def CreateSpiral(self, fp, a):
m = fp.Profile.Shape.BoundBox.Center # Center of the profile
myNumRot = fp.Rotations
myRadius = m.distanceToLine(fp.Center, fp.Center + fp.Axis)
myGrowth = Growth
myPitch = 1.0
myHeight = myNumRot * myPitch
myAngle = atan(myGrowth / myPitch)
assert myGrowth > 0, u"Growth too small"
assert myNumRot > 0, u"Number of rotations too small"
aPnt = VEC(0.0, 0.0, 0.0)
aDir = VEC(2.0 * pi, myPitch, 0.0)
surf = Part.Cone(aPnt, DIR_Z, 1.0, 0.0)
line = Part.LineSegment(aPnt, aDir)
beg = line.value(0)
end = line.value(aDir.Length * myNumRot)
# calculate end point for conical helix
v = myHeight / cos(myAngle)
u = myNumRot * 2.0 * pi
segm = Part.LineSegment(beg, VEC(u, v, 0))
edgeOnSurf = surf.project(segm)
wire = edgeOnSurf.toShape()
aPlane = Part.Plane(aPnt, DIR_Z)
range = (myNumRot + 1) * myGrowth + 1 + myRadius
aPlane.toShape().project(wire)
return spiral
def testderivatives(self):
def get_dn(surface, u, v):
pos = surface.value(u, v)
v10 = surface.getDN(u, v, 1, 0)
v01 = surface.getDN(u, v, 0, 1)
v11 = surface.getDN(u, v, 1, 1)
return (pos, v10, v01, v11)
cone = Part.Cone()
cone.SemiAngle = 0.2
cone.Radius = 2.0
u, v = (5.0, 5.0)
vp, v1, v2, v3 = get_dn(cone, u, v)
shape = cone.toShape(0, 2*math.pi, 0, 10)
shape = shape.toNurbs()
spline = shape.Face1.Surface
u, v = spline.parameter(vp)
wp, w1, w2, w3 = get_dn(spline, u, v)
self.assertAlmostEqual(vp.distanceToPoint(wp), 0)
self.assertAlmostEqual(v1.getAngle(w1), 0)
self.assertAlmostEqual(v2.getAngle(w2), 0)
self.assertAlmostEqual(v3.getAngle(w3), 0)
