bim.add_transition

Added simple operator to add transition between two mep segments (now only rectangular collinear segments are supported). It also reuses the transition type that was previously used to connect segments of the same type. Demonstration - https://imgur.com/a/c1AOxj1
2026-08-10 17:58:20 +00:00 · 2023-08-04 14:46:48 +05:00
parent 4dc55e844c
commit 2c1c13f27e
5 changed files with 471 additions and 59 deletions
@@ -19,7 +19,7 @@
 import collections
 import ifcopenshell
 import ifcopenshell.api
-from math import cos, sin, pi
+from math import cos, sin, pi, tan, radians
 from mathutils import Vector, Matrix
 from itertools import chain

@@ -539,7 +539,7 @@ class ShapeBuilder:
                "Ref: https://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcPositiveLengthMeasure.htm#8.11.2.71.3-Formal-representation"
            )

-        if profile_or_curve.is_a() not in ("IfcArbitraryClosedProfileDef", "IfcArbitraryProfileDefWithVoids"):
+        if not profile_or_curve.is_a("IfcProfileDef"):
            profile_or_curve = self.profile(profile_or_curve)

        if position_y_axis:
@@ -579,6 +579,8 @@ class ShapeBuilder:
                representation_type = "AdvancedSweptSolid"
            elif "IfcExtrudedAreaSolid" in item_types:
                representation_type = "SweptSolid"
+            elif items[0].is_a("IfcTessellatedItem"):
+                representation_type = "Tessellation"
            elif items[0].is_a("IfcCurve") and items[0].Dim == 3:
                representation_type = "Curve3D"
            else:
@@ -746,8 +748,10 @@ class ShapeBuilder:

            ifc_curve = self.file.createIfcIndexedPolyCurve(Points=ifc_points, Segments=ifc_segments)
        return (points, segments, ifc_curve)
-    
-    def create_z_profile_lips_curve(self, FirstFlangeWidth, SecondFlangeWidth, Depth, Girth, WallThickness, FilletRadius):
+
+    def create_z_profile_lips_curve(
+        self, FirstFlangeWidth, SecondFlangeWidth, Depth, Girth, WallThickness, FilletRadius
+    ):
        x1 = FirstFlangeWidth
        x2 = SecondFlangeWidth
        y = Depth / 2
@@ -770,20 +774,21 @@ class ShapeBuilder:
            (-x1+t, -y+t),
            (-t/2,  -y+t)
        )
-        # fmt: on

        # option for no additional thickness in outer radius:
        # points, segments, ifc_curve = create_curve_from_coords(
        #   coords, fillets = (0, 1, 4, 5, 6, 7, 10, 11), fillet_radius=r, closed=True, ifc_file=ifc_file
        # )

-        points, segments, ifc_curve = self.get_simple_2dcurve_data(coords, 
+        points, segments, ifc_curve = self.get_simple_2dcurve_data(
+            coords, 
            fillets =     (0,   1,   4, 5, 6,   7,   10, 11), 
            fillet_radius=(r+t, r+t, r, r, r+t, r+t, r, r), 
            closed=True, create_ifc_curve=True)
+        # fmt: on

        return ifc_curve
-    
+
    def create_transition_arc_ifc(self, width, height, create_ifc_curve=False):
        # create an arc in the rectangle with specified width and height
        # if it's not possible to make a complete arc
@@ -814,4 +819,114 @@ class ShapeBuilder:
        points, segments, transition_arc = self.get_simple_2dcurve_data(
            curve_coords, fillets, fillet_radius, closed=False, create_ifc_curve=create_ifc_curve
        )
-        return points, segments, transition_arc
+        return points, segments, transition_arc
+
+    def polygonal_face_set(self, points, faces):
+        """
+        > `points` - list of points
+
+        > `faces` - list of faces consisted of point indices (points indices starting from 0)
+
+        < IfcPolygonalFaceSet
+        """
+
+        ifc_points = self.file.createIfcCartesianPointList3D(points)
+        ifc_faces = []
+        for face in faces:
+            face = [i + 1 for i in face]
+            ifc_faces.append(self.file.createIfcIndexedPolygonalFace(face))
+
+        face_set = self.file.createIfcPolygonalFaceSet(Coordinates=ifc_points, Faces=ifc_faces)
+
+        return face_set
+
+    def mep_transition_shape(self, start_segment, end_segment, start_length, end_length, angle=30.0):
+        """
+        returns tuple of Model/Body/MODEL_VIEW IfcRepresentation and transition shape data
+        """
+        # good default values from angle = 30/60 deg
+        # 30 degree angle will result in 75 degrees on the transition (= 90 - α/2) - https://i.imgur.com/tcoYDWu.png
+
+        # TODO: get rid of reliance on profiles
+        def get_profile(element):
+            material = ifcopenshell.util.element.get_material(element, should_skip_usage=True)
+            if material and material.is_a("IfcMaterialProfileSet") and len(material.MaterialProfiles) == 1:
+                return material.MaterialProfiles[0].Profile
+
+        start_profile = get_profile(start_segment)
+        end_profile = get_profile(end_segment)
+
+        # TODO: support more profiles
+        if not start_profile.is_a("IfcRectangleProfileDef") or not end_profile.is_a("IfcRectangleProfileDef"):
+            # Non rectangular profiles are not yet supported
+            return None, None
+
+        start_half_dim = V(start_profile.XDim / 2, start_profile.YDim / 2, start_length)
+        end_half_dim = V(end_profile.XDim / 2, end_profile.YDim / 2, end_length)
+
+        transition_items = []
+        end_extrusion_offset = V(0, 0, start_length)
+
+        def get_transition_legth(start_half_dim, end_half_dim, angle):
+            diff = start_half_dim.xy - end_half_dim.xy
+            diff = Vector([abs(i) for i in diff])
+            c = diff.x * tan(radians(90 - angle / 2))
+            a = diff.y
+            b = (c**2 - a**2) ** 0.5
+            return b
+
+        transition_length = get_transition_legth(start_half_dim, end_half_dim, angle)
+        faces = []
+        if transition_length != 0:
+            end_extrusion_offset.z += transition_length
+
+            faces += [(3, 4, 7, 0), (11, 8, 15, 12), (3, 11, 12, 4), (7, 15, 8, 0)]
+
+        # NOTE: clockwise order for correct face orientation
+        faces += [
+            # start extrusion
+            (0, 1, 2, 3),
+            (8, 11, 10, 9),
+            (0, 8, 9, 1),
+            (1, 9, 10, 2),
+            (2, 10, 11, 3),
+            # end extrusion
+            (4, 5, 6, 7),
+            (12, 15, 14, 13),
+            (4, 12, 13, 5),
+            (5, 13, 14, 6),
+            (6, 14, 15, 7),
+        ]
+        points = [
+            start_half_dim * V(-1, -1, 1),
+            start_half_dim * V(-1, -1, 0),
+            start_half_dim * V(1, -1, 0),
+            start_half_dim * V(1, -1, 1),
+            end_half_dim * V(1, -1, 0) + end_extrusion_offset,
+            end_half_dim * V(1, -1, 1) + end_extrusion_offset,
+            end_half_dim * V(-1, -1, 1) + end_extrusion_offset,
+            end_half_dim * V(-1, -1, 0) + end_extrusion_offset,
+            start_half_dim * V(-1, 1, 1),
+            start_half_dim * V(-1, 1, 0),
+            start_half_dim * V(1, 1, 0),
+            start_half_dim * V(1, 1, 1),
+            end_half_dim * V(1, 1, 0) + end_extrusion_offset,
+            end_half_dim * V(1, 1, 1) + end_extrusion_offset,
+            end_half_dim * V(-1, 1, 1) + end_extrusion_offset,
+            end_half_dim * V(-1, 1, 0) + end_extrusion_offset,
+        ]
+
+        face_set = self.polygonal_face_set(points, faces)
+        transition_items.append(face_set)
+
+        body = ifcopenshell.util.representation.get_context(self.file, "Model", "Body", "MODEL_VIEW")
+        representation = self.get_representation(body, transition_items, "Tesselation")
+        transition_data = {
+            "start_length": start_length,
+            "end_length": end_length,
+            "angle": angle,
+            "transition_length": transition_length,
+            "full_transition_length": start_length + transition_length + end_length,
+        }
+
+        return representation, transition_data