The UnwrapCylCurve script is now working well, using the formula in the previous post, but with a few problems.

Corner points, i.e. angles, between two joined curves cause wiggles, even with high point count. 2000 points is less wiggly than 500 points.
(Tight bends would probably also have wiggles.)

Is there some way to identify corner points?
Separate seems to do it.
Using separate and getStartPoints and getEndPoints may be a work around, with each segment arrayed separately.

The cylinder axis must be parallel with the z_axis.
Only one curve, which can be joined, is done at a time.

- Brian