数学图形(2.14)Spherical helix曲线

从http://mathworld.wolfram.com/SphericalHelix.html上找到如下一些关于该曲线的说明,不过似乎他的公式和我的脚本完全是两个东西..

The tangent indicatrix of a curve of constant precession is a spherical helix. The equation of a spherical helix on a sphere with radius

making an angle

with the z-axis is

			(1)
			(2)
			(3)

The projection on the

-plane is an epicycloid with radii

			(4)
			(5)

#http://www.mathcurve.com/courbes3d/helicespheric/helicespheric.shtml
vertices = 12000 t = from 0 to (80*PI) k = rand2(0.0, 1) s = sin(t) c = cos(t) a = sin(k*t) b = cos(k*t) r = 10 x = r*(k*c*b - s*a) z = r*(k*s*b + c*a) y = r*sqrt(1 - k*k)*b