Add custom offset to slab IfcMaterialLayerSetUsage

src/bonsai/bonsai/bim/module/material/prop.py

@@ -208,6 +208,24 @@ class BIMObjectMaterialProperties(PropertyGroup):
     parameterized_profile_classes: EnumProperty(
         items=get_parameterized_profile_classes, name="Parameterized Profile Classes"
     )
+    use_custom_offset: BoolProperty(name="Use Custom Usage Settings")
+    custom_offset: FloatProperty(name="Use Custom Usage Settings", subtype="DISTANCE")
+    custom_slab_reference: EnumProperty(
+        items=[
+            ("TOP", "TOP", ""),
+            ("MIDDLE", "MIDDLE", ""),
+            ("BOTTOM", "BOTTOM", ""),
+        ],
+        name="Custom Offset Reference",
+    )
+    custom_wall_reference: EnumProperty(
+        items=[
+            ("EXTERIOR", "EXTERIOR", ""),
+            ("CENTER", "CENTER", ""),
+            ("INTERIOR", "INTERIOR", ""),
+        ],
+        name="Custom Offset Reference",
+    )
 
     if TYPE_CHECKING:
         material_type: str
@@ -221,3 +239,6 @@ class BIMObjectMaterialProperties(PropertyGroup):
         material_set_item_material: str
         profile_classes: str
         parameterized_profile_classes: str
+        use_custom_offset: bool
+        custom_offset: float
+        custom_offset_reference: str

src/bonsai/bonsai/bim/module/material/ui.py

@@ -231,6 +231,7 @@ class BIM_PT_object_material(Panel):
         bonsai.bim.helper.draw_attributes(self.props.material_set_attributes, self.layout)
         bonsai.bim.helper.draw_attributes(self.props.material_set_usage_attributes, self.layout)
 
+        self.custom_offset()
         if ObjectMaterialData.data["set_item_name"] == "profile" and not self.mprops.profiles:
             row = self.layout.row(align=True)
             row.label(text="No Profiles Available")
@@ -390,6 +391,20 @@ class BIM_PT_object_material(Panel):
                 else:
                     row.label(text="Exterior")
 
+    def custom_offset(self):
+        set_usage = ObjectMaterialData.data.get("set_usage", {})
+        layer_set_direction = set_usage.get("layer_set_direction")
+        if layer_set_direction:
+            box = self.layout.box()
+            row = box.row(align=True)
+            row.prop(self.props, "use_custom_offset", text="Use Custom Offset")
+            row = box.row(align=True)
+            if layer_set_direction == "AXIS2":
+                row.prop(self.props, "custom_wall_reference", text="Reference")
+            if layer_set_direction == "AXIS3":
+                row.prop(self.props, "custom_slab_reference", text="Reference")
+            row = box.row(align=True)
+            row.prop(self.props, "custom_offset", text="Custom Offset")
 
 class BIM_UL_materials(UIList):
     def draw_item(

src/bonsai/bonsai/bim/module/model/slab.py

@@ -292,6 +292,23 @@ class DumbSlabPlaner:
         if thickness == 0:
             return
 
+        layer_offset = layer_params["offset"]
+        self.props = tool.Material.get_object_material_props(obj)
+        if self.props.use_custom_offset:
+            custom_offset_reference = self.props.custom_offset_reference
+            custom_offset = self.props.custom_offset
+            direction_sense = layer_params["direction_sense"]
+            if (direction_sense == "POSITIVE" and custom_offset_reference == "TOP"):
+                layer_offset = custom_offset - thickness * self.unit_scale
+            if direction_sense == "POSITIVE" and custom_offset_reference == "MIDDLE":
+                layer_offset = custom_offset - (thickness / 2) * self.unit_scale
+            if (direction_sense == "POSITIVE" and custom_offset_reference == "BOTTOM") or (direction_sense == "NEGATIVE" and custom_offset_reference == "TOP"):
+                layer_offset = custom_offset
+            if direction_sense == "NEGATIVE" and custom_offset_reference == "MIDDLE":
+                layer_offset = custom_offset + (thickness / 2) * self.unit_scale
+            if (direction_sense == "NEGATIVE" and custom_offset_reference == "BOTTOM"):
+                layer_offset = custom_offset + thickness * self.unit_scale
+
         representation = ifcopenshell.util.representation.get_representation(element, "Model", "Body", "MODEL_VIEW")
         if representation:
             extrusion = tool.Model.get_extrusion(representation)
@@ -307,7 +324,7 @@ class DumbSlabPlaner:
                 direction_ratios = Vector(extrusion.ExtrudedDirection.DirectionRatios)
                 offset_direction = direction_ratios.copy()
                 perpendicular_depth = thickness * abs(1 / cos(existing_x_angle))
-                perpendicular_offset = layer_params["offset"] * abs(1 / cos(existing_x_angle)) / self.unit_scale
+                perpendicular_offset = layer_offset * abs(1 / cos(existing_x_angle)) / self.unit_scale
 
                 # Check angle and z direction to determine whether the extrusion direction is positive or negative
                 if (abs(existing_x_angle) < (pi / 2) and direction_ratios.z > 0) or (
@@ -336,6 +353,10 @@ class DumbSlabPlaner:
                     tool.Model.reset_extrusion_position(extrusion)
                 else:
                     position = offset_direction * perpendicular_offset
+                    material = ifcopenshell.util.element.get_material(element)
+                    if material:
+                        if material.is_a("IfcMaterialLayerSetUsage"):
+                            material.OffsetFromReferenceLine = position.z
                     if ifc_position:
                         ifc_position.Location.Coordinates = position
                     else: