Merge pull request #311 from CadQuery/adam-urbanczyk-helix-fix

Helix fix

cadquery/occ_impl/shapes.py

@@ -1030,7 +1030,7 @@ class Wire(Shape, Mixin1D):
         # 3. put it together into a wire
         n_turns = height / pitch
         u_start = geom_line.Value(0.0)
-        u_stop = geom_line.Value(sqrt(n_turns * ((2 * pi) ** 2 + pitch ** 2)))
+        u_stop = geom_line.Value(n_turns * sqrt((2 * pi) ** 2 + pitch ** 2))
         geom_seg = GCE2d_MakeSegment(u_start, u_stop).Value()
 
         e = BRepBuilderAPI_MakeEdge(geom_seg, geom_surf).Edge()

tests/test_cadquery.py

@@ -3348,3 +3348,13 @@ class TestCadQuery(BaseTest):
             part2._findFromEdge()
         with self.assertRaises(RuntimeError):
             part2._findFromEdge(useLocalCoords=True)
+
+    def testMakeHelix(self):
+
+        h = 10
+        pitch = 1.5
+        r = 1.2
+        obj = Wire.makeHelix(pitch, h, r)
+
+        bb = obj.BoundingBox()
+        self.assertAlmostEqual(bb.zlen, h, 1)