[Sidefx-houdini-list] Anisotropic work around?

Mario Marengo mario at axyzfx.com
Mon Feb 20 14:30:07 EST 2006


On February 20, 2006 01:55 pm, Ivan DeWolf wrote:
> I have altered the MT_brushedmetal shader that you can get of of odforce's
> codex in the renderman rewrites .zip file to handle polygons many times in
> the last several years. You just replace the derivatives (dPdu and dPdv)
> with some vectors that you pass in, and create the vectors on the SOP level
> (same as Marios current thread).
>
> I don't have enough spare time to make simplified production-ready shaders
> that anyone can just use, I put out shaders as source code so they can be
> modified to fit any specific production needs.

Yes, for globally smooth tangents, all you need is a reference space and 
you're done (that's what the code fragment I posted on your SESI forum thread 
does). If, however, you need to guide the anisotropy with some texture map or 
something, then you get into this gradient business that I've been going on 
about in the "UV Gradients" thread. Two slightly different things (yet 
similar in that they both deal with tangents).

I'm also too busy at the moment to make a VOP that you could just drop in, but 
maybe I'll add one to the exchange once things settle down...

Sorry :(

-- 
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Mario Marengo                                  mailto:mario at axyzfx.com
AXYZ ANIMATION                                 http://www.axyzfx.com
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