[quote=“wim, post:2, topic:93939”]
Hi David - from a presentation that Dale Lear gave us a while back:
Curves that give exact matches when using Loft, ExtrudeCrv, and Revolve to make SubDs are called SubDFriendly.
SubDFriendly curves are:
- NURBS
- degree 3
- uniform
- non-rational
- natural or periodic
[/quote]e
What is the 1/3 - 2/3 rule? If and only if the first three or last three control points are colinear the 2nd derivative is zero independent of the spacing of the control points. Is there another reason the spacing needs to be 1/3 - 2/3?