fix: adapting Arc class constructor order to (start, end, center) (#1196)

Co-authored-by: pyansys-ci-bot <pyansys.github.bot@ansys.com>
Co-authored-by: Kathy Pippert <84872299+PipKat@users.noreply.github.com>

Author: 3 people

doc/changelog.d/1196.fixed.md

@@ -0,0 +1 @@
+fix: adapting ``Arc`` class constructor order to (start, end, center)

src/ansys/geometry/core/sketch/arc.py

@@ -40,12 +40,12 @@ class Arc(SketchEdge):
 
     Parameters
     ----------
-    center : Point2D
-        Center point of the arc.
     start : Point2D
         Starting point of the arc.
     end : Point2D
         Ending point of the arc.
+    center : Point2D
+        Center point of the arc.
     clockwise : bool, default: False
         Whether the arc spans the clockwise angle between the start and end points.
         When ``False`` (default), the arc spans the counter-clockwise angle. When
@@ -55,9 +55,9 @@ class Arc(SketchEdge):
     @check_input_types
     def __init__(
         self,
-        center: Point2D,
         start: Point2D,
         end: Point2D,
+        center: Point2D,
         clockwise: Optional[bool] = False,
     ):
         """Initialize the arc shape."""
@@ -78,7 +78,7 @@ def __init__(
             )
 
         # Store the main three points of the arc
-        self._center, self._start, self._end = center, start, end
+        self._start, self._end, self._center = start, end, center
 
         # Compute the vectors from the center to the start and end points
         to_start_vector = Vector2D.from_points(start, center)
@@ -107,6 +107,11 @@ def end(self) -> Point2D:
         """Ending point of the arc line."""
         return self._end
 
+    @property
+    def center(self) -> Point2D:
+        """Center point of the arc."""
+        return self._center
+
     @property
     def length(self) -> Quantity:
         """Length of the arc."""
@@ -117,11 +122,6 @@ def radius(self) -> Quantity:
         """Radius of the arc."""
         return self._radius
 
-    @property
-    def center(self) -> Point2D:
-        """Center point of the arc."""
-        return self._center
-
     @property
     def angle(self) -> Quantity:
         """Angle of the arc."""
@@ -341,4 +341,4 @@ def from_three_points(cls, start: Point2D, inter: Point2D, end: Point2D):
         is_clockwise = False if angle_s_i < angle_s_e else True
 
         # Finally... you can create the arc
-        return Arc(center=center, start=start, end=end, clockwise=is_clockwise)
+        return Arc(start=start, end=end, center=center, clockwise=is_clockwise)

src/ansys/geometry/core/sketch/gears.py

@@ -142,13 +142,13 @@ def __init__(
             # Now, proceed to draw the arcs and segments
             # TODO: add plane to SketchSegment when available
             self._edges.append(
-                Arc(center=origin, start=outer_arc_start + origin, end=outer_arc_end + origin)
+                Arc(start=outer_arc_start + origin, end=outer_arc_end + origin, center=origin)
             )
             self._edges.append(
                 SketchSegment(start=outer_arc_end + origin, end=inner_arc_start + origin)
             )
             self._edges.append(
-                Arc(center=origin, start=inner_arc_start + origin, end=inner_arc_end + origin)
+                Arc(start=inner_arc_start + origin, end=inner_arc_end + origin, center=origin)
             )
             self._edges.append(
                 SketchSegment(start=inner_arc_end + origin, end=next_outer_arc_start + origin)
@@ -513,19 +513,19 @@ def _generate_arcs(
                 # needed values from the preliminary arc
                 arcs.append(
                     Arc(
-                        center=preliminary_arc.center,
                         start=points[idx],
                         end=points[idx + 1],
+                        center=preliminary_arc.center,
                         clockwise=preliminary_arc.is_clockwise,
                     )
                 )
 
             # Once the loop has finished... extend the last arc
             arcs.append(
                 Arc(
-                    center=preliminary_arc.center,
                     start=points[-2],
                     end=points[-1],
+                    center=preliminary_arc.center,
                     clockwise=preliminary_arc.is_clockwise,
                 )
             )
@@ -537,9 +537,9 @@ def _generate_arcs(
             # Just in case, let us only take the first and last elements of the given list
             arcs.append(
                 Arc(
-                    center=self.origin,
                     start=points[0],
                     end=points[-1],
+                    center=self.origin,
                 )
             )
 

src/ansys/geometry/core/sketch/sketch.py

@@ -414,7 +414,7 @@ def arc(
         Sketch
             Revised sketch state ready for further sketch actions.
         """
-        arc = Arc(center, start, end, clockwise)
+        arc = Arc(start, end, center, clockwise)
         return self.edge(arc, tag)
 
     @check_input_types
@@ -453,7 +453,7 @@ def arc_to_point(
         of the sketch, such as the end point of a previously added edge.
         """
         start = self._single_point_context_reference()
-        arc = Arc(center, start, end, clockwise)
+        arc = Arc(start, end, center, clockwise)
         return self.edge(arc, tag)
 
     def arc_from_three_points(

src/ansys/geometry/core/sketch/slot.py

@@ -120,9 +120,9 @@ def __init__(
         )
 
         # TODO: add plane to SketchSegment when available
-        self._arc1 = Arc(self._arc_1_center, self._slot_corner_1, self._slot_corner_2)
+        self._arc1 = Arc(self._slot_corner_1, self._slot_corner_2, self._arc_1_center)
         self._segment1 = SketchSegment(self._slot_corner_2, self._slot_corner_3)
-        self._arc2 = Arc(self._arc_2_center, self._slot_corner_3, self._slot_corner_4)
+        self._arc2 = Arc(self._slot_corner_3, self._slot_corner_4, self._arc_2_center)
         self._segment2 = SketchSegment(self._slot_corner_4, self._slot_corner_1)
 
         self._edges.append(self._arc1)

tests/integration/test_plotter.py

@@ -563,7 +563,7 @@ def test_visualization_polydata():
     assert polygon.visualization_polydata.n_open_edges == 5
 
     # Test for arc visualization polydata
-    arc = Arc(Point2D([10, 0]), Point2D([10, 10]), Point2D([10, -10]))
+    arc = Arc(Point2D([10, 10]), Point2D([10, -10]), Point2D([10, 0]))
     assert arc.visualization_polydata.center == ([5.0, 0.0, 0.0])
     assert arc.visualization_polydata.bounds == pytest.approx([0.0, 10.0, -10.0, 10.0, 0.0, 0.0])
     assert arc.visualization_polydata.n_faces == 2

tests/test_connection.py

@@ -209,9 +209,9 @@ def test_arc_message_conversion():
     """Test conversion between :class:`Arc <ansys.geometry.core.sketch.arc.Arc>` and
     expected gRPC message type."""
     arc = Arc(
-        Point2D([500, 600], UNITS.mm),
         Point2D([100, 400], UNITS.mm),
         Point2D([900, 800], UNITS.mm),
+        Point2D([500, 600], UNITS.mm),
     )
     grpc_arc_message = sketch_arc_to_grpc_arc(arc, Plane(Point3D([10, 100, 1000], UNITS.mm)))
 
@@ -232,9 +232,9 @@ def test_arc_message_conversion():
     assert grpc_arc_message.axis.z == 1
 
     arc2 = Arc(
-        Point2D([600, 700], UNITS.mm),
         Point2D([200, 500], UNITS.mm),
         Point2D([1000, 900], UNITS.mm),
+        Point2D([600, 700], UNITS.mm),
         True,
     )
     grpc_arc_message2 = sketch_arc_to_grpc_arc(arc2, Plane(Point3D([10, 100, 1000], UNITS.mm)))

tests/test_sketch.py

@@ -700,20 +700,20 @@ def test_arc():
     point_0_m5 = Point2D([0, -5])
 
     with pytest.raises(ValueError, match="Start and end points must be different."):
-        Arc(point_0_0, point_0_5, point_0_5)
+        Arc(point_0_5, point_0_5, point_0_0)
 
     with pytest.raises(ValueError, match="Center and start points must be different."):
-        Arc(point_0_0, point_0_0, point_5_0)
+        Arc(point_0_0, point_5_0, point_0_0)
 
     with pytest.raises(ValueError, match="Center and end points must be different."):
-        Arc(point_0_0, point_0_5, point_0_0)
+        Arc(point_0_5, point_0_0, point_0_0)
 
     with pytest.raises(ValueError, match="The start and end points of the arc are not"):
-        Arc(point_0_0, point_0_5, point_6_0)
+        Arc(point_0_5, point_6_0, point_0_0)
 
     # Let's create a simple arc
-    arc = Arc(point_0_0, point_0_5, point_5_0)
-    arc_2 = Arc(point_0_0, point_0_5, point_5_0)
+    arc = Arc(point_0_5, point_5_0, point_0_0)
+    arc_2 = Arc(point_0_5, point_5_0, point_0_0)
     assert arc == arc_2
     assert not (arc != arc_2)
 
@@ -734,7 +734,7 @@ def test_arc():
     # Validate the PyVista hack for generating the PolyData
     #
     # Needed : 180º arc, counterclockwise
-    arc_180 = Arc(point_0_0, point_0_5, point_0_m5, clockwise=False)
+    arc_180 = Arc(point_0_5, point_0_m5, point_0_0, clockwise=False)
     pd = arc_180.visualization_polydata
 
     # Since the arc is counterclockwise, all X values should be <=0
@@ -744,7 +744,7 @@ def test_arc():
     # Validate the PyVista hack for generating the PolyData
     #
     # Needed : 180º arc, clockwise
-    arc_180 = Arc(point_0_0, point_0_5, point_0_m5, clockwise=True)
+    arc_180 = Arc(point_0_5, point_0_m5, point_0_0, clockwise=True)
     pd = arc_180.visualization_polydata
 
     # Since the arc is clockwise, all X values should be >=0
@@ -792,3 +792,16 @@ def test_polydata_methods():
     assert len(pd) == 2
     assert len(pd_edges) == 1
     assert len(pd_faces) == 1
+
+
+def test_sketch_pyconus2024_voglster_issue1195():
+    """Test sketching unexpected behavior observed in PyConUS 2024 by @voglster."""
+
+    sketch = Sketch()
+    p_start, p_end, p_center = Point2D([1, 0]), Point2D([-1, 0]), Point2D([0, 0])
+    sketch.arc(p_start, p_end, p_center)
+
+    # Check that the arc is correctly defined
+    assert sketch.edges[0].start == p_start
+    assert sketch.edges[0].end == p_end
+    assert sketch.edges[0].center == p_center