Introducing the pirouette FPV frame for GFPV

Signed-off-by: Arnaud Morin <arnaud.gfpv@mailops.fr>

plate.py

@@ -0,0 +1,173 @@
+# @author Arnaud Morin <arnaud.gfpv@mailops.fr>
+# SPDX-License-Identifier: Apache-2.0
+#
+
+from math import cos, radians, sin
+
+import cadquery as cq
+
+from frame_params import (CF_DENSITY, FIT, TBONE_D, TENON_L, THICKNESS)
+
+
+def _custom_filets(wp, corners, tol=1e-4):
+    """The edges that run through the flat pattern (parallel to Z) at the
+    given (x, y) corners."""
+    picked = []
+    for e in wp.edges().vals():
+        vs = e.Vertices()
+        if len(vs) != 2:
+            continue
+        a, b = vs[0].toTuple(), vs[1].toTuple()
+        if abs(a[0] - b[0]) > 1e-6 or abs(a[1] - b[1]) > 1e-6:
+            continue
+        if any(abs(a[0] - cx) < tol and abs(a[1] - cy) < tol for cx, cy in corners):
+            picked.append(e)
+    return wp.newObject(picked)
+
+
+def _mortises():
+    """(x, y, angle) of the four arm root mortises, in the plate's own frame.
+    angle is the mortise's long axis, which is radial."""
+    return [(25.3 * cos(radians(a)),
+             25.3 * sin(radians(a)), a) for a in (45.0, 135.0, 225.0, 315.0)]
+
+
+def plate():
+    # one quadrant, from the +X axis to the +Y axis
+    quadrant = [
+        (21, 0.0),
+        (15, 7.0),
+        (28.5, 22.9),
+        (13.9, 23.7),
+        (7.5, 20.5),
+        (0.0, 20.5),
+    ]
+    # mirrored across the Y axis (x -> -x) gives quadrant 2, joining quadrant
+    # 1 into the top half -- both ends now sit on the X axis, so mirrorX()
+    # below can close the loop by mirroring that half across it in turn
+    top_half = quadrant + [(-x, y) for x, y in reversed(quadrant)][1:]
+
+    p = (
+        cq.Workplane("XY")
+        .polyline(top_half)
+        .mirrorX()
+        .extrude(THICKNESS)
+    )
+
+    # Filets
+    p = _custom_filets(p, [(21, 0), (-21, 0), (-21, -0), (21, -0)]).fillet(2)
+    p = _custom_filets(p, [(15, 7), (-15, 7), (-15, -7), (15, -7)]).fillet(2)
+    p = _custom_filets(p, [(28.5, 22.9), (-28.5, 22.9), (-28.5, -22.9), (28.5, -22.9)]).fillet(4.5)
+    p = _custom_filets(p, [(13.9, 23.7), (-13.9, 23.7), (-13.9, -23.7), (13.9, -23.7)]).fillet(2)
+    p = _custom_filets(p, [(7.5, 20.5), (-7.5, 20.5), (-7.5, -20.5), (7.5, -20.5)]).fillet(6.5)
+
+    # Add holes for 20x20 FC
+    p = (
+        p.faces(">Z")
+        .workplane()
+        .pushPoints([(10, 10), (-10, 10), (-10, -10), (10, -10)])
+        # Holes are 2.2 to fit 2.0 screws
+        .hole(2.2)
+    )
+
+    # Add holes for 25.5x25.5 FC
+    p = (
+        p.faces(">Z")
+        .workplane()
+        .pushPoints([(18.03, 0), (-18.03, 0), (0, -18.03), (0, 18.03)])
+        # Holes are 2.2 to fit 2.0 screws
+        .hole(2.2)
+    )
+
+    # Add holes for standoff
+    x, y = (14, 20)
+    p = p.faces(">Z").workplane().pushPoints(
+        [(sx * x, sy * y) for sx in (-1.0, 1.0) for sy in (-1.0, 1.0)]
+    ).hole(2.2)
+
+    # Arm mortises
+    length, width = TENON_L + FIT, THICKNESS
+    r = TBONE_D / 2.0
+    hl, hw = length / 2.0, width / 2.0
+    body = (cq.Workplane("XY")
+            .polyline([(-hl, -hw), (hl, -hw), (hl, hw), (-hl, hw)])
+            .close().extrude(THICKNESS))
+    bones = cq.Workplane("XY")
+    for u in (-(hl - r), hl - r):
+        for v in (-hw, hw):
+            bones = bones.moveTo(u, v).circle(r)
+    bones = bones.extrude(THICKNESS)
+
+    for x, y, a in _mortises():
+        # two separate cuts, not one combined cutter -- a compound of the
+        # rectangle plus 4 tangent circles confuses the boolean into leaving
+        # sliver solids behind
+        p = p.cut(body.rotate((0, 0, 0), (0, 0, 1), a).translate((x, y, 0)))
+        p = p.cut(bones.rotate((0, 0, 0), (0, 0, 1), a).translate((x, y, 0)))
+
+    # Triangle cuts to reduce weight
+    cut1 = (
+        cq.Workplane("XY")
+        .polyline([
+            (6.5, -9),
+            (6.5, 9),
+            (1, 0),
+        ]).close()
+        .extrude(THICKNESS)
+        .edges("|Z")
+        .fillet(1.0)
+    )
+    cut2 = (
+        cq.Workplane("XY")
+        .polyline([
+            (9.5, -9),
+            (9.5, 9),
+            (15, 0),
+        ]).close()
+        .extrude(THICKNESS)
+        .edges("|Z")
+        .fillet(1.0)
+    )
+    cut3 = (
+        cq.Workplane("XY")
+        .polyline([
+            (11, 15),
+            (-11, 15),
+            (0, 4),
+        ]).close()
+        .extrude(THICKNESS)
+        .edges("|Z")
+        .fillet(1.0)
+    )
+
+    p = (
+        p.cut(cut1)
+        .cut(cut1.mirror("YZ"))
+    )
+    p = (
+        p.cut(cut2)
+        .cut(cut2.mirror("YZ"))
+    )
+    p = (
+        p.cut(cut3)
+        .cut(cut3.mirror("XZ"))
+    )
+
+    return p
+
+
+result = plate()
+
+assert result.solids().size() == 1, "plate is not one solid"
+
+if "show_object" not in globals():          # running outside CQ-editor
+    def show_object(*args, **kwargs):
+        pass
+
+show_object(result)
+
+
+if __name__ == "__main__":
+
+    v = result.val().Volume()
+    print("plate      mass %.2f g each, %.2f g for two" % (v * CF_DENSITY, 2 * v * CF_DENSITY))