10k lux overcast sky implementation only yields 9177?

Hello Radiance users

I use gensky to create a 10k lux CIE standard overcast sky with the -B command:

gensky 6 1 14 -B 55.866 -c -g 0.2

'-g 0.2' is the default value, so you can omit it. Since you're about to
debug your scene I'd remove everything that's not necessary.

I use the following commands to generate a center line of daylight at working height
(.85m) in a room:

cnt 11 \
> rcalc -e '$1=2;$2=$1/2+.5;$3=.85;$4=0;$5=0;$6=1' \
> rtrace -I -dt 0.03 -ds 0.02 -ab 3 -aa .15 -ar 128 -ad 1024 -as 512 -h -w -oov scene.oct \
> rcalc -e '$1=$2;$2=179*(.265*$4+.670*$5+.065*$6)' > lux.dat

Looks fine to me. Do your values change along the line or are all of them
below 10000? If they differ a lot it's a sign that there is still geometry
left in the scene.

To check the sky I would remove everything from the rtrace command line
except for '-I -ab 1 -h -w -oov' and check a single point for it's value.
Chapter 6 in 'Rendering with Radiance' explains the process step by step.

Another thing:

The man page for gensky shows a sky with non-white glow material. The
'-B 55.866' option will only create a 10k lux sky if you use a normalized
white glow material (r=g=b=1).

HTH,
Thomas

ยทยทยท

On 17 Nov 2007, at 15:26, Christian Anker Hviid wrote: