Hi Michael,

> It's pretty frequent for curvature combs
> to be somewhat misused and over obsessed
> with though - when the comb itself has cusp
> points in it, that is actually G2 continuity,
> that's when the curvature is equal at a juncture point.

I agree with this, I don't really use comb analysis much myself.
I was just trying to point out to Jean-Paul that there was nothing wrong with the curve with the G2 blend that produced seams in the model.

I was trained with all these rules in producing 'technically correct' curves and felt then that it took the gloss off 3d modeling a bit.
There's a definition I like for A-Class surfaces that I came across.

"An A-Class surface is a surface that is smooth and appealing to the eye"

So I figured no matter how the surface was built, as long as it looked smooth and flowing and the reflections were good, it didn't really matter what degree or how many segments and what the comb looked like for the underlying spline.

Cheers