> > it's not in the compiled windows version because it's a work in
progress, i'm
> > doing some tests writing BRDF stuff (for anisotropic highlights for
example,
> > or to give a local micro-geometry and computes the resulting BRDF) (it
really
> > needs lot of work...)
> >
>
> Interesting, how will it work?  Will you be able to use a function with
> additional parameters for the intersection information or do you have some
> different method in mind?

the idea is : give an object (ex: a union of small aligned cylinders for a
brushed metal, or some kind of grass for velvet etc...) that will represent
the micro-geometry of the surface, then do some ray tracing and average for
different positions of light/viewer with this geometry and a simple model
for light interaction (diffuse+phong+shadow), and try to fit parameters of a
general BRDF model to get those results.
In fact this is the same as using a very small normal modifier except that
it would work without heavy antialiasing, and also could take into account
effects of self-shadowing in the micro-geometry. The problem is that s it s
not easy to find a good general model for BRDF (a 4D function !) which does
not require too much parameters.

M

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