Ported PR #875 to refactored topology

src/build123d/topology/two_d.py

@@ -62,7 +62,7 @@
 from collections.abc import Iterable, Sequence
 
 import OCP.TopAbs as ta
-from OCP.BRep import BRep_Tool
+from OCP.BRep import BRep_Tool, BRep_Builder
 from OCP.BRepAdaptor import BRepAdaptor_Surface
 from OCP.BRepAlgo import BRepAlgo
 from OCP.BRepAlgoAPI import BRepAlgoAPI_Common
@@ -1453,10 +1453,13 @@ def __init__(
             obj = obj_list[0]
 
         if isinstance(obj, Face):
-            builder = BRepBuilderAPI_MakeShell(
-                BRepAdaptor_Surface(obj.wrapped).Surface().Surface()
-            )
-            obj = builder.Shape()
+            if obj.wrapped is None:
+                raise ValueError(f"Can't create a Shell from empty Face")
+            builder = BRep_Builder()
+            shell = TopoDS_Shell()
+            builder.MakeShell(shell)
+            builder.Add(shell, obj.wrapped)
+            obj = shell
         elif isinstance(obj, Iterable):
             obj = _sew_topods_faces([f.wrapped for f in obj])
 

tests/test_direct_api/test_shells.py

@@ -29,6 +29,7 @@
 import math
 import unittest
 
+from build123d.build_enums import GeomType
 from build123d.geometry import Plane, Rot, Vector
 from build123d.objects_curve import JernArc, Polyline, Spline
 from build123d.objects_sketch import Circle
@@ -42,6 +43,11 @@ def test_shell_init(self):
         box_shell = Shell(box_faces)
         self.assertTrue(box_shell.is_valid())
 
+    def test_shell_init_single_face(self):
+        face = Solid.make_cone(1, 0, 2).faces().filter_by(GeomType.CONE).first
+        shell = Shell(face)
+        self.assertTrue(shell.is_valid())
+
     def test_center(self):
         box_faces = Solid.make_box(1, 1, 1).faces()
         box_shell = Shell(box_faces)