BRDF in .cal under illumination maps?

(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

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
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

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
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general