Representing a Catmull-Rom spline using NURBs ....

Representing a Catmull-Rom spline using NURBs ....

Post by Robert Speran » Mon, 07 Dec 1992 14:43:57

        Hi everyone.  I was wondering if someone could tell me whether a
Catmull-Rom spline could be represented by an equivalent NURB.  I have a NURB-
based modeller I am writing but I am currently using Catmull-Rom splines for
paths and would like to change hem to NURBs.  If anybody can help, it will
be greatly appreciated.  Thanks.  E-mail replies can be sent to any of the
following addresses:

All mail gets forwarded to the third address.  Thanks again.

        Rob Speranza


Representing a Catmull-Rom spline using NURBs ....

Post by aaron cammarata ` » Tue, 08 Dec 1992 04:08:26

        I tried mailing you at all three addresses you listed, and they all
bounced.  I also can't traceroute to any of the hosts you listed, which
explains why mail bounces.
        About the spline question you had: I'm afriad this is a request, not
an answer.  I'm working on an animation in Renderman, and I'd like
to use splines for camera motion.  You said you're using C-R splines for
paths in your animation, and that sounds like what I need.  I don't really
want to reinvent the wheel, so if you could mail me a copy of your spline
function, I'd REALLY appreciate it.  I need a function to take a 3-D spline
and an integer 0<=t<=1 that will return a point in 3-D along the spline.
                        Thanks in advance,




  B4ILUVU, UCT, RU   |         Anyone who says differently is selling something."
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now say "Ekki ekki ekki patang zoomfoisenhouse..."


1. Catmull-Rom or Hermite Splines Using GL Evaluators


    I'm trying to use the OPenGl evaluator to generate a 3-d surface
that interpolates all my data points.  Consequently, I'm trying to
use either Hermite or Catmull-Rom splines.  
   I need to know how to convert my basis to a Bezier basis (which is
what GL evaluators use).  


Michael J. Sinasac, B.A.Sc.                                  M. Eng. Student
NeuroImaging Lab                        Department of Electrical Engineering
Montreal Neurological Institute                            McGill University



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