[Radiance-general] Using SSLD skies with sun

[Lars O. Grobe]

Hi Phillip!

> So you won't end up with two sun definitions.  And you control the
> diffuse and direct components of global horizontal illuminance.  If
> the sun is not visible, it shouldn't be in the model, the direct
> illuminance component will be zero and the global will equal the
> diffuse illuminance.

Hm, my concern was maybe a bit academic :-) For a sky with a very steep 
gradient, the sun (light) would cover the brightest spot of the sky 
(glow) - so light replaces glow. But because of the altitude 
modification gensky does for high altitudes, the sun (light) is 2.5 
degrees off the brightest spot of the sky glow - leading to light plus 
glow spot. Probably the fact that the solid angle covered by the sun is 
small, the difference is not that high, but in cases where my 
illuminance is really only due to a small circumsolar domain of the sky, 
this may lead to some higher illuminances, right? Would need some test 
models to see whether this becomes visible with a skylight. I just 
realized that I have two different sun positions in my model - the 
'real' one by the ssld background sky, and the manipulated on by gensky.

Yes, I am using you cal-file, thank you by the way :-)

Cheers

Lars.