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

[Katja Doerschner]

Thank you very much for the suggestion. I will muddle a bit with it.

Best,
katja
On Oct 13, 2009, at 9:57 PM, giulio wrote:

> 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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