Fix #4052. Bug where invalid plane was generated due to missing X axis.

src/ifcopenshell-python/ifcopenshell/util/representation.py

@@ -19,6 +19,8 @@
 from __future__ import annotations
 import numpy as np
 import ifcopenshell
+import ifcopenshell.util.shape_builder
+from mathutils import Vector
 from typing import Any, Union
 from dataclasses import dataclass
 
@@ -131,15 +133,8 @@ class ClippingInfo:
     def apply(
         self, file: ifcopenshell.file, first_operand: ifcopenshell.entity_instance, unit_scale: float
     ) -> ifcopenshell.entity_instance:
-        # TODO: move to a separate method like `shape_builder.add_plane`
+        builder = ifcopenshell.util.shape_builder.ShapeBuilder(file)
-        def create_ifc_half_space_solid():
+        plane = builder.plane(location=Vector([i / unit_scale for i in self.location]), normal=Vector(self.normal))
-            location = file.createIfcCartesianPoint([i / unit_scale for i in self.location])
+        second_operand = file.createIfcHalfSpaceSolid(plane, False)
-            direction = file.createIfcDirection(self.normal)
-            axis_placement = file.createIfcAxis2Placement3D(location, direction, None)
-            plane = file.createIfcPlane(axis_placement)
-            halfspace_solid = file.createIfcHalfSpaceSolid(plane, False)
-            return halfspace_solid
-
-        second_operand = create_ifc_half_space_solid()
         first_operand = file.createIfcBooleanClippingResult("DIFFERENCE", first_operand, second_operand)
         return first_operand

src/ifcopenshell-python/ifcopenshell/util/shape_builder.py

@@ -171,6 +171,19 @@ class ShapeBuilder:
         #  self.file_file.createIfcAxis2Placement2D(tool.Ifc.get().createIfcCartesianPoint(center[0:2]))
         return ifc_curve
 
+    def plane(
+        self, location: Vector = Vector((0.0, 0.0, 0.0)).freeze(), normal: Vector = Vector((0.0, 0.0, 1.0)).freeze()
+    ):
+        location = self.file.createIfcCartesianPoint(location)
+        direction = self.file.createIfcDirection(normal)
+        if normal.to_tuple(2) == Vector((0.0, 0.0, 1.0)):
+            arbitrary_vector = Vector((0.0, 1.0, 0.0))
+        else:
+            arbitrary_vector = Vector((0.0, 0.0, 1.0))
+        x_axis = self.file.createIfcDirection(normal.cross(arbitrary_vector).normalized())
+        axis_placement = self.file.createIfcAxis2Placement3D(location, direction, x_axis)
+        return self.file.createIfcPlane(axis_placement)
+
     # TODO: explain points order for the curve_between_two_points
     # because the order is important and defines the center of the curve
     # currently it seems like the first point shifted by x-axis defines the center
@@ -846,9 +859,9 @@ class ShapeBuilder:
         # )
 
         points, segments, ifc_curve = self.get_simple_2dcurve_data(
-            coords, 
+            coords,
-            fillets =     (0,   1,   4, 5, 6,   7,   10, 11), 
+            fillets =     (0,   1,   4, 5, 6,   7,   10, 11),
-            fillet_radius=(r+t, r+t, r, r, r+t, r+t, r, r), 
+            fillet_radius=(r+t, r+t, r, r, r+t, r+t, r, r),
             closed=True, create_ifc_curve=True)
         # fmt: on