[Radiance-general] Re: intermediate sky

[Greg Ward]

> From: Francesco Anselmo <anselmo@dream.unipa.it>
>
> My first question is about how Radiance models the intermediate sky.
> I studied the code that generates the sky luminance distributions
> (gensky.c + skygright.cal) and found that the overcast and clear skies
> are modelled according to CIE 110-1994 Technical Report.
> But the intermediate sky hasn't been coded according to the Nakamura, 
> Oki et
> al. sky function (that is the present standard, right?): is it related 
> to
> some previous standard?

Hi Francesco,

I meant to reply to this message earlier, but I forgot.  I also forgot 
where the intermediate sky model I used in gensky came from, but it 
wasn't my idea.  I do recall that there were a few models competing at 
the time -- I wasn't aware that Nakamura, Oki et al was selected as the 
standard.  Can you provide a reference?

At any rate, most people who are interested in more sophisticated sky 
simulations rely on the gendaylit program developed by Jean Brange 
while he was at the ISE in Fribourg.  It may still be found on the 
Radiance website at:

	http://radsite.lbl.gov/radiance/pub/generators/

I don't know if there is a newer version, but if there is, someone 
should tell me so I can update the website copy.

-Greg