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| from math import acos |
|
|
| import FreeCAD, Part |
| from FreeCAD import Base |
| from . import involute |
|
|
| rotate = involute.rotate |
|
|
|
|
| def makeGear(m, Z, angle, split=True): |
| if FreeCAD.ActiveDocument is None: |
| FreeCAD.newDocument("Gear") |
| doc = FreeCAD.ActiveDocument |
| w = FCWireBuilder() |
| involute.CreateExternalGear(w, m, Z, angle, split) |
| gearw = Part.Wire([o.toShape() for o in w.wire]) |
| gear = doc.addObject("Part::Feature", "Gear") |
| gear.Shape = gearw |
| return gear |
|
|
|
|
| class FCWireBuilder(object): |
| """A helper class to prepare a Part.Wire object""" |
|
|
| def __init__(self): |
| self.pos = None |
| self.theta = 0.0 |
| self.wire = [] |
|
|
| def move(self, p): |
| """set current position""" |
| self.pos = Base.Vector(*p) |
|
|
| def line(self, p): |
| """Add a segment between self.pos and p""" |
| p = rotate(p, self.theta) |
| end = Base.Vector(*p) |
| self.wire.append(Part.LineSegment(self.pos, end)) |
| self.pos = end |
|
|
| def arc(self, p, r, sweep): |
| """ "Add an arc from self.pos to p which radius is r |
| sweep (0 or 1) determine the orientation of the arc |
| """ |
| p = rotate(p, self.theta) |
| end = Base.Vector(*p) |
| mid = Base.Vector(*(midpoints(p, self.pos, r)[sweep])) |
| self.wire.append(Part.Arc(self.pos, mid, end)) |
| self.pos = end |
|
|
| def curve(self, *points): |
| """Add a Bezier curve from self.pos to points[-1] |
| every other points are the control points of the Bezier curve (which |
| will thus be of degree len(points) ) |
| """ |
| points = [Base.Vector(*rotate(p, self.theta)) for p in points] |
| bz = Part.BezierCurve() |
| bz.setPoles([self.pos] + points) |
| self.wire.append(bz) |
| self.pos = points[-1] |
|
|
| def close(self): |
| pass |
|
|
|
|
| def midpoints(p1, p2, r): |
| """A very ugly function that returns the midpoint of a p1 and p2 |
| on the circle which radius is r and which pass through p1 and |
| p2 |
| |
| Return the 2 possible solutions |
| """ |
| vx, vy = p2[0] - p1[0], p2[1] - p1[1] |
| b = (vx**2 + vy**2) ** 0.5 |
| v = (vx / b, vy / b) |
| cosA = b**2 / (2 * b * r) |
| A = acos(cosA) |
|
|
| vx, vy = rotate(v, A) |
| c1 = (p1[0] + r * vx, p1[1] + r * vy) |
| m1x, m1y = ((p1[0] + p2[0]) / 2 - c1[0], (p1[1] + p2[1]) / 2 - c1[1]) |
| dm1 = (m1x**2 + m1y**2) ** 0.5 |
| m1x, m1y = (c1[0] + r * m1x / dm1, c1[1] + r * m1y / dm1) |
| m1 = (m1x, m1y) |
|
|
| vx, vy = rotate(v, -A) |
| c2 = (p1[0] + r * vx, p1[1] + r * vy) |
| m2x, m2y = ((p1[0] + p2[0]) / 2 - c2[0], (p1[1] + p2[1]) / 2 - c2[1]) |
| dm2 = (m2x**2 + m2y**2) ** 0.5 |
| m2x, m2y = (c2[0] + r * m2x / dm2, c2[1] + r * m2y / dm2) |
| m2 = (m2x, m2y) |
|
|
| return m1, m2 |
|
|
