Updating the CadQuery library again for a mistaken reversion of the sagitta arc changes.

Author: jmwright

Libs/cadquery/.travis.yml

@@ -14,12 +14,12 @@ before_install:
     conda config --set always_yes yes --set changeps1 no;
     conda update -q conda;
     conda info -a;
-    conda create -y -q -n freecad_cq3 -c freecad -c freecad/label/broken -c conda-forge freecad=0.17=py36_11 occt=7.2.0=occt7.2.0_0 python=3.6 pyparsing conda mock coverage codecov;
+    conda create -y -q -n freecad_cq3 -c cadquery -c conda-forge freecad=0.17 python=3.6 pyparsing conda mock coverage codecov;
     source ~/miniconda/bin/activate freecad_cq3;
   else
     sudo add-apt-repository -y ppa:freecad-maintainers/freecad-stable;
     sudo apt-get update -qq;
-    sudo apt-get install -y freecad freecad-doc;
+    sudo apt-get install -y freecad;
     pip install -r requirements-dev.txt;
     pip install travis-sphinx;
     pip install sphinx_rtd_theme;

Libs/cadquery/appveyor.yml

@@ -12,7 +12,7 @@ install:
     - set "PATH=%MINICONDA_DIRNAME%;%MINICONDA_DIRNAME%\\Scripts;%PATH%"
     - conda config --set always_yes yes
     - conda update -q conda
-    - conda create --quiet --name cqtest -c freecad -c freecad/label/broken -c conda-forge python=%PYTHON_VERSION% freecad=0.17=py36_vc14_13 occt=7.2.0 python=3.6 pyparsing mock coverage codecov
+    - conda create --quiet --name cqtest -c cadquery -c conda-forge python=%PYTHON_VERSION% freecad=0.17 python=3.6 pyparsing mock coverage codecov
     - activate cqtest
     - python setup.py install
 

Libs/cadquery/cadquery/cq.py

@@ -1320,17 +1320,77 @@ def threePointArc(self, point1, point2, forConstruction=False):
             provide tangent arcs
         """
 
-        gstartPoint = self._findFromPoint(False)
-        gpoint1 = self.plane.toWorldCoords(point1)
-        gpoint2 = self.plane.toWorldCoords(point2)
+        startPoint = self._findFromPoint(False)
+        point1 = self.plane.toWorldCoords(point1)
+        point2 = self.plane.toWorldCoords(point2)
 
-        arc = Edge.makeThreePointArc(gstartPoint, gpoint1, gpoint2)
+        arc = Edge.makeThreePointArc(startPoint, point1, point2)
 
         if not forConstruction:
             self._addPendingEdge(arc)
 
         return self.newObject([arc])
 
+    def sagittaArc(self, endPoint, sag, forConstruction=False):
+        """
+        Draw an arc from the current point to endPoint with an arc defined by the sag (sagitta).
+
+        :param endPoint: end point for the arc
+        :type endPoint: 2-tuple, in workplane coordinates
+        :param sag: the sagitta of the arc
+        :type sag: float, perpendicular distance from arc center to arc baseline.
+        :return: a workplane with the current point at the end of the arc
+
+        The sagitta is the distance from the center of the arc to the arc base.
+        Given that a closed contour is drawn clockwise;
+        A positive sagitta means convex arc and negative sagitta means concave arc.
+        See "https://en.wikipedia.org/wiki/Sagitta_(geometry)" for more information.
+        """
+
+        startPoint = self._findFromPoint(useLocalCoords=True)
+        endPoint = Vector(endPoint)
+        midPoint = endPoint.add(startPoint).multiply(0.5)
+
+        sagVector = endPoint.sub(startPoint).normalized().multiply(abs(sag))
+        if(sag > 0):
+            sagVector.x, sagVector.y = -sagVector.y, sagVector.x # Rotate sagVector +90 deg
+        else:
+            sagVector.x, sagVector.y = sagVector.y, -sagVector.x # Rotate sagVector -90 deg
+
+        sagPoint = midPoint.add(sagVector)
+
+        return self.threePointArc(sagPoint, endPoint, forConstruction)
+
+    def radiusArc(self, endPoint, radius, forConstruction=False):
+        """
+        Draw an arc from the current point to endPoint with an arc defined by the sag (sagitta).
+
+        :param endPoint: end point for the arc
+        :type endPoint: 2-tuple, in workplane coordinates
+        :param radius: the radius of the arc
+        :type radius: float, the radius of the arc between start point and end point.
+        :return: a workplane with the current point at the end of the arc
+
+        Given that a closed contour is drawn clockwise;
+        A positive radius means convex arc and negative radius means concave arc.
+        """
+
+        startPoint = self._findFromPoint(useLocalCoords=True)
+        endPoint = Vector(endPoint)
+
+        # Calculate the sagitta from the radius
+        length = endPoint.sub(startPoint).Length / 2.0
+        try:
+            sag = abs(radius) - math.sqrt(radius**2 - length**2)
+        except ValueError:
+            raise ValueError("Arc radius is not large enough to reach the end point.")
+
+        # Return a sagittaArc
+        if radius > 0:
+            return self.sagittaArc(endPoint, sag, forConstruction)
+        else:
+            return self.sagittaArc(endPoint, -sag, forConstruction)
+
     def rotateAndCopy(self, matrix):
         """
         Makes a copy of all edges on the stack, rotates them according to the
@@ -1738,7 +1798,14 @@ def close(self):
 
             s = Workplane().lineTo(1,0).lineTo(1,1).close().extrude(0.2)
         """
-        self.lineTo(self.ctx.firstPoint.x, self.ctx.firstPoint.y)
+        endPoint = self._findFromPoint(True)
+        startPoint = self.ctx.firstPoint
+
+        # Check if there is a distance between startPoint and endPoint
+        # that is larger than what is considered a numerical error.
+        # If so; add a line segment between endPoint and startPoint
+        if endPoint.sub(startPoint).Length > 1e-6:
+            self.lineTo(self.ctx.firstPoint.x, self.ctx.firstPoint.y)
 
         # Need to reset the first point after closing a wire
         self.ctx.firstPoint=None
@@ -2080,7 +2147,7 @@ def sweep(self, path, sweepAlongWires=False, makeSolid=True, isFrenet=False, com
         :param path: A wire along which the pending wires will be swept
         :param boolean sweepAlongWires:
             False to create mutliple swept from wires on the chain along path
-            True to create only one solid swept along path with shape following the list of wires on the chain 
+            True to create only one solid swept along path with shape following the list of wires on the chain
         :param boolean combine: True to combine the resulting solid with parent solids if found.
         :param boolean clean: call :py:meth:`clean` afterwards to have a clean shape
         :return: a CQ object with the resulting solid selected.
@@ -2407,7 +2474,7 @@ def _sweep(self, path, sweepAlongWires=False, makeSolid=True, isFrenet=False):
         :param path: A wire along which the pending wires will be swept
         :param boolean sweepAlongWires:
             False to create mutliple swept from wires on the chain along path
-            True to create only one solid swept along path with shape following the list of wires on the chain 
+            True to create only one solid swept along path with shape following the list of wires on the chain
         :return:a FreeCAD solid, suitable for boolean operations
         """
 

Libs/cadquery/examples/FreeCAD/Ex005_Extruded_Lines_and_Arcs.py

@@ -18,14 +18,27 @@
 #     half-way back to the origin in the X direction and 0.5 mm above where
 #     the last line ended at. The arc then ends at (0.0, 1.0), which is 1.0 mm
 #     above (in the Y direction) where our first line started from.
-# 5.  close() is called to automatically draw the last line for us and close
+# 5.  An arc is drawn from the last point that ends on (-0.5, 1.0), the sag of
+#     the curve 0.2 determines that the curve is concave with the midpoint 0.1 mm
+#     from the arc baseline. If the sag was -0.2 the arc would be convex.
+#     This convention is valid when the profile is drawn counterclockwise.
+#     The reverse is true if the profile is drawn clockwise.
+#     Clockwise:        +sag => convex,  -sag => concave
+#     Counterclockwise: +sag => concave, -sag => convex
+# 6.  An arc is drawn from the last point that ends on (-0.7, -0.2), the arc is
+#     determined by the radius of -1.5 mm.
+#     Clockwise:        +radius => convex,  -radius => concave
+#     Counterclockwise: +radius => concave, -radius => convex
+# 7.  close() is called to automatically draw the last line for us and close
 #     the sketch so that it can be extruded.
-# 5a. Without the close(), the 2D sketch will be left open and the extrude
+# 7a. Without the close(), the 2D sketch will be left open and the extrude
 #     operation will provide unpredictable results.
-# 6.  The 2D sketch is extruded into a solid object of the specified thickness.
+# 8.  The 2D sketch is extruded into a solid object of the specified thickness.
 result = cq.Workplane("front").lineTo(width, 0) \
                               .lineTo(width, 1.0) \
                               .threePointArc((1.0, 1.5), (0.0, 1.0)) \
+                              .sagittaArc((-0.5, 1.0), 0.2) \
+                              .radiusArc((-0.7, -0.2), -1.5) \
                               .close().extrude(thickness)
 
 # Displays the result of this script

Libs/cadquery/tests/TestCadQuery.py

@@ -867,6 +867,20 @@ def test2DDrawing(self):
                           r.vertices(selectors.NearestToPointSelector((0.0, 0.0, 0.0)))\
                           .first().val().Y))
 
+        # Test the sagittaArc and radiusArc functions
+        a1 = Workplane(Plane.YZ()).threePointArc((5, 1), (10, 0))
+        a2 = Workplane(Plane.YZ()).sagittaArc((10, 0), -1)
+        a3 = Workplane(Plane.YZ()).threePointArc((6, 2), (12, 0))
+        a4 = Workplane(Plane.YZ()).radiusArc((12, 0), -10)
+
+        assert(a1.edges().first().val().geomType() == "CIRCLE")
+        assert(a2.edges().first().val().geomType() == "CIRCLE")
+        assert(a3.edges().first().val().geomType() == "CIRCLE")
+        assert(a4.edges().first().val().geomType() == "CIRCLE")
+
+        assert(a1.edges().first().val().Length() == a2.edges().first().val().Length())
+        assert(a3.edges().first().val().Length() == a4.edges().first().val().Length())
+
     def testLargestDimension(self):
         """
         Tests the largestDimension function when no solids are on the stack and when there are
@@ -1591,3 +1605,36 @@ def testExtrude(self):
         self.assertTupleAlmostEquals(delta.toTuple(),
                                      (0.,0.,2.*h),
                                      decimal_places)
+
+    def testClose(self):
+        # Close without endPoint and startPoint coincide.
+        # Create a half-circle
+        a = Workplane(Plane.XY()).sagittaArc((10, 0), 2).close().extrude(2)
+
+        # Close when endPoint and startPoint coincide.
+        # Create a double half-circle
+        b = Workplane(Plane.XY()).sagittaArc((10, 0), 2).sagittaArc((0, 0), 2).close().extrude(2)
+
+        # The b shape shall have twice the volume of the a shape.
+        self.assertAlmostEqual(a.val().wrapped.Volume * 2.0, b.val().wrapped.Volume)
+
+        # Testcase 3 from issue #238
+        thickness = 3.0
+        length = 10.0
+        width = 5.0
+
+        obj1 = Workplane('XY', origin=(0, 0, -thickness / 2)) \
+            .moveTo(length / 2, 0).threePointArc((0, width / 2), (-length / 2, 0)) \
+            .threePointArc((0, -width / 2), (length / 2, 0)) \
+            .close().extrude(thickness)
+
+        os_x = 8.0    # Offset in X
+        os_y = -19.5  # Offset in Y
+
+        obj2 = Workplane('YZ', origin=(os_x, os_y, -thickness / 2)) \
+            .moveTo(os_x + length / 2, os_y).sagittaArc((os_x -length / 2, os_y), width / 2) \
+            .sagittaArc((os_x + length / 2, os_y), width / 2) \
+            .close().extrude(thickness)
+
+        # The obj1 shape shall have the same volume as the obj2 shape.
+        self.assertAlmostEqual(obj1.val().wrapped.Volume, obj2.val().wrapped.Volume)