bends - support for start and end segments

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

@@ -882,12 +882,6 @@ class MEPAddBend(bpy.types.Operator, tool.Ifc.Operator):
         ifc_file = tool.Ifc.get()
         si_conversion = ifcopenshell.util.unit.calculate_unit_scale(ifc_file)
 
-        self.start_length, self.end_length = 0, 0
-
-        if not (self.start_length == 0 and self.end_length == 0):
-            self.report({"ERROR"}, f"Only zero lengths are now supported.")
-            return {"CANCELLED"}
-
         if self.start_segment_id and self.end_segment_id:
             start_element = ifc_file.by_id(self.start_segment_id)
             end_element = ifc_file.by_id(self.end_segment_id)
@@ -971,7 +965,7 @@ class MEPAddBend(bpy.types.Operator, tool.Ifc.Operator):
             end_segment_data["end_point"]: end_segment_data["end_port"],
         }
 
-        get_z_basis = lambda o: o.matrix_world.col[2].normalized().to_3d()
+        get_z_basis = lambda o: tool.Cad.get_basis_vector(o, 2)
         segments_intersection_ws = tool.Cad.intersect_edges(
             (start_object.location, start_object.location + get_z_basis(start_object)),
             (end_object.location, end_object.location + get_z_basis(end_object)),
@@ -1058,8 +1052,8 @@ class MEPAddBend(bpy.types.Operator, tool.Ifc.Operator):
             current_start_offset = segments_intersection.length
             current_end_offset = (segments_intersection - profile_offset).length
 
-            start_extend = current_start_offset - required_offset
-            end_extend = current_end_offset - required_offset
+            start_extend = current_start_offset - (required_offset + self.start_length)
+            end_extend = current_end_offset - (required_offset + self.end_length)
 
             return start_extend, end_extend
 

src/blenderbim/blenderbim/tool/cad.py

@@ -526,3 +526,7 @@ class Cad:
         if cls.is_x(value, 0):
             return 0
         return 1 if value > 0 else -1
+
+    @classmethod
+    def get_basis_vector(cls, object, axis_i):
+        return object.matrix_world.col[axis_i].normalized().to_3d()

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

@@ -1356,10 +1356,26 @@ class ShapeBuilder:
         O[lateral_axis] = (radius + profile_dim[lateral_axis]) * lateral_sign
         theta = angle
 
+        def get_circle_point(angle, radius):
+            point = V(0, 0, 0)
+            angle -= pi / 2
+            # fmt: off
+            point.z             = z_sign       * cos(angle) * radius
+            point[lateral_axis] = lateral_sign * sin(angle) * radius
+            # fmt: on
+            return point
+
+        def get_circle_tangent(angle):
+            tangent = V(0, 0, 0)
+            tangent.z = cos(angle) * z_sign
+            tangent[lateral_axis] = sin(angle) * lateral_sign
+            return tangent
+
         def get_bend_representation_item():
             if is_circular_profile:
                 theta_segments = [0, theta / 2, theta]
             else:
+                # TODO: try to replace with curves instead of segments
                 # get as much segment_length segments as possible
                 segment_length = pi / 20
                 num_segments = ceil(theta / segment_length)
@@ -1371,32 +1387,27 @@ class ShapeBuilder:
             r = radius
             if is_circular_profile:
                 r += profile_dim[lateral_axis]
+            else:
+                outer_r = r + 2 * profile_dim[lateral_axis]
 
             for cur_theta in theta_segments:
-                cur_theta -= pi / 2
-                inner = V(0, 0, 0)
-                # fmt: off
-                inner.z             = z_sign       * cos(cur_theta) * r
-                inner[lateral_axis] = lateral_sign * sin(cur_theta) * r
-                inner_points.append(inner)
-
+                inner_points.append(get_circle_point(cur_theta, r))
                 if not is_circular_profile:
-                    outer = V(0, 0, 0)
-                    outer.z             = z_sign       * cos(cur_theta) * (r + 2 * profile_dim[lateral_axis])
-                    outer[lateral_axis] = lateral_sign * sin(cur_theta) * (r + 2 * profile_dim[lateral_axis])
-                    outer_points.append(outer)
-                # fmt: on
+                    outer_points.append(get_circle_point(cur_theta, outer_r))
 
             points = inner_points + outer_points[::-1]
             points = [p + O for p in points]
+            offset = V(0, 0, 0)
+            offset.z = z_sign * start_length
 
             if is_circular_profile:
-                bend_path = self.polyline(points, closed=False, arc_points=[1])
+                bend_path = self.polyline(points, closed=False, arc_points=[1], position_offset=offset)
                 bend = self.create_swept_disk_solid(bend_path, profile_dim[lateral_axis])
             else:
                 main_axes = lambda v: getattr(v, "xy"[lateral_axis] + "z")
-                offset = V(0, 0, 0)
+
                 offset[non_lateral_axis] = -profile_dim[non_lateral_axis]
+
                 extrusion_kwargs = self.extrude_kwargs("XY"[non_lateral_axis])
                 profile_curve = self.polyline([main_axes(p) for p in points], closed=True)
                 bend = self.extrude(
@@ -1405,6 +1416,28 @@ class ShapeBuilder:
             return bend
 
         rep_items.append(get_bend_representation_item())
+        if start_length:
+            rep_items.append(self.extrude(profile, start_length, extrusion_vector=V(0, 0, z_sign)))
+        if end_length:
+            end_position = O + get_circle_point(theta, radius + profile_dim[lateral_axis])
+            end_position.z += start_length * z_sign
+
+            # define extrusion space for the segment after the bend
+            z_axis = get_circle_tangent(theta)
+            extrude_kwargs = {
+                "position_z_axis": z_axis,
+                "extrusion_vector": Vector((0, 0, 1)),
+            }
+            # since we are sure that tangent involves only two axis
+            # it's safe to assume that non lateral axis is untouched
+            if lateral_axis == 0:
+                x_axis = z_axis.cross(Vector((0, 1, 0)))
+            else:
+                x_axis = Vector((1, 0, 0))
+            extrude_kwargs["position_x_axis"] = x_axis
+
+            rep_items.append(self.extrude(profile, end_length, end_position, **extrude_kwargs))
+
         body = ifcopenshell.util.representation.get_context(self.file, "Model", "Body", "MODEL_VIEW")
         rep = self.get_representation(body, rep_items)