diff --git a/src/bonsai/test/bim/feature/type.feature b/src/bonsai/test/bim/feature/type.feature
index c32f7a8cfb..b85b9162c5 100644
--- a/src/bonsai/test/bim/feature/type.feature
+++ b/src/bonsai/test/bim/feature/type.feature
@@ -10,16 +10,6 @@ Scenario: Add type - adding via manual class assignment
     When I press "bim.assign_class"
     Then nothing happens
 
-Scenario: Add type - add from empty template
-    Given an empty IFC project
-    And I press "bim.launch_type_manager"
-    And I set "scene.BIMModelProperties.type_class" to "IfcWallType"
-    And I set "scene.BIMModelProperties.type_predefined_type" to "SOLIDWALL"
-    And I set "scene.BIMModelProperties.type_template" to "EMPTY"
-    When I press "bim.add_type"
-    Then the object "IfcWallType/TYPEX" is an "IfcWallType"
-    And the object "IfcWallType/TYPEX" has no data
-
 Scenario: Enable editing type
     Given an empty IFC project
     And I add a cube
@@ -73,7 +63,7 @@ Scenario: Assign type - assign to a type with representation maps
     And I press "bim.assign_type(relating_type={type}, related_object='IfcWall/Cube')"
     Then the object "IfcWall/Cube" has a "MappedRepresentation" representation of "Model/Body/MODEL_VIEW"
 
-Scenario: Assign type - assign to a type with a material layer set, which automatically recreates the shape
+Scenario: Assign type - assign to a type with a material layer set, which automatically recreates a mesh and resets dimensions
     Given an empty IFC project
     And I add a cube
     And the object "Cube" is selected
@@ -92,7 +82,28 @@ Scenario: Assign type - assign to a type with a material layer set, which automa
     And I press "bim.assign_type(relating_type={type}, related_object='IfcWall/Cube')"
     Then the object "IfcWall/Cube" has a "SweptSolid" representation of "Model/Body/MODEL_VIEW"
     And the object "IfcWall/Cube" has a "100" thick layered material containing the material "Default"
-    And the object "IfcWall/Cube" dimensions are "2,.1,3"
+    And the object "IfcWall/Cube" dimensions are "1,.1,1"
+
+Scenario: Assign type - assign to a type with a material layer set, which automatically recreates a solid (preserving parameters)
+    Given an empty IFC project
+    And I trigger "Add Element"
+    And I set the "Definition" property to "IfcElement"
+    And I set the "Class" property to "IfcWall"
+    And I set the "Representation" property to "Custom Extruded Solid"
+    And I click "OK"
+    And I add an empty
+    And the object "Empty" is selected
+    And I set "scene.BIMRootProperties.ifc_product" to "IfcElementType"
+    And I set "scene.BIMRootProperties.ifc_class" to "IfcWallType"
+    And I press "bim.assign_class"
+    And I press "bim.add_material()"
+    And I set "active_object.BIMObjectMaterialProperties.material_type" to "IfcMaterialLayerSet"
+    And I press "bim.assign_material"
+    When the variable "type" is "{ifc}.by_type('IfcWallType')[0].id()"
+    And I press "bim.assign_type(relating_type={type}, related_object='IfcWall/Unnamed')"
+    Then the object "IfcWall/Unnamed" has a "SweptSolid" representation of "Model/Body/MODEL_VIEW"
+    And the object "IfcWall/Unnamed" has a "100" thick layered material containing the material "Default"
+    And the object "IfcWall/Unnamed" dimensions are ".5,.1,.5"
 
 Scenario: Assign type - assign to a different type with a material layer set
     Given an empty IFC project
@@ -127,10 +138,10 @@ Scenario: Assign type - assign to a different type with a material layer set
     When I press "bim.assign_type(relating_type={type}, related_object='IfcWall/Cube')"
     Then the object "IfcWall/Cube" has a "SweptSolid" representation of "Model/Body/MODEL_VIEW"
     And the object "IfcWall/Cube" has a "100" thick layered material containing the material "Default"
-    And the object "IfcWall/Cube" dimensions are "2,.1,3"
+    And the object "IfcWall/Cube" dimensions are "1,.1,1"
     When I press "bim.assign_type(relating_type={type2}, related_object='IfcWall/Cube')"
     Then the object "IfcWall/Cube" has a "200" thick layered material containing the material "Default"
-    And the object "IfcWall/Cube" dimensions are "2,.2,3"
+    And the object "IfcWall/Cube" dimensions are "1,.2,1"
 
 Scenario: Assign type - assign to a type with a material profile set
     Given an empty IFC project
diff --git a/src/ifcopenshell-python/ifcopenshell/util/representation.py b/src/ifcopenshell-python/ifcopenshell/util/representation.py
index ca79c4ec88..94ec3f8579 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/representation.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/representation.py
@@ -490,11 +490,15 @@ def get_reference_line(wall: ifcopenshell.entity_instance, fallback_length: floa
                 return [np.array(points[0]), np.array(points[1])]
             return [np.array(points[1]), np.array(points[0])]
     elif extrusions := ifcopenshell.util.shape.get_base_extrusions(wall):
-        for item in extrusions:
-            if item.is_a("IfcPolyline"):
-                x = [p[0][0] for p in item.Points]
-            elif item.is_a("IfcIndexedPolyCurve"):
-                x = [p[0] for p in item.Points.CoordList]
+        for extrusion in extrusions:
+            profile = extrusion.SweptArea
+            curve = getattr(profile, "OuterCurve", None)
+            if not curve:
+                continue
+            elif curve.is_a("IfcPolyline"):
+                x = [p[0][0] for p in curve.Points]
+            elif curve.is_a("IfcIndexedPolyCurve"):
+                x = [p[0] for p in curve.Points.CoordList]
             else:
                 continue
             return [np.array((min(x), 0.0)), np.array((max(x), 0.0))]