Hello Please forgive my poor English.
I am not sure if this really works, but how about adding a way to interpolate off-curve points in polar coordinates? The procedure is as follows:
- First convert the x-y coordinates of an off-curve point into angle-radius coordinates with the on-curve point being a pole,
- Then interpolate them (always abs(Δangle) < 180°),
- Then convert them back to x-y.
At least this will avoid creating kinks, I think.
I am sorry if this can not work as I expect it to, or if this topic has already been brought up and deemed to be of no use (I searched and found none).