API now supports adding representations using the Sverchok geometry structure

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

@@ -0,0 +1,84 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2022 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 ifcopenshell.util.unit
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {
+            "context": None,  # IfcGeometricRepresentationContext
+            # Vertices, edges, and faces are given in the form of: [item1, item2, item3, ...]
+            # ... where itemN = [(0., 0., 0.), (1., 1., 1.), (x, y, z), ...]
+            "vertices": None,  # A list of coordinates
+            # ... where itemN = [(0, 1), (1, 2), (v1, v2), ...]
+            "edges": None,  # A list of edges, represented by vertex index pairs
+            # ... where itemN = [(0, 1, 2), (5, 4, 2, 3), (v1, v2, v3, ... vN), ...]
+            "faces": None,  # A list of polygons, represented by vertex indices
+            "coordinate_offset": None,  # Optionally apply a vector offset to all coordinates
+            "unit_scale": None,  # A scale factor to apply for all vectors in case the unit is different
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        if self.settings["unit_scale"] is None:
+            self.settings["unit_scale"] = ifcopenshell.util.unit.calculate_unit_scale(self.file)
+        return self.create_mesh_representation()
+
+    def create_mesh_representation(self):
+        if self.file.schema == "IFC2X3":
+            return self.create_faceted_brep()
+        return self.create_polygonal_face_set()
+
+    def create_faceted_brep(self):
+        items = []
+        for i in range(0, len(self.settings["vertices"])):
+            vertices = [
+                self.file.createIfcCartesianPoint(self.convert_si_to_unit(v)) for v in self.settings["vertices"][i]
+            ]
+            faces = [
+                self.file.createIfcFace(
+                    [self.file.createIfcFaceOuterBound(self.file.createIfcPolyLoop([vertices[v] for v in f]), True)]
+                )
+                for f in self.settings["faces"][i]
+            ]
+            items.append(self.file.createIfcFacetedBrep(self.file.createIfcClosedShell(faces)))
+        return self.file.createIfcShapeRepresentation(
+            self.settings["context"], self.settings["context"].ContextIdentifier, "Brep", items
+        )
+
+    def create_polygonal_face_set(self):
+        items = []
+        for i in range(0, len(self.settings["vertices"])):
+            coordinates = self.file.createIfcCartesianPointList3D(
+                [self.convert_si_to_unit(v) for v in self.settings["vertices"][i]]
+            )
+            faces = [self.file.createIfcIndexedPolygonalFace([v + 1 for v in f]) for f in self.settings["faces"][i]]
+            items.append(self.file.createIfcPolygonalFaceSet(coordinates, None, faces))
+        return self.file.createIfcShapeRepresentation(
+            self.settings["context"], self.settings["context"].ContextIdentifier, "Tessellation", items
+        )
+
+    def convert_si_to_unit(self, co):
+        if isinstance(co, tuple):
+            return [self.convert_si_to_unit(o) for o in co]
+        if self.settings["coordinate_offset"]:
+            return (co / self.settings["unit_scale"]) + self.settings["coordinate_offset"]
+        return co / self.settings["unit_scale"]