diff --git a/src/bonsai/bonsai/bim/module/model/slab.py b/src/bonsai/bonsai/bim/module/model/slab.py
index 30512789eb..90fda177c9 100644
--- a/src/bonsai/bonsai/bim/module/model/slab.py
+++ b/src/bonsai/bonsai/bim/module/model/slab.py
@@ -84,7 +84,7 @@ class DumbSlabGenerator:
         polyline_data = bpy.context.scene.BIMPolylineProperties.insertion_polyline
         polyline_points = polyline_data[0].polyline_points if polyline_data else []
         self.location = Vector((polyline_points[0].x, polyline_points[0].y, self.container_obj.location.z))
-        self.polyline = [Vector((p.x, p.y, 0.0)) - self.location for p in polyline_points]
+        self.polyline = [tuple(Vector((p.x, p.y, 0.0)) - self.location) for p in polyline_points]
 
         if len(self.polyline) <= 2:
             return
diff --git a/src/ifcopenshell-python/ifcopenshell/api/geometry/add_slab_representation.py b/src/ifcopenshell-python/ifcopenshell/api/geometry/add_slab_representation.py
index c30375dd6a..90ebf0df1b 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/geometry/add_slab_representation.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/geometry/add_slab_representation.py
@@ -19,7 +19,6 @@
 import ifcopenshell.util.unit
 from ifcopenshell.util.data import Clipping
 from math import sin, cos
-from mathutils import Vector
 from typing import Any, Optional, Union
 
 
@@ -35,7 +34,7 @@ def add_slab_representation(
     # Planes are defined either by Clipping objects
     # or by dictionaries of arguments for `Clipping.parse`
     clippings: Optional[list[Union[Clipping, dict[str, Any]]]] = None,
-    polyline: Optional[list[Vector]] = None,
+    polyline: Optional[list[tuple]] = None,
 ) -> ifcopenshell.entity_instance:
     usecase = Usecase()
     usecase.file = file