     """
     x = (Vector(o.bound_box[4]) - Vector(o.bound_box[0])).length
     y = (Vector(o.bound_box[3]) - Vector(o.bound_box[0])).length
     z = (Vector(o.bound_box[1]) - Vector(o.bound_box[0])).length
     return max(x, y, z)
 
+
 def get_length(o: bpy.types.Object, vg_index: Optional[int] = None, main_axis: str = "x") -> float:
     if vg_index is None:
         x = (Vector(o.bound_box[4]) - Vector(o.bound_box[0])).length
@@ -74,22 +76,26 @@ def get_length(o: bpy.types.Object, vg_index: Optional[int] = None, main_axis: s
         length += get_edge_distance(o, e)
     return length
 
+
 def get_stair_length(obj: bpy.types.Object) -> float:
     length = get_length(obj)
     height = get_height(obj)
     stair_length = math.sqrt(pow(length, 2) + pow(height, 2))
     return stair_length
 
+
 def get_net_stair_area(obj: bpy.types.Object) -> float:
     OBB_obj = get_OBB_object(obj)
     OBB_net_footprint_area = get_net_footprint_area(OBB_obj)
     return OBB_net_footprint_area
 
+
 def get_gross_stair_area(obj: bpy.types.Object) -> float:
     OBB_obj = get_OBB_object(obj)
     OBB_gross_footprint_area = get_gross_footprint_area(OBB_obj)
     return OBB_gross_footprint_area
 
+
 def get_parametric_axis(obj: bpy.types.Object) -> Literal["AXIS2", "AXIS3", None]:
     relating_type = ifcopenshell.util.element.get_type(tool.Ifc.get_entity(obj))
     if relating_type:
@@ -105,6 +111,7 @@ def get_parametric_axis(obj: bpy.types.Object) -> Literal["AXIS2", "AXIS3", None
                 return None
     return None
 
+
 def get_covering_gross_area(obj: bpy.types.Object) -> float:
     parametrix_axis = get_parametric_axis(obj)
     if not parametrix_axis:
@@ -114,6 +121,7 @@ def get_covering_gross_area(obj: bpy.types.Object) -> float:
     elif parametrix_axis == "AXIS3":
         return get_gross_footprint_area(obj)
 
+
 def get_covering_net_area(obj: bpy.types.Object) -> float:
     parametrix_axis = get_parametric_axis(obj)
     if not parametrix_axis:
@@ -123,6 +131,7 @@ def get_covering_net_area(obj: bpy.types.Object) -> float:
     elif parametrix_axis == "AXIS3":
         return get_net_footprint_area(obj)
 
+
 def get_covering_width(obj: bpy.types.Object) -> float:
     parametrix_axis = get_parametric_axis(obj)
     if not parametrix_axis:
@@ -132,6 +141,7 @@ def get_covering_width(obj: bpy.types.Object) -> float:
     elif parametrix_axis == "AXIS3":
         return get_height(obj)
 
+
 def get_width(o: bpy.types.Object) -> float:
     """_summary_: Returns the width of the object bounding box
 
@@ -142,6 +152,7 @@ def get_width(o: bpy.types.Object) -> float:
     y = (Vector(o.bound_box[3]) - Vector(o.bound_box[0])).length
     return min(x, y)
 
+
 def get_height(o: bpy.types.Object) -> float:
     """_summary_: Returns the height of the object bounding box
 
@@ -150,38 +161,45 @@ def get_height(o: bpy.types.Object) -> float:
     """
     return (Vector(o.bound_box[1]) - Vector(o.bound_box[0])).length
 
+
 def get_opening_height(obj: bpy.types.Object) -> float:
     if is_opening_horizontal(obj):
         return get_width(obj)
     else:
         return get_height(obj)
 
+
 def get_opening_depth(obj: bpy.types.Object) -> float:
     if is_opening_horizontal(obj):
         return get_height(obj)
     else:
         return get_width(obj)
 
+
 def get_opening_mapping_area(obj: bpy.types.Object) -> float:
     if is_opening_horizontal(obj):
         return get_net_footprint_area(obj)
     else:
         return get_net_side_area(obj)
 
+
 def get_finish_ceiling_height(obj: bpy.types.Object) -> float:
     floor_height = get_finish_floor_height(obj)
     ceiling_height = get_ceiling_height(obj)
     finish_ceiling_height = ceiling_height - floor_height
     return finish_ceiling_height
 
+
 def get_max_global_z(obj: bpy.types.Object) -> float:
     z_values = [(obj.matrix_world @ Vector(co))[2] for co in obj.bound_box]
     return max(z_values)
 
+
 def get_min_global_z(obj: bpy.types.Object) -> float:
     z_values = [(obj.matrix_world @ Vector(co))[2] for co in obj.bound_box]
     return min(z_values)
 
+
 def get_finish_floor_height(obj: bpy.types.Object) -> float:
     space_min_z_value = get_min_global_z(obj)
 
@@ -200,6 +218,7 @@ def get_finish_floor_height(obj: bpy.types.Object) -> float:
 
     return flooring_max_z_value - space_min_z_value
 
+
 def get_ceiling_height(obj: bpy.types.Object) -> float:
     space_min_z_value = get_min_global_z(obj)
     space_max_z_value = get_max_global_z(obj)
@@ -219,6 +238,7 @@ def get_ceiling_height(obj: bpy.types.Object) -> float:
 
     return ceiling_min_z_value - space_min_z_value
 
+
 def get_net_perimeter(o: bpy.types.Object) -> float:
     parsed_edges = []
     shared_edges = []
@@ -234,6 +254,7 @@ def get_net_perimeter(o: bpy.types.Object) -> float:
         perimeter -= get_edge_key_distance(o, edge_key)
     return perimeter
 
+
 def get_gross_perimeter(o: bpy.types.Object) -> float:
     element = tool.Ifc.get_entity(o)
     mesh = get_gross_element_mesh(element)
@@ -242,14 +263,17 @@ def get_gross_perimeter(o: bpy.types.Object) -> float:
     delete_obj(gross_obj)
     return gross_perimeter
 
+
 def get_space_net_perimeter(obj: bpy.types.Object) -> float:
     pass
 
+
 def get_rectangular_perimeter(obj: bpy.types.Object) -> float:
     length = get_length(obj, main_axis="x")
     height = get_height(obj)
     return (length + height) * 2
 
+
 def get_lowest_polygons(o: bpy.types.Object) -> list[bpy.types.MeshPolygon]:
     lowest_polygons = []
     lowest_z = None
@@ -266,6 +290,7 @@ def get_lowest_polygons(o: bpy.types.Object) -> list[bpy.types.MeshPolygon]:
             lowest_z = z
     return lowest_polygons
 
+
 def get_highest_polygons(o: bpy.types.Object) -> list[bpy.types.MeshPolygon]:
     highest_polygons = []
     highest_z = None
@@ -282,12 +307,15 @@ def get_highest_polygons(o: bpy.types.Object) -> list[bpy.types.MeshPolygon]:
             highest_z = z
     return highest_polygons
 
+
 def get_edge_key_distance(obj: bpy.types.Object, edge_key: tuple[int, int]) -> float:
     return (obj.data.vertices[edge_key[1]].co - obj.data.vertices[edge_key[0]].co).length
 
+
 def get_edge_distance(obj: bpy.types.Object, edge: bpy.types.MeshEdge) -> float:
     return (obj.data.vertices[edge.vertices[1]].co - obj.data.vertices[edge.vertices[0]].co).length
 
+
 def get_net_floor_area(obj: bpy.types.Object) -> float:
     decompositions = get_obj_decompositions(obj)
     if not decompositions:
@@ -304,6 +332,7 @@ def get_net_floor_area(obj: bpy.types.Object) -> float:
 
     return total_net_floor_area
 
+
 def get_gross_ceiling_area(obj: bpy.types.Object) -> float:
     decompositions = get_obj_decompositions(obj)
     if not decompositions:
@@ -320,6 +349,7 @@ def get_gross_ceiling_area(obj: bpy.types.Object) -> float:
 
     return total_gross_ceiling_area
 
+
 def get_net_ceiling_area(obj: bpy.types.Object) -> float:
     decompositions = get_obj_decompositions(obj)
     if not decompositions:
@@ -340,6 +370,7 @@ def get_net_ceiling_area(obj: bpy.types.Object) -> float:
 
     return total_net_ceiling_area
 
+
 def get_space_net_volume(obj: bpy.types.Object) -> float:
     decompositions = get_obj_decompositions(obj)
     if not decompositions:
@@ -355,6 +386,7 @@ def get_space_net_volume(obj: bpy.types.Object) -> float:
 
     return total_space_net_volume
 
+
 def get_net_footprint_area(o: bpy.types.Object) -> float:
     """_summary_: Returns the area of the footprint of the object, excluding any holes
 
@@ -366,6 +398,7 @@ def get_net_footprint_area(o: bpy.types.Object) -> float:
         area += polygon.area
     return area
 
+
 def get_gross_footprint_area(o: bpy.types.Object) -> float:
     """_summary_: Returns the area of the footprint of the object, without related opening and excluding any holes
 
@@ -382,6 +415,7 @@ def get_gross_footprint_area(o: bpy.types.Object) -> float:
     delete_mesh(mesh)
     return gross_footprint_area
 
+
 def get_net_roofprint_area(o: bpy.types.Object) -> float:
     # Is roofprint the right word? Couldn't think of anything better - vulevukusej
     """_summary_: Returns the area of the net roofprint of the object, excluding any holes
@@ -394,6 +428,7 @@ def get_net_roofprint_area(o: bpy.types.Object) -> float:
         area += polygon.area
     return area
 
+
 def get_side_area(o: bpy.types.Object) -> float:
     # There are a few dumb options for this, but this seems the dumbest
     # until I get more practical experience on what works best.
@@ -402,6 +437,7 @@ def get_side_area(o: bpy.types.Object) -> float:
     z = (Vector(o.bound_box[1]) - Vector(o.bound_box[0])).length
     return max(x * z, y * z)
 
+
 def get_cross_section_area(obj: bpy.types.Object) -> float:
     representation = tool.Ifc.get().by_id(obj.data.BIMMeshProperties.ifc_definition_id)
     item = representation.Items[0]
@@ -418,6 +454,7 @@ def get_cross_section_area(obj: bpy.types.Object) -> float:
             return area
     # TODO handle other types of sections, and then fall back to mesh parsing
 
+
 def get_gross_surface_area(o: bpy.types.Object, vg_index: Optional[int] = None) -> float:
     if vg_index is None:
         if not has_openings(o):
@@ -436,21 +473,25 @@ def get_gross_surface_area(o: bpy.types.Object, vg_index: Optional[int] = None)
             area += polygon.area
     return area
 
+
 def get_net_surface_area(obj: bpy.types.Object) -> float:
     return get_mesh_area(obj.data)
 
+
 def get_mesh_area(mesh: bpy.types.Mesh) -> float:
     area = 0
     for polygon in mesh.polygons:
         area += polygon.area
     return area
 
+
 def is_polygon_in_vg(polygon: bpy.types.MeshPolygon, vertices_in_vg: list[bpy.types.MeshVertex]) -> bool:
     for v in polygon.vertices:
         if v not in vertices_in_vg:
             return False
     return True
 
+
 def get_net_volume(o: bpy.types.Object) -> float:
     o_mesh = bmesh.new()
     o_mesh.from_mesh(o.data)
@@ -458,6 +499,7 @@ def get_net_volume(o: bpy.types.Object) -> float:
     o_mesh.free()
     return volume
 
+
 def get_gross_volume(o: bpy.types.Object) -> float:
     if not has_openings(o):
         return get_net_volume(o)
@@ -473,17 +515,18 @@ def get_gross_volume(o: bpy.types.Object) -> float:
 
     return gross_volume
 
-def has_openings(
-    obj: bpy.types.Object
-) -> Union[ifcopenshell.entity_instance, list[ifcopenshell.entity_instance]]:
+
+def has_openings(obj: bpy.types.Object) -> Union[ifcopenshell.entity_instance, list[ifcopenshell.entity_instance]]:
     element = tool.Ifc.get_entity(obj)
     return element and getattr(element, "HasOpenings", [])
 
+
 def get_obj_decompositions(obj: bpy.types.Object) -> list[ifcopenshell.entity_instance]:
     element = tool.Ifc.get_entity(obj)
     decompositions = ifcopenshell.util.element.get_decomposition(element)
     return decompositions
 
+
 def get_gross_weight(obj: bpy.types.Object) -> Union[float, None]:
     obj_mass_density = get_obj_mass_density(obj)
     if not obj_mass_density:
@@ -492,6 +535,7 @@ def get_gross_weight(obj: bpy.types.Object) -> Union[float, None]:
     gross_weight = obj_mass_density * gross_volume
     return gross_weight
 
+
 def get_net_weight(obj: bpy.types.Object) -> Union[float, None]:
     obj_mass_density = get_obj_mass_density(obj)
     if not obj_mass_density:
@@ -500,6 +544,7 @@ def get_net_weight(obj: bpy.types.Object) -> Union[float, None]:
     net_weight = obj_mass_density * net_volume
     return net_weight
 
+
 def get_obj_mass_density(obj: bpy.types.Object) -> Union[float, None]:
     entity = tool.Ifc.get_entity(obj)
     material = ifcopenshell.util.element.get_material(entity)
@@ -546,6 +591,7 @@ def get_obj_mass_density(obj: bpy.types.Object) -> Union[float, None]:
         else:
             return
 
+
 def get_opening_type(opening: bpy.types.Object, obj: bpy.types.Object) -> Literal["OPENING", "RECESS"]:
     """_summary_: Returns the opening type - OPENING / RECESS
 
@@ -565,8 +611,8 @@ def get_opening_type(opening: bpy.types.Object, obj: bpy.types.Object) -> Litera
     # If an odd number of face-normal vectors intersect with the object, then the void is a recess, otherwise it's an opening
     return "OPENING" if ray_intersections % 2 == 0 else "RECESS"
 
+
 def get_opening_area(
-    
     obj: bpy.types.Object,
     angle_z1: int = 45,
     angle_z2: int = 135,
@@ -625,8 +671,8 @@ def get_opening_area(
 
     return total_opening_area
 
+
 def get_lateral_area(
-    
     obj: bpy.types.Object,
     subtract_openings: bool = True,
     exclude_end_areas: bool = False,
@@ -665,9 +711,7 @@ def get_lateral_area(
         top_axis = x_axis
 
     area = 0
-    total_opening_area = (
-        0 if subtract_openings else get_opening_area(obj, angle_z1=angle_z1, angle_z2=angle_z2)
-    )
+    total_opening_area = 0 if subtract_openings else get_opening_area(obj, angle_z1=angle_z1, angle_z2=angle_z2)
     polygons = obj.data.polygons
 
     for polygon in polygons:
@@ -685,6 +729,7 @@ def get_lateral_area(
         area += polygon.area
     return area + total_opening_area
 
+
 def get_gross_side_area(obj: bpy.types.Object) -> float:
     if not has_openings(obj):
         return get_net_side_area(obj)
@@ -693,14 +738,17 @@ def get_gross_side_area(obj: bpy.types.Object) -> float:
 
     return gross_side_area
 
+
 def get_net_side_area(obj: bpy.types.Object) -> float:
     net_side_area = get_lateral_area(obj, exclude_end_areas=True, main_axis="x") / 2
     return net_side_area
 
+
 def get_outer_surface_area(obj: bpy.types.Object) -> float:
     outer_surface_area = get_lateral_area(obj, exclude_end_areas=True, angle_z1=0, angle_z2=360)
     return outer_surface_area
 
+
 def get_end_area(obj: bpy.types.Object) -> float:
     element = tool.Ifc.get_entity(obj)
     gross_mesh = get_gross_element_mesh(element)
@@ -715,6 +763,7 @@ def get_end_area(obj: bpy.types.Object) -> float:
 
     return end_area
 
+
 def get_gross_top_area(obj: bpy.types.Object, angle: int = 45) -> float:
     """_summary_: Returns the gross top area of the object.
 
@@ -748,6 +797,7 @@ def get_gross_top_area(obj: bpy.types.Object, angle: int = 45) -> float:
             area += polygon.area
     return area + opening_area
 
+
 # curently net top area is larger then projected area, because its taking into account internal polygons, or window sills
 def get_net_top_area(obj: bpy.types.Object, angle: int = 45, ignore_internal: bool = True) -> float:
     """_summary_: Returns the net top area of the object.
@@ -775,6 +825,7 @@ def get_net_top_area(obj: bpy.types.Object, angle: int = 45, ignore_internal: bo
 
     return area
 
+
 def get_projected_area(obj, projection_axis: AxisType = "z", is_gross: bool = True) -> float:
     """_summary_: Returns the projected area of the object.
 
@@ -814,6 +865,7 @@ def get_projected_area(obj, projection_axis: AxisType = "z", is_gross: bool = Tr
         return projected_polygon.area + void_area
     return projected_polygon.area
 
+
 def get_OBB_object(obj: bpy.types.Object) -> bpy.types.Object:
     """_summary_: Returns the Oriented-Bounding-Box (OBB) of the object.
 
@@ -855,6 +907,7 @@ def get_OBB_object(obj: bpy.types.Object) -> bpy.types.Object:
 
     return new_OBB_object
 
+
 def get_AABB_object(obj: bpy.types.Object) -> bpy.types.Object:
     """_summary_: Returns the Axis-Aligned-Bounding-Box (AABB) of the object.
 
@@ -909,8 +962,8 @@ def get_AABB_object(obj: bpy.types.Object) -> bpy.types.Object:
 
     return new_AABB_object
 
+
 def get_bisected_obj(
-    
     obj: bpy.types.Object,
     plane_co_pos: VectorTuple,
     plane_no_pos: VectorTuple,
@@ -954,6 +1007,7 @@ def get_bisected_obj(
 
     return bis_obj
 
+
 def get_total_contact_area(obj: bpy.types.Object, class_filter: list[str] = ["IfcElement"]) -> float:
     """_summary_: Returns the total contact area of the object with other objects.
 
@@ -970,6 +1024,7 @@ def get_total_contact_area(obj: bpy.types.Object, class_filter: list[str] = ["If
 
     return total_contact_area
 
+
 def get_touching_objects(obj: bpy.types.Object, class_filter: list[str]) -> list[bpy.types.Object]:
     """_summary_: Returns a list of objects that are touching the object.
 
@@ -1019,6 +1074,7 @@ def get_touching_objects(obj: bpy.types.Object, class_filter: list[str]) -> list
 
     return touching_objects
 
+
 def get_contact_area(object1: bpy.types.Object, object2: bpy.types.Object) -> float:
     """_summary_: Returns the contact area between two objects.
 
@@ -1034,8 +1090,8 @@ def get_contact_area(object1: bpy.types.Object, object2: bpy.types.Object) -> fl
             total_area += get_intersection_between_polygons(object1, poly1, object2, poly2)
     return total_area
 
+
 def get_intersection_between_polygons(
-    
     object1: bpy.types.Object,
     poly1: bpy.types.MeshPolygon,
     object2: bpy.types.Object,
@@ -1083,9 +1139,8 @@ def get_intersection_between_polygons(
         # TopologicalError - Generated Geometry might be invalid
         return 0
 
-def create_shapely_polygon(
-    obj: bpy.types.Object, polygon: bpy.types.MeshPolygon, trans_matrix: Matrix
-) -> Polygon:
+
+def create_shapely_polygon(obj: bpy.types.Object, polygon: bpy.types.MeshPolygon, trans_matrix: Matrix) -> Polygon:
     """_summary_: Create a shapely polygon
 
     :param blender-object obj: Blender Object
@@ -1104,11 +1159,13 @@ def create_shapely_polygon(
         polygon_tuples.append((x, y))
     return Polygon(polygon_tuples)
 
+
 def get_gross_element_mesh(element: ifcopenshell.entity_instance) -> bpy.types.Mesh:
     settings = ifcopenshell.geom.settings()
     settings.set(settings.DISABLE_OPENING_SUBTRACTIONS, True)
     return create_mesh_from_shape(element, settings)
 
+
 def create_mesh_from_shape(
     element: ifcopenshell.entity_instance, settings: Optional[ifcopenshell.geom.settings] = None
 ) -> bpy.types.Mesh:
@@ -1138,11 +1195,13 @@ def create_mesh_from_shape(
     mesh.update()
     return mesh
 
+
 def get_bmesh_from_mesh(mesh: bpy.types.Mesh) -> bmesh.types.BMesh:
     bm = bmesh.new()
     bm.from_mesh(mesh)
     return bm
 
+
 def get_object_main_axis(o: bpy.types.Object) -> AxisType:
     """_summary_: Returns the main object axis. Useful for profile-defined objects.
 
@@ -1162,6 +1221,7 @@ def get_object_main_axis(o: bpy.types.Object) -> AxisType:
     else:
         return "x"
 
+
 def is_opening_horizontal(o: bpy.types.Object) -> bool:
     x = (Vector(o.bound_box[4]) - Vector(o.bound_box[0])).length
     y = (Vector(o.bound_box[3]) - Vector(o.bound_box[0])).length
@@ -1169,10 +1229,12 @@ def is_opening_horizontal(o: bpy.types.Object) -> bool:
 
     return z < x and z < y
 
+
 def delete_mesh(mesh: bpy.types.Mesh) -> None:
     mesh.user_clear()
     bpy.data.meshes.remove(mesh)
 
+
 def delete_obj(obj: bpy.types.Object) -> None:
     bpy.data.objects.remove(obj, do_unlink=True)
 
diff --git a/src/blenderbim/blenderbim/bim/module/qto/data.py b/src/blenderbim/blenderbim/bim/module/qto/data.py
index 7d5fcc6a66..1be10de8fd 100644
--- a/src/blenderbim/blenderbim/bim/module/qto/data.py
+++ b/src/blenderbim/blenderbim/bim/module/qto/data.py
@@ -19,9 +19,11 @@
 import bpy
 import blenderbim.tool as tool
 
+
 def refresh():
     QtoData.is_loaded = False
 
+
 class QtoData:
     data = {}
     is_loaded = False
@@ -29,9 +31,9 @@ class QtoData:
     @classmethod
     def load(cls):
         cls.data = {
-                "has_cost_item" : cls.has_cost_item(),
-                "relating_cost_items" : cls.relating_cost_items(),
-            }
+            "has_cost_item": cls.has_cost_item(),
+            "relating_cost_items": cls.relating_cost_items(),
+        }
 
         cls.is_loaded = True
 
@@ -53,23 +55,13 @@ class QtoData:
         for relating_cost_item in relating_cost_items:
             results.append(
                 {
-                    'cost_item_id' : relating_cost_item['cost_item_id'],
-                    'cost_item_name' : relating_cost_item['cost_item_name'],
-                    'quantity_id' : relating_cost_item['quantity_id'],
-                    'quantity_name' : relating_cost_item['quantity_name'],
-                    'quantity_value' : relating_cost_item['quantity_value'],
-                    'quantity_type' : relating_cost_item['quantity_type'],
+                    "cost_item_id": relating_cost_item["cost_item_id"],
+                    "cost_item_name": relating_cost_item["cost_item_name"],
+                    "quantity_id": relating_cost_item["quantity_id"],
+                    "quantity_name": relating_cost_item["quantity_name"],
+                    "quantity_value": relating_cost_item["quantity_value"],
+                    "quantity_type": relating_cost_item["quantity_type"],
                 }
             )
 
         return results
-
-
-
-
-
-
-
-
-
-
diff --git a/src/blenderbim/blenderbim/bim/module/qto/operator.py b/src/blenderbim/blenderbim/bim/module/qto/operator.py
index 7a12a45123..9be81dfafc 100644
--- a/src/blenderbim/blenderbim/bim/module/qto/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/qto/operator.py
@@ -23,7 +23,6 @@ import blenderbim.tool as tool
 import blenderbim.core.qto as core
 from blenderbim.bim.ifc import IfcStore
 from blenderbim.bim.module.qto import helper
-from blenderbim.bim.module.pset.qto_calculator import QtoCalculator
 
 
 class CalculateCircleRadius(bpy.types.Operator):
@@ -85,104 +84,37 @@ class CalculateObjectVolumes(bpy.types.Operator):
         return {"FINISHED"}
 
 
-class ExecuteQtoMethod(bpy.types.Operator):
-    bl_idname = "bim.execute_qto_method"
-    bl_label = "Execute Qto Method"
+class CalculateSingleQuantity(bpy.types.Operator, tool.Ifc.Operator):
+    bl_idname = "bim.calculate_single_quantity"
+    bl_label = "Calculate Single Quantity"
     bl_options = {"REGISTER", "UNDO"}
-
-    @classmethod
-    def poll(cls, context):
-        return context.selected_objects
-
-    def execute(self, context):
-        selected_mesh_objects = [o for o in context.selected_objects if o.type == "MESH"]
-        props = context.scene.BIMQtoProperties
-        result = 0
-        if props.qto_methods == "HEIGHT":
-            for obj in selected_mesh_objects:
-                result += helper.calculate_height(obj)
-        elif props.qto_methods == "VOLUME":
-            result = helper.calculate_volumes(selected_mesh_objects, context)
-        elif props.qto_methods == "FORMWORK":
-            result = helper.calculate_formwork_area(selected_mesh_objects, context)
-        elif props.qto_methods == "SIDE_FORMWORK":
-            result = helper.calculate_side_formwork_area(selected_mesh_objects, context)
-        elif props.qto_methods == "NetFootprintArea":
-            result = QtoCalculator().get_net_footprint_area(selected_mesh_objects[0])
-        elif props.qto_methods == "NetRoofprintArea":
-            result = QtoCalculator().get_net_roofprint_area(selected_mesh_objects[0])
-        elif props.qto_methods == "LateralArea":
-            result = QtoCalculator().get_lateral_area(selected_mesh_objects[0])
-        elif props.qto_methods == "TotalSurfaceArea":
-            result = QtoCalculator().get_total_surface_area(selected_mesh_objects[0])
-        elif props.qto_methods == "OpeningArea":
-            result = QtoCalculator().get_opening_area(selected_mesh_objects[0])
-        elif props.qto_methods == "GrossTopArea":
-            result = QtoCalculator().get_gross_top_area(selected_mesh_objects[0])
-        elif props.qto_methods == "NetTopArea":
-            result = QtoCalculator().get_net_top_area(selected_mesh_objects[0])
-        elif props.qto_methods == "ProjectedArea":
-            result = QtoCalculator().get_projected_area(selected_mesh_objects[0])
-        elif props.qto_methods == "TotalContactArea":
-            result = QtoCalculator().get_total_contact_area(selected_mesh_objects[0])
-        elif props.qto_methods == "ContactArea":
-            result = QtoCalculator().get_contact_area(selected_mesh_objects[0], selected_mesh_objects[1])
-        props.qto_result = str(round(result, 3))
-        return {"FINISHED"}
-
-
-class QuantifyObjects(bpy.types.Operator):
-    bl_idname = "bim.quantify_objects"
-    bl_label = "Quantify Objects"
-    bl_options = {"REGISTER", "UNDO"}
-
-    @classmethod
-    def poll(cls, context):
-        return IfcStore.get_file() and context.selected_objects
-
-    def execute(self, context):
-        return IfcStore.execute_ifc_operator(self, context)
-
-    def _execute(self, context):
-        props = context.scene.BIMQtoProperties
-        self.file = IfcStore.get_file()
-        for obj in (o for o in context.selected_objects if o.type == "MESH"):
-            if not obj.BIMObjectProperties.ifc_definition_id:
-                continue
-            result = 0
-            if props.qto_methods == "HEIGHT":
-                result = helper.calculate_height(obj)
-            elif props.qto_methods == "VOLUME":
-                result = helper.calculate_volumes([obj], context)
-            elif props.qto_methods == "FORMWORK":
-                result = helper.calculate_formwork_area([obj], context)
-            elif props.qto_methods == "SIDE_FORMWORK":
-                result = helper.calculate_side_formwork_area([obj], context)
-            if not result:
-                continue
-            result = round(result, 3)
-            qto = ifcopenshell.api.run(
-                "pset.add_qto",
-                self.file,
-                product=self.file.by_id(obj.BIMObjectProperties.ifc_definition_id),
-                name=props.qto_name,
-            )
-            ifcopenshell.api.run("pset.edit_qto", self.file, qto=qto, properties={props.prop_name: result})
-        return {"FINISHED"}
-
-
-class AssignBaseQto(bpy.types.Operator, tool.Ifc.Operator):
-    bl_idname = "bim.assign_objects_base_qto"
-    bl_label = "Assign IFC Object Quantity Set"
-    bl_options = {"REGISTER", "UNDO"}
-    bl_description = "Assign IFC quantity set to selected object"
+    bl_description = "Calculate a single quantity using a function on the selected objects"
 
     @classmethod
     def poll(cls, context):
         return tool.Ifc.get() and context.selected_objects
 
     def _execute(self, context):
-        core.assign_objects_base_qto(tool.Ifc, tool.Qto, selected_objects=context.selected_objects)
+        import ifc5d.qto
+
+        props = context.scene.BIMQtoProperties
+        elements = set()
+        for obj in context.selected_objects:
+            element = tool.Ifc.get_entity(obj)
+            if element:
+                elements.add(element)
+
+        rules = {
+            "calculators": {
+                props.calculator: {
+                    "IfcProduct": {props.qto_name: {props.prop_name: props.calculator_function}},
+                }
+            }
+        }
+
+        ifc_file = tool.Ifc.get()
+        results = ifc5d.qto.quantify(ifc_file, elements, rules)
+        ifc5d.qto.edit_qtos(ifc_file, results)
         return {"FINISHED"}
 
 
@@ -199,13 +131,14 @@ class PerformQuantityTakeOff(bpy.types.Operator, tool.Ifc.Operator):
     def _execute(self, context):
         import ifc5d.qto
 
+        props = context.scene.BIMQtoProperties
         elements = set()
         for obj in context.selected_objects:
             element = tool.Ifc.get_entity(obj)
             if element:
                 elements.add(element)
 
-        rules = ifc5d.qto.get_rules("IFC4QtoBaseQuantities")
+        rules = ifc5d.qto.rules[props.qto_rule]
 
         ifc_file = tool.Ifc.get()
         results = ifc5d.qto.quantify(ifc_file, elements, rules)
diff --git a/src/blenderbim/blenderbim/bim/module/qto/prop.py b/src/blenderbim/blenderbim/bim/module/qto/prop.py
index 8829c6178a..3cc1e9d446 100644
--- a/src/blenderbim/blenderbim/bim/module/qto/prop.py
+++ b/src/blenderbim/blenderbim/bim/module/qto/prop.py
@@ -17,6 +17,7 @@
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
 import bpy
+import ifc5d.qto
 from blenderbim.bim.prop import StrProperty, Attribute
 from bpy.types import PropertyGroup
 from bpy.props import (
@@ -31,34 +32,32 @@ from bpy.props import (
 )
 
 
+def get_qto_rule(self, context):
+    results = []
+    for rule_id, rule in ifc5d.qto.rules.items():
+        results.append((rule_id, rule["name"], rule["description"]))
+    return results
+
+
+def get_calculator(self, context):
+    results = []
+    for name, calculator in ifc5d.qto.calculators.items():
+        results.append((name, name, calculator.__doc__))
+    return results
+
+
+def get_calculator_function(self, context):
+    calculator = ifc5d.qto.calculators[self.calculator]
+    results = []
+    for function in calculator.get_functions():
+        results.append((function.id, function.name, function.description))
+    return results
+
+
 class BIMQtoProperties(PropertyGroup):
+    qto_rule: EnumProperty(items=get_qto_rule, name="Qto Rule")
+    calculator: EnumProperty(items=get_calculator, name="Calculator")
+    calculator_function: EnumProperty(items=get_calculator_function, name="Calculator Function")
     qto_result: StringProperty(default="", name="Qto Result")
-    qto_methods: EnumProperty(
-        items=[
-            ("HEIGHT", "Height", "Calculate the Z height of an object"),
-            ("VOLUME", "Volume", "Calculate the volume of an object"),
-            (
-                "FORMWORK",
-                "Formwork",
-                "Calculate the exposed formwork for all bottoms and sides (e.g. for beams and slabs) of one or more objects",
-            ),
-            (
-                "SIDE_FORMWORK",
-                "Side Formwork",
-                "Calculate the exposed formwork for all sides only (e.g. for columns) of one or more objects",
-            ),
-            ("NetFootprintArea", "Net footprint area", "Calculate the net footprint area"),
-            ("NetRoofprintArea", "Net roofprint area", "Calculate the net roofprint area"),
-            ("LateralArea", "Lateral area", "Calculate the lateral area"),
-            ("TotalSurfaceArea", "Total surface area", "Calculate the total surface area"),
-            ("OpeningArea", "Opening area", "Calculate the opening area"),
-            ("GrossTopArea", "Gross top area", "Calculate the gross top area"),
-            ("NetTopArea", "Net top area", "Calculate the net top area"),
-            ("ProjectedArea", "Projected area", "Calculate the projected area"),
-            ("TotalContactArea", "Total contact area", "Get the total contact area"),
-            ("ContactArea", "Contact area between two objects", "Get the contact area")
-        ],
-        name="Qto Methods",
-    )
-    qto_name: StringProperty(name="Qto Name")
-    prop_name: StringProperty(name="Prop Name")
+    qto_name: StringProperty(name="Qto Name", default="My_Qto")
+    prop_name: StringProperty(name="Prop Name", default="MyDimension")
diff --git a/src/blenderbim/blenderbim/bim/module/qto/ui.py b/src/blenderbim/blenderbim/bim/module/qto/ui.py
index c7a79d1522..c7f4863463 100644
--- a/src/blenderbim/blenderbim/bim/module/qto/ui.py
+++ b/src/blenderbim/blenderbim/bim/module/qto/ui.py
@@ -20,8 +20,8 @@ import bpy
 from blenderbim.bim.module.qto.data import QtoData
 
 
-class BIM_PT_qto_utilities(bpy.types.Panel):
-    bl_idname = "BIM_PT_qto_utilities"
+class BIM_PT_qto(bpy.types.Panel):
+    bl_idname = "BIM_PT_qto"
     bl_label = "Quantity Take-off"
     bl_options = {"DEFAULT_CLOSED"}
     bl_space_type = "PROPERTIES"
@@ -31,9 +31,56 @@ class BIM_PT_qto_utilities(bpy.types.Panel):
     bl_options = {"HIDE_HEADER"}
 
     def draw(self, context):
-        if not QtoData.is_loaded:
-            QtoData.load()
+        layout = self.layout
+        props = context.scene.BIMQtoProperties
 
+        row = layout.row()
+        if context.selected_objects:
+            row.label(text=f"Quantifying {len(context.selected_objects)} Selected Objects", icon="MOD_EDGESPLIT")
+        else:
+            row.label(text="Quantifying All Objects", icon="MOD_EDGESPLIT")
+        row = layout.row()
+        row.prop(props, "qto_rule", text="")
+        row = layout.row()
+        row.operator("bim.perform_quantity_take_off")
+
+
+class BIM_PT_qto_manual(bpy.types.Panel):
+    bl_idname = "BIM_PT_qto_manual"
+    bl_label = "Manual Quantification"
+    bl_options = {"DEFAULT_CLOSED"}
+    bl_space_type = "PROPERTIES"
+    bl_region_type = "WINDOW"
+    bl_context = "scene"
+    bl_parent_id = "BIM_PT_tab_qto"
+
+    def draw(self, context):
+        layout = self.layout
+        props = context.scene.BIMQtoProperties
+
+        row = layout.row()
+        row.prop(props, "calculator")
+        row = layout.row()
+        row.prop(props, "calculator_function", text="Function")
+
+        row = layout.row(align=True)
+        row.prop(props, "qto_name", text="")
+        row.prop(props, "prop_name", text="")
+
+        row = layout.row()
+        row.operator("bim.calculate_single_quantity")
+
+
+class BIM_PT_qto_simple(bpy.types.Panel):
+    bl_idname = "BIM_PT_qto_simple"
+    bl_label = "Simple Quantity Calculator"
+    bl_options = {"DEFAULT_CLOSED"}
+    bl_space_type = "PROPERTIES"
+    bl_region_type = "WINDOW"
+    bl_context = "scene"
+    bl_parent_id = "BIM_PT_tab_qto"
+
+    def draw(self, context):
         layout = self.layout
         props = context.scene.BIMQtoProperties
 
@@ -49,42 +96,44 @@ class BIM_PT_qto_utilities(bpy.types.Panel):
         row = layout.row(align=True)
         row.operator("bim.calculate_object_volumes")
 
-        row = layout.row(align=True)
-        row.prop(props, "qto_methods", text="")
-        row.operator("bim.execute_qto_method", icon="PROPERTIES", text="")
 
-        row = layout.row(align=True)
-        row.prop(props, "qto_name", text="")
-        row.prop(props, "prop_name", text="")
-        row.operator("bim.quantify_objects", icon="COPYDOWN", text="")
+class BIM_PT_qto_cost(bpy.types.Panel):
+    bl_idname = "BIM_PT_qto_cost"
+    bl_label = "Parametric Cost Relationships"
+    bl_options = {"DEFAULT_CLOSED"}
+    bl_space_type = "PROPERTIES"
+    bl_region_type = "WINDOW"
+    bl_context = "scene"
+    bl_parent_id = "BIM_PT_tab_qto"
 
-        row = layout.row(align=True)
-        row.operator("bim.assign_objects_base_qto")
+    def draw(self, context):
+        if not QtoData.is_loaded:
+            QtoData.load()
 
-        row = layout.row(align=True)
-        row.operator("bim.calculate_all_quantities", icon="MOD_EDGESPLIT")
+        if not context.selected_objects:
+            row = self.layout.row()
+            row.label(text="No Selected Object")
+            return
 
-        if context.selected_objects:
-            row = layout.row(align=True)
-            row.label(text=f"Relating Cost Item:")
-
-            if QtoData.data['has_cost_item']:
-                for relating_cost_item in QtoData.data['relating_cost_items']:
-                    row.label(text=f"\n")
-                    row = layout.row(align=True)
-                    row.label(text=f"Cost item name:")
-                    row.label(text=f"{relating_cost_item['cost_item_name']}")
-                    row = layout.row(align=True)
-                    row.label(text=f"Quantity name:")
-                    row.label(text=f"{relating_cost_item['quantity_name']}")
-                    row = layout.row(align=True)
-                    row.label(text=f"Quantity value:")
-                    row.label(text=f"{relating_cost_item['quantity_value']}")
-                    row = layout.row(align=True)
-                    row.label(text=f"Quantity type:")
-                    row.label(text=f"{relating_cost_item['quantity_type']}")
-                    row = layout.row(align=True)
-            else:
-                row = layout.row(align=True)
-                row.label(text = f"No cost item related")
+        if not QtoData.data["has_cost_item"]:
+            row = self.layout.row()
+            row.label(text="No Related Cost Item")
+            return
 
+        row = self.layout.row(align=True)
+        row.label(text="Relating Cost Item:")
+        for relating_cost_item in QtoData.data["relating_cost_items"]:
+            row.label(text="\n")
+            row = self.layout.row(align=True)
+            row.label(text="Cost item name:")
+            row.label(text=f"{relating_cost_item['cost_item_name']}")
+            row = self.layout.row(align=True)
+            row.label(text="Quantity name:")
+            row.label(text=f"{relating_cost_item['quantity_name']}")
+            row = self.layout.row(align=True)
+            row.label(text="Quantity value:")
+            row.label(text=f"{relating_cost_item['quantity_value']}")
+            row = self.layout.row(align=True)
+            row.label(text="Quantity type:")
+            row.label(text=f"{relating_cost_item['quantity_type']}")
+            row = self.layout.row(align=True)
diff --git a/src/blenderbim/blenderbim/core/qto.py b/src/blenderbim/blenderbim/core/qto.py
index a1495f3d68..1b31bd69ad 100644
--- a/src/blenderbim/blenderbim/core/qto.py
+++ b/src/blenderbim/blenderbim/core/qto.py
@@ -17,35 +17,14 @@
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
 from __future__ import annotations
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     import bpy
-    import ifcopenshell
     import blenderbim.tool as tool
-    from blenderbim.bim.module.pset.qto_calculator import QtoCalculator
 
 
 def calculate_circle_radius(qto: tool.Qto, obj: bpy.types.Object) -> float:
     result = qto.get_radius_of_selected_vertices(obj)
     qto.set_qto_result(result)
     return result
-
-
-def assign_objects_base_qto(ifc: tool.Ifc, qto: tool.Qto, selected_objects: list[bpy.types.Object]) -> None:
-    for obj in selected_objects:
-        assign_object_base_qto(ifc, qto, obj)
-
-
-def assign_object_base_qto(ifc: tool.Ifc, qto: tool.Qto, obj: bpy.types.Object) -> None:
-    product = ifc.get_entity(obj)
-    if not product:
-        return
-    base_quantity_name = qto.get_applicable_base_quantity_name(product)
-    if not base_quantity_name:
-        return
-    ifc.run(
-        "pset.add_qto",
-        product=product,
-        name=base_quantity_name,
-    )
diff --git a/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json b/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
index 3211ee6724..29b9045161 100644
--- a/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
+++ b/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
@@ -2,7 +2,7 @@
     "name": "IFC4 Base Quantities - IfcOpenShell",
     "description": "This ruleset quantifies every single possible standardised base quantity in IFC4 using only IfcOpenShell as a geometry processor.",
     "calculators": {
-        "IOSTriangulation": {
+        "IfcOpenShell": {
             "IfcActuator": {
                 "Qto_ActuatorBaseQuantities": {
                     "GrossWeight": null
diff --git a/src/ifc5d/ifc5d/qto.py b/src/ifc5d/ifc5d/qto.py
index 5957abbdc8..a4ddbd617e 100644
--- a/src/ifc5d/ifc5d/qto.py
+++ b/src/ifc5d/ifc5d/qto.py
@@ -23,16 +23,20 @@ import ifcopenshell.api
 import ifcopenshell.api.pset
 import ifcopenshell.util.selector
 import multiprocessing
-from typing import Optional
+from collections import namedtuple
+from typing import Iterable
 
 
-def get_rules(name: str):
-    cwd = os.path.dirname(os.path.realpath(__file__))
+Function = namedtuple("Function", ["id", "name", "description"])
+rules = {}
+
+cwd = os.path.dirname(os.path.realpath(__file__))
+for name in ("IFC4QtoBaseQuantities", "IFC4QtoBaseQuantitiesBlender"):
     with open(os.path.join(cwd, name + ".json"), "r") as f:
-        return json.load(f)
+        rules[name] = json.load(f)
 
 
-def quantify(ifc_file: ifcopenshell.file, elements: set[ifcopenshell.entity_instance], rules: dict):
+def quantify(ifc_file: ifcopenshell.file, elements: set[ifcopenshell.entity_instance], rules: dict) -> dict:
     results = {}
     for calculator, queries in rules["calculators"].items():
         calculator = calculators[calculator]
@@ -43,7 +47,7 @@ def quantify(ifc_file: ifcopenshell.file, elements: set[ifcopenshell.entity_inst
     return results
 
 
-def edit_qtos(ifc_file, results):
+def edit_qtos(ifc_file, results) -> None:
     for element, qtos in results.items():
         for name, quantities in qtos.items():
             qto = ifcopenshell.util.element.get_pset(element, name, should_inherit=False)
@@ -54,14 +58,17 @@ def edit_qtos(ifc_file, results):
             ifcopenshell.api.pset.edit_qto(ifc_file, qto=qto, properties=quantities)
 
 
-class IOSTriangulation:
+class IfcOpenShell:
+    """Calculates Model body context geometry using the default IfcOpenShell
+    iterator on triangulation elements."""
+
     @staticmethod
     def calculate(
         ifc_file: ifcopenshell.file,
         elements: set[ifcopenshell.entity_instance],
         qtos: dict,
         results: dict,
-    ):
+    ) -> None:
         import ifcopenshell
         import ifcopenshell.geom
         import ifcopenshell.util.shape
@@ -89,10 +96,10 @@ class IOSTriangulation:
         tasks = []
 
         if gross_qtos:
-            tasks.append((IOSTriangulation.create_iterator(ifc_file, gross_settings, elements), gross_qtos))
+            tasks.append((IfcOpenShell.create_iterator(ifc_file, gross_settings, list(elements)), gross_qtos))
 
         if net_qtos:
-            tasks.append((IOSTriangulation.create_iterator(ifc_file, net_settings, elements), net_qtos))
+            tasks.append((IfcOpenShell.create_iterator(ifc_file, net_settings, list(elements)), net_qtos))
 
         for iterator, qtos in tasks:
             if iterator.initialize():
@@ -108,13 +115,26 @@ class IOSTriangulation:
                         break
 
     @staticmethod
-    def create_iterator(ifc_file, settings, elements):
+    def create_iterator(
+        ifc_file: ifcopenshell.file, settings: ifcopenshell.geom.settings, elements: list[ifcopenshell.entity_instance]
+    ) -> ifcopenshell.geom.iterator:
         return ifcopenshell.geom.iterator(settings, ifc_file, multiprocessing.cpu_count(), include=elements)
 
+    @staticmethod
+    def get_functions() -> list[Function]:
+        return [
+            Function("get_volume", "Volume", "Calculates the volume of a manifold shape"),
+            Function("get_x", "X Length", "Calculates the length along the local X axis"),
+        ]
+
 
 class Blender:
+    """Calculates geometry based on currently loaded Blender objects."""
+
     @staticmethod
-    def calculate(ifc_file: ifcopenshell.file, elements: set[ifcopenshell.entity_instance], qtos: dict, results: dict):
+    def calculate(
+        ifc_file: ifcopenshell.file, elements: set[ifcopenshell.entity_instance], qtos: dict, results: dict
+    ) -> None:
         import blenderbim.tool as tool
         import blenderbim.bim.module.qto.calculator as calculator
 
@@ -132,5 +152,16 @@ class Blender:
                         formula_function = formula_functions[formula] = getattr(calculator, formula)
                     results[element][name][quantity] = formula_function(obj)
 
+    @staticmethod
+    def get_functions() -> list[Function]:
+        return [
+            Function(
+                "get_linear_length",
+                "Maximum Bounding Length",
+                "Calculates the length of the maximum local bounding box",
+            ),
+            Function("get_length", "Length", "Calculates the length assumed as the maximum of the local X or Y axis"),
+        ]
 
-calculators = {"Blender": Blender, "IOSTriangulation": IOSTriangulation}
+
+calculators = {"Blender": Blender, "IfcOpenShell": IfcOpenShell}