Hi Brian,

> So: Is the second derivative at NURBS parameter "t" associated with point on the curve
> <<<Equivalent>>> to the Normal at the point ?

No, but they are related. The curvature vector is calculated from the first and second derivative.


- Michael

Thank's Michael,

Back to vector math calculus class for me :-)

- Brian

Todays idea is to perform a sphere sweep on a curve, using Flow.

Unwrap the curve.
Sphere radii vary along the arc length.
The envelope, for the unwrapped curve (straight line), is a surface of revolution.
The rate of change of the radii equation with arclength to be limited by ?
To get the planar curve to revolve... ???

- Brian