[Radiance-general] Spherical sensor

[Minki Sung]

Hi Lars~

I modified the script as follows, because i use just one channel out of RGB
channels.

set N=10000
cnt 10 10 10 $N | rcalc -of -e 'Dz=1-2*($4+rand(.77-.61*recno))/'$N \
              -e 'phi=2*PI*($4+rand(-.10+.39*recno))'/$N \
              -e 'rxy=sqrt(1-Dz*Dz);Dx=rxy*cos(phi);Dy=rxy*sin(phi)' \
              -e 'Ox=$1*.02+0.02;Oy=$2*0.02+0.02;Oz=$3*0.02+0.02' \
              -e '$1=Ox;$2=Oy;$3=Oz;$4=Dx;$5=Dy;$6=Dz' \
      | rtrace -h -ff -oov -ar 256 -as 256 -ad 512 -ab 3 scene.oct \
      | total -if4 -10000 -m \
      | rcalc -e '$1=$1;$2=$2;$3=$3;$4=4*PI*$4' > fluence.dat

I checked appropriate number of rays to trace for some positions and
changes below 1% in results were observed between 10000 and more rays, but
less than 10000 was not desirable. I need to check for all the positions
concerned.

Many thank you~

Best,
Minki

-----------------------------------------------------------------------------------------------------------

Hi Minki!
> I am sorry for my too late response to your kind comment. I read your
> script and it is so helpful. I am using Radiance to calculate
> ultraviolet intensity. So I don't need to convert radiance to
> illuminance, but need to revise the script for multiply points sampling.
> Thank you as always.
The script can do that, you just need to remove the multiplication with
Radiance's assumed luminous efficacy (179) and the color weighting
(R*.265+G*.670+B*.065) in the last line. So let the script end as

(...)
| total -if3 -m

And remove the backslash and the last line. I am assuming that you have
set equal values in all channels (R=G=B in all source, material
definitions).

Unfortunately, especially for small light sources of high intensity, you
must set a rather high sampling density N not to miss out important
sources. The script sends out rays to random directions, other then
Radiance's integrated direct calculation which keeps a list of sources
with known locations to check.

Cheers, Lars.

-- 
Minki Sung, Ph.D.

Building Technology Team
Korea Institute of Construction Technology
TEL.+82-31-9100-586
FAX.+82-31-9100-361
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