refactor: Combine Hirth Joint into one class

nhf/checks.py

@@ -0,0 +1,6 @@
+import cadquery as Cq
+
+def binary_intersection(a: Cq.Assembly) -> Cq.Shape:
+    objs = [s.toCompound() for _, s in a.traverse() if isinstance(s, Cq.Assembly)]
+    obj1, obj2 = objs[:2]
+    return obj1.intersect(obj2)

nhf/joints.py

@@ -10,156 +10,165 @@ def hirth_tooth_angle(n_tooth):
     """
     return 360 / n_tooth
 
-def hirth_joint(radius=60,
+@dataclass(frozen=True)
-                radius_inner=40,
+class HirthJoint:
-                base_height=20,
-                n_tooth=16,
-                tooth_height=16,
-                tooth_height_inner=2,
-                tol=0.01,
-                tag_prefix="",
-                is_mated=False):
     """
-    Creates a cylindrical Hirth Joint
+    A Hirth joint attached to a cylindrical base
-
-    is_mated: If set to true, rotate the teeth so they line up at 0 degrees.
-
-    FIXME: The curves don't mate perfectly. See if non-planar lofts can solve
-    this issue.
     """
-    # ensures tangent doesn't blow up
+    radius: float = 60
-    assert n_tooth >= 5
+    radius_inner: float = 40
-    assert radius > radius_inner
+    base_height: float = 20
-    assert tooth_height >= tooth_height_inner
+    n_tooth: float = 16
+    tooth_height: float = 16
+    tooth_height_inner: float = 2
 
-    # angle of half of a single tooth
+    def __post_init__(self):
-    theta = math.pi / n_tooth
+        # Ensures tangent doesn't blow up
+        assert self.n_tooth >= 5
+        assert self.radius > self.radius_inner
+        assert self.tooth_height >= self.tooth_height_inner
 
-    c, s, t = math.cos(theta), math.sin(theta), math.tan(theta)
+    @property
-    span = radius * t
+    def _theta(self):
-    radius_proj = radius / c
+        return math.pi / self.n_tooth
-    span_inner = radius_inner * s
-    # 2 * raise + (inner tooth height) = (tooth height)
-    inner_raise = (tooth_height - tooth_height_inner) / 2
-    # Outer tooth triangle spans 2*theta radians. This profile is the radial
-    # profile projected onto a plane `radius` away from the centre of the
-    # cylinder. The y coordinates on the edge must drop to compensate.
 
-    # The drop is equal to, via similar triangles
+    @property
-    drop = inner_raise * (radius_proj - radius) / (radius - radius_inner)
+    def tooth_angle(self):
-    outer = [
+        return hirth_tooth_angle(self.n_tooth)
-        (span, -tol - drop),
-        (span, -drop),
-        (0, tooth_height),
-        (-span, -drop),
-        (-span, -tol - drop),
-    ]
-    adj = radius_inner * c
-    # In the case of the inner triangle, it is projected onto a plane `adj` away
-    # from the centre. The apex must extrapolate
 
-    # Via similar triangles
-    #
-    #  (inner_raise + tooth_height_inner) -
-    #    (tooth_height - inner_raise - tooth_height_inner) * ((radius_inner - adj) / (radius - radius_inner))
-    apex = (inner_raise + tooth_height_inner)  - \
-        inner_raise * (radius_inner - adj) / (radius - radius_inner)
-    inner = [
-        (span_inner, -tol),
-        (span_inner, inner_raise),
-        (0, apex),
-        (-span_inner, inner_raise),
-        (-span_inner, -tol),
-    ]
-    tooth = (
-        Cq.Workplane('YZ')
-        .polyline(inner)
-        .close()
-        .workplane(offset=radius - adj)
-        .polyline(outer)
-        .close()
-        .loft(ruled=False, combine=True)
-        .val()
-    )
-    angle_offset = hirth_tooth_angle(n_tooth) / 2 if is_mated else 0
-    teeth = (
-        Cq.Workplane('XY')
-        .polarArray(
-            radius=adj,
-            startAngle=angle_offset,
-            angle=360,
-            count=n_tooth)
-        .eachpoint(lambda loc: tooth.located(loc))
-        .intersect(Cq.Solid.makeCylinder(
-            height=base_height + tooth_height,
-            radius=radius,
-        ))
-        .intersect(Cq.Solid.makeCylinder(
-            height=base_height + tooth_height,
-            radius=radius,
-        ))
-        .cut(Cq.Solid.makeCylinder(
-            height=base_height + tooth_height,
-            radius=radius_inner,
-        ))
-    )
-    base = (
-        Cq.Workplane('XY')
-        .cylinder(
-            height=base_height,
-            radius=radius,
-            centered=(True, True, False))
-        .faces(">Z").tag(f"{tag_prefix}bore")
-        .union(teeth.val().move(Cq.Location((0,0,base_height))), tol=tol)
-        .clean()
-    )
-    #base.workplane(offset=tooth_height/2).circle(radius=radius,forConstruction=True).tag("mate")
-    (
-        base
-        .polyline([(0, 0, base_height), (0, 0, base_height+tooth_height)], forConstruction=True)
-        .tag(f"{tag_prefix}mate")
-    )
-    (
-        base
-        .polyline([(0, 0, 0), (1, 0, 0)], forConstruction=True)
-        .tag(f"{tag_prefix}directrix")
-    )
-    return base
 
-def hirth_assembly(n_tooth=12):
+    def generate(self, tag_prefix="", is_mated=False, tol=0.01):
-    """
+        """
-    Example assembly of two Hirth joints
+        is_mated: If set to true, rotate the teeth so they line up at 0 degrees.
-    """
-    #rotate = 180 / 16
 
-    tab = (
+        FIXME: The curves don't mate perfectly. See if non-planar lofts can solve
-        Cq.Workplane('XY')
+        this issue.
-        .box(100, 10, 2, centered=False)
+        """
-    )
+        c, s, t = math.cos(self._theta), math.sin(self._theta), math.tan(self._theta)
-    obj1 = (
+        span = self.radius * t
-        hirth_joint(n_tooth=n_tooth)
+        radius_proj = self.radius / c
-        .faces(tag="bore")
+        span_inner = self.radius_inner * s
-        .cboreHole(
+        # 2 * raise + (inner tooth height) = (tooth height)
-            diameter=10,
+        inner_raise = (self.tooth_height - self.tooth_height_inner) / 2
-            cboreDiameter=20,
+        # Outer tooth triangle spans 2*theta radians. This profile is the radial
-            cboreDepth=3)
+        # profile projected onto a plane `radius` away from the centre of the
-        .union(tab)
+        # cylinder. The y coordinates on the edge must drop to compensate.
-    )
+
-    obj2 = (
+        # The drop is equal to, via similar triangles
-        hirth_joint(n_tooth=n_tooth, is_mated=True)
+        drop = inner_raise * (radius_proj - self.radius) / (self.radius - self.radius_inner)
-        .union(tab)
+        outer = [
-    )
+            (span, -tol - drop),
-    angle = hirth_tooth_angle(n_tooth)
+            (span, -drop),
-    result = (
+            (0, self.tooth_height),
-        Cq.Assembly()
+            (-span, -drop),
-        .add(obj1, name="obj1", color=Role.PARENT.color)
+            (-span, -tol - drop),
-        .add(obj2, name="obj2", color=Role.CHILD.color)
+        ]
-        .constrain("obj1", "Fixed")
+        adj = self.radius_inner * c
-        .constrain("obj1?mate", "obj2?mate", "Plane")
+        # In the case of the inner triangle, it is projected onto a plane `adj` away
-        .constrain("obj1?directrix", "obj2?directrix", "Axis", param=angle)
+        # from the centre. The apex must extrapolate
-        .solve()
+
-    )
+        # Via similar triangles
-    return result
+        #
+        #  (inner_raise + tooth_height_inner) -
+        #    (tooth_height - inner_raise - tooth_height_inner) * ((radius_inner - adj) / (radius - radius_inner))
+        apex = (inner_raise + self.tooth_height_inner)  - \
+            inner_raise * (self.radius_inner - adj) / (self.radius - self.radius_inner)
+        inner = [
+            (span_inner, -tol),
+            (span_inner, inner_raise),
+            (0, apex),
+            (-span_inner, inner_raise),
+            (-span_inner, -tol),
+        ]
+        tooth = (
+            Cq.Workplane('YZ')
+            .polyline(inner)
+            .close()
+            .workplane(offset=self.radius - adj)
+            .polyline(outer)
+            .close()
+            .loft(ruled=False, combine=True)
+            .val()
+        )
+        angle_offset = hirth_tooth_angle(self.n_tooth) / 2 if is_mated else 0
+        h = self.base_height + self.tooth_height
+        teeth = (
+            Cq.Workplane('XY')
+            .polarArray(
+                radius=adj,
+                startAngle=angle_offset,
+                angle=360,
+                count=self.n_tooth)
+            .eachpoint(lambda loc: tooth.located(loc))
+            .intersect(Cq.Solid.makeCylinder(
+                height=h,
+                radius=self.radius,
+            ))
+            .cut(Cq.Solid.makeCylinder(
+                height=h,
+                radius=self.radius_inner,
+            ))
+        )
+        base = (
+            Cq.Workplane('XY')
+            .cylinder(
+                height=self.base_height,
+                radius=self.radius,
+                centered=(True, True, False))
+            .faces(">Z").tag(f"{tag_prefix}bore")
+            .union(
+                teeth.val().move(Cq.Location((0,0,self.base_height))),
+                tol=tol)
+            .clean()
+        )
+        #base.workplane(offset=tooth_height/2).circle(radius=radius,forConstruction=True).tag("mate")
+        (
+            base
+            .polyline([
+                (0, 0, self.base_height),
+                (0, 0, self.base_height + self.tooth_height)
+            ], forConstruction=True)
+            .tag(f"{tag_prefix}mate")
+        )
+        (
+            base
+            .polyline([(0, 0, 0), (1, 0, 0)], forConstruction=True)
+            .tag(f"{tag_prefix}directrix")
+        )
+        return base
+
+    def assembly(self):
+        """
+        Generate an example assembly
+        """
+        tab = (
+            Cq.Workplane('XY')
+            .box(100, 10, 2, centered=False)
+        )
+        obj1 = (
+            self.generate()
+            .faces(tag="bore")
+            .cboreHole(
+                diameter=10,
+                cboreDiameter=20,
+                cboreDepth=3)
+            .union(tab)
+        )
+        obj2 = (
+            self.generate(is_mated=True)
+            .union(tab)
+        )
+        angle = 1 * self.tooth_angle
+        result = (
+            Cq.Assembly()
+            .add(obj1, name="obj1", color=Role.PARENT.color)
+            .add(obj2, name="obj2", color=Role.CHILD.color)
+            .constrain("obj1", "Fixed")
+            .constrain("obj1?mate", "obj2?mate", "Plane")
+            .constrain("obj1?directrix", "obj2?directrix", "Axis", param=angle)
+            .solve()
+        )
+        return result
 
 def comma_joint(radius=30,
                 shaft_radius=10,
@@ -429,10 +438,10 @@ class TorsionJoint:
         spring = self.spring()
         result = (
             Cq.Assembly()
-            .add(spring, name="spring", color=Cq.Color(0.5,0.5,0.5,1))
+            .add(spring, name="spring", color=Role.DAMPING.color)
-            .add(track, name="track", color=Cq.Color(0.5,0.5,0.8,0.3))
+            .add(track, name="track", color=Role.PARENT.color)
             .constrain("track?spring", "spring?top", "Plane")
-            .add(rider, name="rider", color=Cq.Color(0.8,0.8,0.5,0.3))
+            .add(rider, name="rider", color=Role.CHILD.color)
             .constrain("rider?spring", "spring?bot", "Plane")
             .constrain("track?directrix", "spring?directrix_bot", "Axis")
             .constrain("rider?directrix0", "spring?directrix_top", "Axis")

nhf/materials.py

@@ -16,6 +16,7 @@ class Role(Enum):
     # Parent and child components in a load bearing joint
     PARENT = _color('blue4', 0.6)
     CHILD = _color('darkorange2', 0.6)
+    DAMPING = _color('springgreen', 0.5)
     STRUCTURE = _color('gray', 0.4)
     DECORATION = _color('lightseagreen', 0.4)
     ELECTRONIC = _color('mediumorchid', 0.5)

nhf/test.py

@@ -8,12 +8,14 @@ from nhf.checks import binary_intersection
 class TestJoints(unittest.TestCase):
 
     def test_joint_hirth(self):
-        j = nhf.joints.hirth_joint()
+        j = nhf.joints.HirthJoint()
+        obj = j.generate()
         self.assertIsInstance(
-            j.val().solids(), Cq.Solid,
+            obj.val().solids(), Cq.Solid,
             msg="Hirth joint must be in one piece")
     def test_joints_hirth_assembly(self):
-        assembly = nhf.joints.hirth_assembly()
+        j = nhf.joints.HirthJoint()
+        assembly = j.assembly()
         isect = binary_intersection(assembly)
         self.assertLess(isect.Volume(), 1e-6,
                         "Hirth joint assembly must not have intersection")

nhf/touhou/houjuu_nue/__init__.py

@@ -30,10 +30,12 @@ import cadquery as Cq
 import nhf.joints
 import nhf.handle
 from nhf import Material
+from nhf.joints import HirthJoint
+from nhf.handle import Handle
 import nhf.touhou.houjuu_nue.wing as MW
 import nhf.touhou.houjuu_nue.trident as MT
 
-@dataclass(frozen=True)
+@dataclass
 class Parameters:
     """
     Defines dimensions for the Houjuu Nue cosplay
@@ -44,9 +46,9 @@ class Parameters:
 
     # Harness
     harness_thickness: float = 25.4 / 8
-    harness_width = 300
+    harness_width: float = 300
-    harness_height = 400
+    harness_height: float = 400
-    harness_fillet = 10
+    harness_fillet: float = 10
 
     harness_wing_base_pos = [
         ("r1", 70, 150),
@@ -60,36 +62,39 @@ class Parameters:
     # Holes drilled onto harness for attachment with HS joint
     harness_to_root_conn_diam = 6
 
+    hs_hirth_joint: HirthJoint = HirthJoint(
+        radius=30,
+        radius_inner=20,
+        tooth_height=10,
+        base_height=5
+    )
+
     # Wing root properties
     #
     # The Houjuu-Scarlett joint mechanism at the base of the wing
-    hs_joint_base_width = 85
+    hs_joint_base_width: float = 85
-    hs_joint_base_thickness = 10
+    hs_joint_base_thickness: float = 10
-    hs_joint_ring_thickness = 5
+    hs_joint_corner_fillet: float = 5
-    hs_joint_tooth_height = 10
+    hs_joint_corner_cbore_diam: float = 12
-    hs_joint_radius = 30
+    hs_joint_corner_cbore_depth: float = 2
-    hs_joint_radius_inner = 20
+    hs_joint_corner_inset: float = 12
-    hs_joint_corner_fillet = 5
-    hs_joint_corner_cbore_diam = 12
-    hs_joint_corner_cbore_depth = 2
-    hs_joint_corner_inset = 12
 
-    hs_joint_axis_diam = 12
+    hs_joint_axis_diam: float = 12
-    hs_joint_axis_cbore_diam = 20
+    hs_joint_axis_cbore_diam: float = 20
-    hs_joint_axis_cbore_depth = 3
+    hs_joint_axis_cbore_depth: float = 3
 
     # Exterior radius of the wing root assembly
-    wing_root_radius = 40
+    wing_root_radius: float = 40
 
     """
     Heights for various wing joints, where the numbers start from the first joint.
     """
-    wing_r1_height = 100
+    wing_r1_height: float = 100
-    wing_r1_width = 400
+    wing_r1_width: float = 400
-    wing_r2_height = 100
+    wing_r2_height: float = 100
-    wing_r3_height = 100
+    wing_r3_height: float = 100
 
-    trident_handle: nhf.handle.Handle = nhf.handle.Handle(
+    trident_handle: Handle = Handle(
         diam=38,
         diam_inner=33,
         # M27-3
@@ -100,7 +105,7 @@ class Parameters:
     )
 
     def __post_init__(self):
-        assert self.wing_root_radius > self.hs_joint_radius,\
+        assert self.wing_root_radius > self.hs_hirth_joint.radius,\
             "Wing root must be large enough to accomodate joint"
 
 
@@ -174,20 +179,12 @@ class Parameters:
             (-dx, dx),
         ]
 
-    def hs_joint_component(self):
-        hirth = nhf.joints.hirth_joint(
-            radius=self.hs_joint_radius,
-            radius_inner=self.hs_joint_radius_inner,
-            tooth_height=self.hs_joint_tooth_height,
-            base_height=self.hs_joint_ring_thickness)
-        return hirth
-
     def hs_joint_parent(self):
         """
         Parent part of the Houjuu-Scarlett joint, which is composed of a Hirth
         coupling, a cylindrical base, and a mounting base.
         """
-        hirth = self.hs_joint_component().val()
+        hirth = self.hs_hirth_joint.generate()
         #hirth = (
         #    hirth
         #    .faces("<Z")
@@ -231,7 +228,7 @@ class Parameters:
             result
             .faces(">Z")
             .workplane()
-            .union(hirth.move(Cq.Location((0, 0, self.hs_joint_base_thickness))), tol=0.1)
+            .union(hirth.translate((0, 0, self.hs_joint_base_thickness)), tol=0.1)
             .clean()
         )
         result = (
@@ -247,7 +244,12 @@ class Parameters:
         result.faces("<Z").tag("base")
         return result
 
-
+    def wing_root(self) -> Cq.Shape:
+        """
+        Generate the wing root which contains a Hirth joint at its base and a
+        rectangular opening on its side, with the necessary interfaces.
+        """
+        return MW.wing_root(joint=self.hs_hirth_joint)
 
     def wing_r1_profile(self) -> Cq.Sketch:
         """
@@ -288,13 +290,6 @@ class Parameters:
         )
         return result
 
-    def wing_root(self) -> Cq.Shape:
-        """
-        Generate the wing root which contains a Hirth joint at its base and a
-        rectangular opening on its side, with the necessary interfaces.
-        """
-        return MW.wing_root()
-
     ######################
     #    Assemblies      #
     ######################
@@ -310,12 +305,18 @@ class Parameters:
             j = self.hs_joint_parent()
             (
                 result
-                .add(j, name=f"hs_{name}p", color=Material.PLASTIC_PLA.color)
+                .add(j, name=f"hs_{name}", color=Material.PLASTIC_PLA.color)
                 #.constrain(f"harness?{name}", f"hs_{name}p?mate", "Point")
-                .constrain("harness?mount", f"hs_{name}p?base", "Axis")
+                .constrain("harness?mount", f"hs_{name}?base", "Axis")
             )
             for i in range(4):
-                result.constrain(f"harness?{name}_{i}", f"hs_{name}p?h{i}", "Point")
+                result.constrain(f"harness?{name}_{i}", f"hs_{name}?h{i}", "Point")
+        angle = 6 * self.hs_hirth_joint.tooth_angle
+        (
+            result.add(self.wing_root(), name="w0_r1", color=Material.PLASTIC_PLA.color)
+            .constrain("w0_r1?mate", "hs_r1?mate", "Plane")
+            .constrain("w0_r1?directrix", "hs_r1?directrix", "Axis", param=angle)
+        )
         result.solve()
         return result
 

nhf/touhou/houjuu_nue/test.py

@@ -20,7 +20,7 @@ class Test(unittest.TestCase):
         self.assertLess(bbox.zlen, 255, msg=msg)
     def test_wings(self):
         p = M.Parameters()
-        p.wing_r1()
+        p.wing_root()
     def test_harness(self):
         p = M.Parameters()
         p.harness_assembly()

nhf/touhou/houjuu_nue/wing.py

@@ -1,5 +1,10 @@
+"""
+This file describes the shapes of the wing shells. The joints are defined in
+`__init__.py`.
+"""
 import math
 import cadquery as Cq
+from nhf.joints import HirthJoint
 
 def wing_root_profiles(
         base_sweep=150,
@@ -117,7 +122,13 @@ def wing_root_profiles(
         .wires().val()
     )
     return base, middle, tip
-def wing_root():
+
+
+def wing_root(joint: HirthJoint,
+              bolt_diam: int = 12):
+    """
+    Generate the contiguous components of the root wing segment
+    """
     root_profile, middle_profile, tip_profile = wing_root_profiles()
 
     rotate_centre = Cq.Vector(-200, 0, -25)
@@ -175,4 +186,16 @@ def wing_root():
     result = seg1.union(seg2).union(seg3)
     result.faces("<Z").tag("base")
     result.faces(">X").tag("conn")
+
+    j = (
+        joint.generate(is_mated=True)
+        .faces("<Z")
+        .hole(bolt_diam)
+    )
+    result = (
+        result
+        .union(j.translate((0, 0, -10)))
+        .union(Cq.Solid.makeCylinder(57, 5).moved(Cq.Location((0, 0, -10))))
+        .clean()
+    )
     return result