Adding Face radius and rotational_axis properties

src/build123d/topology/two_d.py

@@ -551,6 +551,22 @@ def length(self) -> None | float:
             result = face_vertices[-1].X - face_vertices[0].X
         return result
 
+    @property
+    def radius(self) -> None | float:
+        """Return the radius of a cylinder or sphere, otherwise None"""
+        if self.geom_type in [GeomType.CYLINDER, GeomType.SPHERE]:
+            return self.geom_adaptor().Radius()
+        else:
+            return None
+
+    @property
+    def rotational_axis(self) -> None | Axis:
+        """Get the rotational axis of a cylinder"""
+        if self.geom_type == GeomType.CYLINDER:
+            return Axis(self.geom_adaptor().Cylinder().Axis())
+        else:
+            return None
+
     @property
     def volume(self) -> float:
         """volume - the volume of this Face, which is always zero"""

tests/test_direct_api/test_face.py

@@ -41,7 +41,7 @@
 from build123d.geometry import Axis, Location, Plane, Pos, Vector
 from build123d.importers import import_stl
 from build123d.objects_curve import Line, Polyline, Spline, ThreePointArc
-from build123d.objects_part import Box, Cylinder
+from build123d.objects_part import Box, Cylinder, Sphere
 from build123d.objects_sketch import (
     Circle,
     Ellipse,
@@ -733,6 +733,25 @@ def test_axes_of_symmetry(self):
             make_face()
         self.assertEqual(len(skt.face().axes_of_symmetry), 0)
 
+    def test_radius_property(self):
+        c = Cylinder(1.5, 2).faces().filter_by(GeomType.CYLINDER)[0]
+        s = Sphere(3).faces().filter_by(GeomType.SPHERE)[0]
+        b = Box(1, 1, 1).faces()[0]
+        self.assertAlmostEqual(c.radius, 1.5, 5)
+        self.assertAlmostEqual(s.radius, 3, 5)
+        self.assertIsNone(b.radius)
+
+    def test_rotational_axis_property(self):
+        c = (
+            Cylinder(1.5, 2, rotation=(90, 0, 0))
+            .faces()
+            .filter_by(GeomType.CYLINDER)[0]
+        )
+        s = Sphere(3).faces().filter_by(GeomType.SPHERE)[0]
+        self.assertAlmostEqual(c.rotational_axis.direction, (0, -1, 0), 5)
+        self.assertAlmostEqual(c.rotational_axis.position, (0, 1, 0), 5)
+        self.assertIsNone(s.rotational_axis)
+
 
 class TestAxesOfSymmetrySplitNone(unittest.TestCase):
     def test_split_returns_none(self):