Frame inversion

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 * Added implementation of `RhinoBrep.fillet()` and `RhinoBrep.filleted()` to `compas_rhino`.
+* Added `Frame.invert` and `Frame.inverted`.
 
 ### Changed
 

src/compas/geometry/frame.py

@@ -604,6 +604,18 @@ def to_transformation(self):
     # Methods
     # ==========================================================================
 
+    def invert(self):
+        """Invert the frame while keeping the X axis fixed."""
+        self._yaxis = self.yaxis * -1
+        self._zaxis = None
+
+    def inverted(self):
+        """Return an inverted copy of the frame."""
+        frame = self.copy()  # type: Frame
+        frame.invert()
+        print(frame.xaxis, frame.yaxis, frame.zaxis)
+        return frame
+
     def interpolate_frame(self, other, t):
         """Interpolates between two frames at a given parameter t in the range [0, 1]
 

tests/compas/geometry/test_frame.py

@@ -92,3 +92,35 @@ def test_interpolate_frame_start_end():
 
     three_quarter_frame = frame1.interpolate_frame(frame2, 0.75)
     assert TOL.is_allclose([math.degrees(three_quarter_frame.axis_angle_vector.y)], [-67.5], atol=TOL.angular)
+
+
+def test_frame_invert():
+    frame = Frame([0, 0, 0])
+
+    assert TOL.is_close(frame.xaxis.dot([1, 0, 0]), 1.0)
+    assert TOL.is_close(frame.yaxis.dot([0, 1, 0]), 1.0)
+    assert TOL.is_close(frame.zaxis.dot([0, 0, 1]), 1.0)
+
+    frame.invert()
+
+    assert TOL.is_close(frame.xaxis.dot([1, 0, 0]), 1.0)
+    assert TOL.is_close(frame.yaxis.dot([0, -1, 0]), 1.0)
+    assert TOL.is_close(frame.zaxis.dot([0, 0, -1]), 1.0)
+
+
+def test_frame_inverted():
+    frame = Frame([0, 0, 0])
+
+    assert TOL.is_close(frame.xaxis.dot([1, 0, 0]), 1.0)
+    assert TOL.is_close(frame.yaxis.dot([0, 1, 0]), 1.0)
+    assert TOL.is_close(frame.zaxis.dot([0, 0, 1]), 1.0)
+
+    other = frame.inverted()
+
+    assert TOL.is_close(frame.xaxis.dot([1, 0, 0]), 1.0)
+    assert TOL.is_close(frame.yaxis.dot([0, 1, 0]), 1.0)
+    assert TOL.is_close(frame.zaxis.dot([0, 0, 1]), 1.0)
+
+    assert TOL.is_close(other.xaxis.dot([1, 0, 0]), 1.0)
+    assert TOL.is_close(other.yaxis.dot([0, -1, 0]), 1.0)
+    assert TOL.is_close(other.zaxis.dot([0, 0, -1]), 1.0)