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Arath
04-29-2001, 06:07 AM
Hello boyz,

does anyone know a site which talk about complex bezier patch? I already wrote bézier line and bézier patch in my engine, but I don't know how I can "concat" two or more patch ! There must be a dependance between some control points of two patchs, no? any help is welcome or source of course !

Arath

jwatte
04-29-2001, 07:41 AM
Yes, there is a dependency between control points if you want no sharp edges. If you fill a checkerboard with bezier patches, you can set the control points for all the black pacthes, and all the white patches are dependent on the black patch values.

I seem to remember an article on gamasutra.com about rendering terrain with bezier patches a long time ago. Perhaps check through their archives?

tsuraan
04-29-2001, 09:11 AM
maybe what you're thinking of is a bezier spline patch? Using this algorithm, you specify spline control points, from which the control points for bezier patches can be found, and from there the patches themselves can be found. Try a google search for "bezier spline patch". It should help.

j
04-29-2001, 12:04 PM
There is a relatively easy way to guarantee continuity between adjacent patches.

Take the corner point where the patches meet, and then put all the control points that are connected to this point in the same plane. Do this for every corner where two or more patches meet, and you will get C1 continuity (normals are continuous).

j