parameters for dds (rtcontrib) using BSDF material

Hallo,

what is the best parameters for dds.bash when using BSDF materials?

Well, I am testing a simple room with BSDF material ( which i obtained
using windows7beta); but the results are not convincing. it ranges +-20 %
from what i was expecting.

N.B: the parameters i used before for my annual simulations is:

*rtc="-ad 8192 -lw 2e-12 -n $cores" # render-options *( and it works
perfectly with glas material)

···

*
*
thx for your support

--
*N.Nassif

Lighting Designer***
*PLDA Member

Neue Str. 55
21073, Hamburg
Deutschland

+49 162 6050060
[email protected]*

Hi Nassif,
It would be helpful to have more information about your scene and BSDF (and
what is dds.bash??)

I can think of two possible causes of your error:

1 - One of the problems with the Window BSDF data is that they have low
resolution. The averaging of flux over a BSDF patch causes the direct
sunlight to smear. The resulting sun patch is bigger and less bright.
This is illustrated in figures 12 & 13 of this paper:

2 - Using the BSDF material in a daylight coefficient simulation can under
estimate illuminance from direct sun. If your BSDF is for clear glass,
then it should be possible to improve it by setting ss to > 1 (like maybe 8
or 10). I think this works with rtcontrib...

You might also consider generating a high resolution tensor tree BSDF using
genBSDF. It'll definitely help with problem 1, and would help with problem
2 if your BSDF is clear glass.

Regardless though, I'd suggest 3-phase method for anual simulations using
BSDFs. It is much better for non-specular glazing.

Andy

···

On Mon, Jul 16, 2012 at 12:16 AM, nassif nassif <[email protected]> wrote:

Hallo,

what is the best parameters for dds.bash when using BSDF materials?

Well, I am testing a simple room with BSDF material ( which i obtained
using windows7beta); but the results are not convincing. it ranges +-20 %
from what i was expecting.

N.B: the parameters i used before for my annual simulations is:

*rtc="-ad 8192 -lw 2e-12 -n $cores" # render-options *( and it works
perfectly with glas material)
*
*
thx for your support

--
*N.Nassif

Lighting Designer***
*PLDA Member

Neue Str. 55
21073, Hamburg
Deutschland

+49 162 6050060
[email protected]*

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