tw._cycles = cycles
tw._begin_zeta = begin_zeta
tw._axis = np.cross(r0, r1)
- def dirn(tw, theta):
- zeta = tw._begin_zeta + theta * tw._cycles
+ def dirn(tw, theta, extra_zeta=0):
+ zeta = tw._begin_zeta + theta * tw._cycles + extra_zeta
r = tw.radius(theta)
return cos(zeta) * r + sin(zeta) * tw._axis