Fixed Issue #428, added Joints.location property, improved some joint…

… symbols

src/build123d/joints.py

@@ -61,13 +61,16 @@ class RigidJoint(Joint):
 
     """
 
+    @property
+    def location(self) -> Location:
+        """Location of joint"""
+        return self.parent.location * self.relative_location
+
     @property
     def symbol(self) -> Compound:
         """A CAD symbol (XYZ indicator) as bound to part"""
         size = self.parent.bounding_box().diagonal / 12
-        return Compound.make_triad(axes_scale=size).locate(
-            self.parent.location * self.relative_location
-        )
+        return Compound.make_triad(axes_scale=size).locate(self.location)
 
     def __init__(
         self,
@@ -217,6 +220,11 @@ class RevoluteJoint(Joint):
         ValueError: angle_reference must be normal to axis
     """
 
+    @property
+    def location(self) -> Location:
+        """Location of joint"""
+        return self.parent.location * self.relative_axis.location
+
     @property
     def symbol(self) -> Compound:
         """A CAD symbol representing the axis of rotation as bound to part"""
@@ -226,8 +234,9 @@ def symbol(self) -> Compound:
             [
                 Edge.make_line((0, 0, 0), (0, 0, radius * 10)),
                 Edge.make_circle(radius),
+                Edge.make_line((0, 0, 0), (radius, 0, 0)),
             ]
-        ).move(self.parent.location * self.relative_axis.location)
+        ).move(self.location)
 
     def __init__(
         self,
@@ -292,15 +301,10 @@ def relative_to(
         self._angle = angle
         # Avoid strange rotations when angle is zero by using 360 instead
         angle = 360.0 if angle == 0.0 else angle
-        rotation = Location(
-            Plane(
-                origin=(0, 0, 0),
-                x_dir=self.angle_reference.rotate(self.relative_axis, angle),
-                z_dir=self.relative_axis.direction,
-            )
-        )
         return (
-            self.relative_axis.location * rotation * other.relative_location.inverse()
+            self.relative_axis.location
+            * Rotation(0, 0, angle)
+            * other.relative_location.inverse()
         )
 
 
@@ -325,6 +329,11 @@ class LinearJoint(Joint):
 
     """
 
+    @property
+    def location(self) -> Location:
+        """Location of joint"""
+        return self.parent.location * self.relative_axis.location
+
     @property
     def symbol(self) -> Compound:
         """A CAD symbol of the linear axis positioned relative to_part"""
@@ -336,7 +345,7 @@ def symbol(self) -> Compound:
                 ),
                 Edge.make_circle(radius),
             ]
-        ).move(self.parent.location * self.relative_axis.location)
+        ).move(self.location)
 
     def __init__(
         self,
@@ -496,6 +505,11 @@ class CylindricalJoint(Joint):
 
     # pylint: disable=too-many-instance-attributes
 
+    @property
+    def location(self) -> Location:
+        """Location of joint"""
+        return self.parent.location * self.relative_axis.location
+
     @property
     def symbol(self) -> Compound:
         """A CAD symbol representing the cylindrical axis as bound to part"""
@@ -506,13 +520,9 @@ def symbol(self) -> Compound:
                     (0, 0, self.linear_range[0]), (0, 0, self.linear_range[1])
                 ),
                 Edge.make_circle(radius),
+                Edge.make_line((0, 0, 0), (radius, 0, 0)),
             ]
-        ).move(self.parent.location * self.relative_axis.location)
-
-    # @property
-    # def axis_location(self) -> Location:
-    #     """Current global location of joint axis"""
-    #     return self.parent.location * self.relative_axis.location
+        ).move(self.location)
 
     def __init__(
         self,
@@ -634,6 +644,11 @@ class BallJoint(Joint):
 
     """
 
+    @property
+    def location(self) -> Location:
+        """Location of joint"""
+        return self.parent.location * self.relative_location
+
     @property
     def symbol(self) -> Compound:
         """A CAD symbol representing joint as bound to part"""
@@ -657,7 +672,7 @@ def symbol(self) -> Compound:
                     "Z", radius / 5, align=(Align.CENTER, Align.CENTER)
                 ).locate(circle_z.location_at(0.125) * Rotation(90, 0, 0)),
             ]
-        ).move(self.parent.location * self.relative_location)
+        ).move(self.location)
 
     def __init__(
         self,

src/build123d/topology.py

@@ -8346,6 +8346,12 @@ def relative_to(self, other: Joint) -> Location:
         """Return relative location to another joint"""
         raise NotImplementedError
 
+    @property
+    @abstractmethod
+    def location(self) -> Location:  # pragma: no cover
+        """Location of joint"""
+        raise NotImplementedError
+
     @property
     @abstractmethod
     def symbol(self) -> Compound:  # pragma: no cover

tests/test_joints.py

@@ -30,18 +30,18 @@
 import copy
 import unittest
 
-from build123d.build_enums import CenterOf, GeomType
+from build123d.build_enums import Align, CenterOf, GeomType
 from build123d.build_part import BuildPart
-from build123d.geometry import Axis, Location, Vector, VectorLike
+from build123d.geometry import Axis, Location, Rotation, Vector, VectorLike
 from build123d.joints import (
     BallJoint,
     CylindricalJoint,
     LinearJoint,
     RevoluteJoint,
     RigidJoint,
 )
-from build123d.objects_part import Box, Cylinder, Sphere
-from build123d.topology import Plane, Solid
+from build123d.objects_part import Box, Cone, Cylinder, Sphere
+from build123d.topology import Edge, Plane, Solid
 
 
 class DirectApiTestCase(unittest.TestCase):
@@ -121,7 +121,45 @@ def test_revolute_joint_with_angle_reference(self):
 
         self.assertVectorAlmostEquals(j2.symbol.location.position, (0, 0, 1), 6)
         self.assertVectorAlmostEquals(j2.symbol.location.orientation, (0, 0, 90), 6)
-        self.assertEqual(len(j1.symbol.edges()), 2)
+        self.assertEqual(len(j1.symbol.edges()), 3)
+
+    def test_revolute_joint_absolute_locations(self):
+        b1 = Box(10, 10, 1)
+        b2 = Box(5, 5, 1)
+        j1 = RigidJoint("j1", b1, Location((-4, -4, 0.5)))
+        j2 = RevoluteJoint("j2", b2, Axis((2.5, 2.5, 0), (0, -1, 0)))
+
+        j1.connect_to(j2, angle=0)
+
+        self.assertVectorAlmostEquals(j1.location.position, j2.location.position, 5)
+        self.assertVectorAlmostEquals(
+            j1.location.orientation, j2.location.orientation, 5
+        )
+
+    def test_linear_revolute_joint(self):
+        base = Box(10, 10, 2)
+        arm = Box(2, 1, 2, align=(Align.CENTER, Align.CENTER, Align.MIN))
+
+        base_top_edges = (
+            base.edges().filter_by(Axis.X, tolerance=30).sort_by(Axis.Z)[-2:]
+        )
+        linear_axis = Axis(Edge.make_mid_way(*base_top_edges, 0.33))
+        j1 = LinearJoint(
+            "slot",
+            base,
+            axis=linear_axis,
+            linear_range=(0, base_top_edges[0].length),
+        )
+        j2 = RevoluteJoint("pin", arm, axis=Axis.Z, angular_range=(0, 360))
+
+        j1.connect_to(j2, position=6, angle=60)
+
+        target_location = Rotation(0, 0, 60)
+        target_location.position = linear_axis.position + linear_axis.direction * 6
+        self.assertVectorAlmostEquals(target_location.position, j2.location.position, 5)
+        self.assertVectorAlmostEquals(
+            target_location.orientation, j2.location.orientation, 5
+        )
 
     def test_revolute_joint_without_angle_reference(self):
         revolute_base = Solid.make_cylinder(1, 1)
@@ -277,7 +315,7 @@ def test_cylindrical_joint(self):
         self.assertVectorAlmostEquals(
             j1.symbol.location.orientation, (-180, 0, -180), 6
         )
-        self.assertEqual(len(j1.symbol.edges()), 2)
+        self.assertEqual(len(j1.symbol.edges()), 3)
 
         # Test invalid position
         with self.assertRaises(ValueError):