[comp.graphics] Ray/patch intersection

Kessells_SR@cc.curtin.edu.au (09/19/90)

Hi,

	Can someone please tell me where I can find an algorithm for
	finding the intersection of a ray and a Bezier and/or B-Spline
	patch. At the moment my Bezier/ray intersection is approximated
	by aprroximating the Bezier patch with triangles. How accurate is
	such an approximation?


						Thanks

						Paul Vowles

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spencer@eecs.umich.edu (Spencer W. Thomas) (09/20/90)

In article <3632.26f78d3f@cc.curtin.edu.au> Kessells_SR@cc.curtin.edu.au writes:

	   Can someone please tell me where I can find an algorithm for
	   finding the intersection of a ray and a Bezier and/or B-Spline
	   patch. 

You might look at

Lischinski and Gonczarowski, "Improved techniques for ray tracing
parametric surfaces," Visual Computer, Vol 6, No 3, June 1990, pp
134-152.

Besides having an interesting technique, they refer to most of the
other relevant work.

--
=Spencer W. Thomas 		EECS Dept, U of Michigan, Ann Arbor, MI 48109
spencer@eecs.umich.edu		313-936-2616 (8-6 E[SD]T M-F)