[Radiance-general] BRDF in .cal under illumination maps?

[giulio]

I think plastdata works only with light sources (direct light  
calculation).
you do not get reflections of objects and diffuse light.
a trick to overcome this, highly inaccurate, is to bake the diffuse  
light component into objects and use light instead of the actual  
materials....
if you have a dome you may need to use mksource to convert it to a set  
of light sources.
hope it is correct and helps...
G

On 13 Oct 2009, at 09:03, Katja Doerschner wrote:

> (Very sorry for the double posting - I forgot to send from my  
> subscribed email account)
>
>
> Dear Group,
>
> I want to use a parametric BRDF (defined in a .cal file and used in  
> conjunction with plasfunc - see below) together with an hdr  
> illumination map.
>
> However doing that seems to switch off my BRDF calculation and the  
> object looks Lambertian (and not velvety, as it is supposed to).
>
> Does any one have an idea how to solve this problem?
>
> Thanks a lot!
>
> Katja
>
> Here a link to the velvety object under point light source  
> illumination.: http://www.bilkent.edu.tr/~katja/velvet.tiff
>
>
> ----------------------------------------------------------
>
> void plasfunc mirror
> 2 refl surf_lobe.cal
> 0
> 9 1 1 1 1 .1 -1 0 0 1
> # x y z area param Vx Vy Vz
> #(to obtain the view direction)
>
>
> {code extracted from surf_lobe.cal:}
> Vx = -(arg(6) - Px);
> Vy = -(arg(7) - Py);
> Vz = -(arg(8) - Pz);
>
> {3.4 Surface lobe - equation from Pont & tePas 2006}
> refl(x,y,z,area)=(1/PI) * (A5/ ( A5+ (x*Nx+y*Ny+z*Nz)*(Vx*Nx+Vy*Ny 
> +Vz*Nz) ))*A9;
>
>
> Katja Doerschner,
> Assistant Professor,
> Department of Psychology, IISBF, 344
> Bilkent University,
> 06800 Ankara, Turkey
>
> +90 (312) 290 1153 / 3004
> bilkent.edu.tr/~katja
> vision.bilkent.edu.tr
> _______________________________________________
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