See #1227. New connect wall API function since this can be done generically.

This will supersede the butt/mitre join functions we used to have.

src/ifcopenshell-python/ifcopenshell/api/geometry/__init__.py

@@ -43,6 +43,7 @@ from .add_window_representation import add_window_representation
 from .assign_representation import assign_representation
 from .connect_element import connect_element
 from .connect_path import connect_path
+from .connect_wall import connect_wall
 from .create_2pt_wall import create_2pt_wall
 from .disconnect_element import disconnect_element
 from .disconnect_path import disconnect_path
@@ -72,6 +73,7 @@ __all__ = [
     "assign_representation",
     "connect_element",
     "connect_path",
+    "connect_wall",
     "create_2pt_wall",
     "disconnect_element",
     "disconnect_path",

src/ifcopenshell-python/ifcopenshell/api/geometry/connect_wall.py

@@ -0,0 +1,63 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2025 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import numpy as np
+import ifcopenshell
+import ifcopenshell.api.owner
+import ifcopenshell.guid
+import ifcopenshell.util.element
+import ifcopenshell.util.placement
+import ifcopenshell.util.representation
+from typing import Optional
+
+
+def connect_wall(
+    file: ifcopenshell.file,
+    wall1: ifcopenshell.entity_instance,
+    wall2: ifcopenshell.entity_instance,
+    is_atpath: bool = False,
+) -> Optional[ifcopenshell.entity_instance]:
+    matrix1i = np.linalg.inv(ifcopenshell.util.placement.get_local_placement(wall1.ObjectPlacement))
+    matrix2 = ifcopenshell.util.placement.get_local_placement(wall2.ObjectPlacement)
+    axis1 = ifcopenshell.util.representation.get_reference_line(wall1)
+    axis2 = ifcopenshell.util.representation.get_reference_line(wall2)
+    axis2[0] = (matrix1i @ matrix2 @ np.concatenate((axis2[0], (0, 1))))[:2]
+    axis2[1] = (matrix1i @ matrix2 @ np.concatenate((axis2[1], (0, 1))))[:2]
+    midx = (axis1[0][0] + axis1[1][0]) / 2
+    starty = axis2[0][1]
+    endy = axis2[1][1]
+    y = axis1[0][1]
+
+    if (x := ifcopenshell.util.shape_builder.intersect_x_axis_2d(*axis2, y=y)) is None:
+        return
+
+    wall1_end = "ATEND" if x > midx else "ATSTART"
+    if is_atpath:
+        wall2_end = "ATPATH"
+    elif abs(y - starty) < abs(y - endy):
+        wall2_end = "ATSTART"
+    else:
+        wall2_end = "ATEND"
+
+    return ifcopenshell.api.geometry.connect_path(
+        file,
+        relating_element=wall1,
+        related_element=wall2,
+        relating_connection=wall1_end,
+        related_connection=wall2_end,
+    )

src/ifcopenshell-python/ifcopenshell/api/geometry/regenerate_wall_representation.py

@@ -93,7 +93,7 @@ class Regenerator:
         layers = self.get_layers(wall)
         if not layers:
             return
-        reference = self.get_reference_line(wall)
+        reference = ifcopenshell.util.representation.get_reference_line(wall, self.fallback_length)
         self.reference_p1, self.reference_p2 = reference
         self.wall_vectors = self.get_wall_vectors(wall)
         axes = self.get_axes(wall, reference, layers, self.wall_vectors["a"])
@@ -300,8 +300,8 @@ class Regenerator:
         print("joining", wall1, layers1, connection1)
         print("to", wall2, layers2, connection2)
 
-        reference1 = self.get_reference_line(wall1)
-        reference2 = self.get_reference_line(wall2)
+        reference1 = ifcopenshell.util.representation.get_reference_line(wall1, self.fallback_length)
+        reference2 = ifcopenshell.util.representation.get_reference_line(wall2, self.fallback_length)
         wall_vectors2 = self.get_wall_vectors(wall2)
         axes1 = self.get_axes(wall1, reference1, layers1, self.wall_vectors["a"])
         axes2 = self.get_axes(wall2, reference2, layers2, wall_vectors2["a"])
@@ -516,20 +516,6 @@ class Regenerator:
                 results.append(layer)
         return results
 
-    def get_reference_line(self, wall):
-        if axis := ifcopenshell.util.representation.get_representation(wall, "Plan", "Axis", "GRAPH_VIEW"):
-            for item in ifcopenshell.util.representation.resolve_representation(axis).Items:
-                if item.is_a("IfcPolyline"):
-                    points = item.Points
-                elif item.is_a("IfcIndexedPolyCurve"):
-                    points = item.Points.CoordList
-                else:
-                    continue
-                if points[0][0] < points[1][0]:  # An axis always goes in the +X direction
-                    return [np.array(points[0]), np.array(points[1])]
-                return [np.array(points[1]), np.array(points[0])]
-        return [np.array((0.0, 0.0)), np.array((self.fallback_length, 0.0))]
-
     def get_wall_vectors(self, wall):
         if body := ifcopenshell.util.representation.get_representation(wall, "Model", "Body", "MODEL_VIEW"):
             for item in ifcopenshell.util.representation.resolve_representation(body).Items:
@@ -572,7 +558,7 @@ class Regenerator:
         axes = [[p.copy() for p in reference]]
         # Apply usage to convert the Reference line into MlsBase
         sense_factor = 1
-        if (usage := ifcopenshell.util.element.get_material(wall)) and usage.is_a("IfcMaterialLayerSetUage"):
+        if (usage := ifcopenshell.util.element.get_material(wall)) and usage.is_a("IfcMaterialLayerSetUsage"):
             for point in axes[0]:
                 point[1] += usage.OffsetFromReferenceLine
             sense_factor = 1 if usage.DirectionSense == "POSITIVE" else -1

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

@@ -461,3 +461,22 @@ def get_material_style(
                     for style in item.Styles:
                         if style.is_a(ifc_class):
                             return style
+
+
+def get_reference_line(wall: ifcopenshell.entity_instance, fallback_length: float = 1.0):
+    """Fetch the reference axis that goes in the +X direction
+
+    :param wall: ifcopenshell.entity_instance
+    """
+    if axis := ifcopenshell.util.representation.get_representation(wall, "Plan", "Axis", "GRAPH_VIEW"):
+        for item in ifcopenshell.util.representation.resolve_representation(axis).Items:
+            if item.is_a("IfcPolyline"):
+                points = item.Points
+            elif item.is_a("IfcIndexedPolyCurve"):
+                points = item.Points.CoordList
+            else:
+                continue
+            if points[0][0] < points[1][0]:  # An axis always goes in the +X direction
+                return [np.array(points[0]), np.array(points[1])]
+            return [np.array(points[1]), np.array(points[0])]
+    return [np.array((0.0, 0.0)), np.array((fallback_length, 0.0))]