On Tue, 18 May 1999 06:22:22 -0400, TonyB
<ben### [at] panamaphoenixnet> wrote:

It isn't quite that simple.  Many spline types are pretty
interchangeable to create - just drop in a different basis matrix.
Cardinal splines, simple b splines, etc.  Others, like Hermite
splines, involve a relatively minor change in how and in what order
you use the points.  Rational splines involve using four instead of
three coordinates (rational Beziers are in the Superpatch).  This is a
bit more work.  Nonuniform splines such as NURBS really need a whole
different setup.  None of this addresses the problems of intersecting
a given type of spline or patch.  If you want to play with some of
them, it is trivial to write macros to provide points for Cardinal,
Tau, B-splines and a few others that you can use as a sort of poor
man's sphere sweep.  Incidentally, it is possible, if a bit of a PITA,
to produce a set of Bezier patches/splines to emulate the results of
using say, a NURB if you want to go to enough effort.  Another thing
to consider is that you would really need a modeller flexible enough
to support them before most people could reap much benefit.

Jerry Anning
clem "at" dhol "dot" com

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