Support material layer set usage negative direction sense for parametric walls

src/blenderbim/blenderbim/bim/module/model/data.py

@@ -188,14 +188,17 @@ class AuthoringData:
         if not ifc_class and ifc_classes:
             ifc_class = ifc_classes[0][0]
         if ifc_class:
-            elements = sorted(tool.Ifc.get().by_type(ifc_class), key=lambda s: s.Name)
+            elements = sorted(tool.Ifc.get().by_type(ifc_class), key=lambda s: s.Name or "Unnamed")
             results.extend(elements)
             return results
         return []
 
     @classmethod
     def relating_types(cls, ifc_class=None):
-        return [(str(e.id()), e.Name, e.Description or "") for e in cls.constr_class_entities(ifc_class=ifc_class)]
+        return [
+            (str(e.id()), e.Name or "Unnamed", e.Description or "")
+            for e in cls.constr_class_entities(ifc_class=ifc_class)
+        ]
 
     @classmethod
     def relating_types_browser(cls):
@@ -331,7 +334,7 @@ class ArrayData:
     @classmethod
     def load(cls):
         cls.is_loaded = True
-        cls.data = { "parameters": cls.parameters() }
+        cls.data = {"parameters": cls.parameters()}
 
     @classmethod
     def parameters(cls):

src/blenderbim/blenderbim/tool/model.py

@@ -92,14 +92,19 @@ class Model(blenderbim.core.tool.Model):
         unit_scale = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
         offset = 0.0
         thickness = 0.0
+        direction_sense = "POSITIVE"
         material = ifcopenshell.util.element.get_material(element)
         if material:
             if material.is_a("IfcMaterialLayerSetUsage"):
                 offset = material.OffsetFromReferenceLine * unit_scale
+                direction_sense = material.DirectionSense
                 material = material.ForLayerSet
             if material.is_a("IfcMaterialLayerSet"):
                 thickness = sum([l.LayerThickness for l in material.MaterialLayers]) * unit_scale
-        return {"thickness": thickness, "offset": offset}
+        if direction_sense == "NEGATIVE":
+            thickness *= -1
+            offset *= -1
+        return {"thickness": thickness, "offset": offset, "direction_sense": direction_sense}
 
     @classmethod
     def get_manual_booleans(cls, element):