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Tri patch theory

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Hi guys, I''m looking for some docs, tutorials, source codes ... that could help me start with tri patches. At that time, I''ve already worked on quad patches, but things look different for tri patches, so I only need infos for TRI PATCHES.

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Well, I just tackled tripatches myself, and have got them working. The details of implementation are a bit trickier than with quad patches. My reference was Dave Eberly''s book ''3D Game Engine Design''. p. 297 has a theoretical discussion, and p. 322 has some pseudocode showing how to step through parametrically and evaluate the patch.

I''ve found countless references on quad patches, but that''s the only reference on tri patches I can think of. In any case, it''s a good book to have.

Let us know if you have any more questions.

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Thx for your help jyk, that was exactly what I was looking for.
Indeed, tri patches are very bad known...
One last question before I get that book : can a tri patch be traversed the same way you do with a quad, using 2 parameters ? Or is it trickier ? Maybe by limiting the parameter fields ?

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BTW you can always just cut your tris up into 3 quads of course (See the paper "Watertight tessellation using forward differencing" from Henry Moreton from NVIDIA.) At least assuming you are using cubic patches (it''s probably possible for higher orders too, but I dont think you will find the math in any papers).

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Yes, it can be traversed in 2 dimensions. The parameters are u, v, and w, but u + v + w always = 1, so w always = 1 - u -v. The indexing is a little trickier though, but Eberly''s book explains how to do it.

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