Merge pull request #465 from voneiden/algebra-minus-dimensions

Support multidimensional minus in algebra mode

src/build123d/topology.py

@@ -1694,11 +1694,13 @@ class Shape(NodeMixin):
         """cut shape from self operator -"""
         others = other if isinstance(other, (list, tuple)) else [other]
 
-        if not all([type(other)._dim == type(self)._dim for other in others]):
-            raise ValueError(
-                f"Only shapes with the same dimension can be subtracted "
-                f"not {type(self).__name__} and {type(other).__name__}"
-            )
+        for _other in others:
+            if type(_other)._dim < type(self)._dim:
+                raise ValueError(
+                    f"Only shapes with equal or greater dimension can be subtracted: "
+                    f"not {type(self).__name__} ({type(self)._dim}D) and "
+                    f"{type(_other).__name__} ({type(_other)._dim}D)"
+                )
 
         new_shape = None
         if self.wrapped is None:

tests/test_algebra.py

@@ -602,6 +602,54 @@ class AlgebraTests(unittest.TestCase):
         with self.assertRaises(ValueError):
             r = b & Sketch()
 
+    def test_1d_2d_minus(self):
+        line = Line((0, 0), (1, 1))
+        rectangle = Rectangle(1, 1)
+        r = line - rectangle
+        vertices = r.vertices()
+        self.assertEquals(len(vertices), 2)
+        self.assertTupleAlmostEquals(vertices[0], (0.5, 0.5, 0.0), 6)
+        self.assertTupleAlmostEquals(vertices[1], (1.0, 1.0, 0.0), 6)
+
+    def test_1d_3d_minus(self):
+        line = Line((0, 0), (1, 1))
+        box = Box(1, 1, 1)
+        r = line - box
+        vertices = r.vertices()
+        self.assertEquals(len(vertices), 2)
+        self.assertTupleAlmostEquals(vertices[0], (0.5, 0.5, 0.0), 6)
+        self.assertTupleAlmostEquals(vertices[1], (1.0, 1.0, 0.0), 6)
+
+    def test_2d_3d_minus(self):
+        rectangle = Pos(0.5, 0, 0) * Rectangle(1, 1)
+        box = Box(1, 1, 1)
+        r = rectangle - box
+        vertices = r.vertices()
+        self.assertEquals(len(vertices), 4)
+        self.assertTupleAlmostEquals(vertices[0], (0.5, -0.5, 0.0), 6)
+        self.assertTupleAlmostEquals(vertices[1], (0.5, 0.5, 0.0), 6)
+        self.assertTupleAlmostEquals(vertices[2], (1.0, 0.5, 0.0), 6)
+        self.assertTupleAlmostEquals(vertices[3], (1.0, -0.5, 0.0), 6)
+        print(vertices)
+
+    def test_3d_2d_minus(self):
+        box = Box(1, 1, 1)
+        rectangle = Rectangle(1, 1)
+        with self.assertRaises(ValueError):
+            _ = box - rectangle
+
+    def test_3d_1d_minus(self):
+        box = Box(1, 1, 1)
+        line = Line((0, 0), (1, 1))
+        with self.assertRaises(ValueError):
+            _ = box - line
+
+    def test_2d_1d_minus(self):
+        rectangle = Rectangle(1, 1)
+        line = Line((0, 0), (1, 1))
+        with self.assertRaises(ValueError):
+            _ = rectangle - line
+
 
 class LocationTests(unittest.TestCase):
     def test_wheel(self):