[Radiance-general] 10k lux overcast sky implementation only yields 9177?

[Thomas Bleicher]

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

> 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