[Radiance-general] plasfunc

[Greg Ward]

Hi Richard,

What you did wrong is specified a specularity of 0 in your plasfunc:

>     void plasfunc myplastic
>     2 refl mybrdf.cal
>     0
>     4 1 1 1 0

The fourth argument is the fraction of reflected light that is modified 
by your specified BRDF.

-Greg

> From: Richard Murray <rfmurray at sas.upenn.edu>
> Date: February 6, 2005 2:18:38 PM PST
>
> Any advice on using the plasfunc material type?  I've searched the 
> Radiance documentation, digests, etc., and the following was the best 
> I could come up with, but it doesn't seem to work.  Any advice would 
> be welcome.
>
> I think I should be able to define a material like this:
>
>     void plasfunc myplastic
>     2 refl mybrdf.cal
>     0
>     4 1 1 1 0
>
> and then in a file mybrdf.cal, put an arbitrary definition for the 
> BRDF function refl, something like this:
>
>     refl(x,y,z,area) = (x*Nx + y*Ny + z*Nz)^10;
>
> (This isn't actually the form of BRDF I'm interested in.)  Then, I 
> define an object with material myplastic:
>
>     myplastic sphere ball
>     0
>     0
>     4 0 0 .5 .5
>
> When I render this, though (with light sources, other objects, etc. 
> added), the sphere just looks Lambertian.  What am I doing wrong?
>
> Thanks,
>
> Richard