[Radiance-general] Radiance and irradiation

[Lars O. Grobe]

Hi!

> having access to a Linux machine, I am forced to stick to pc.

I do not want to be picky, but you probably mean Windows, not PC here ;-)

> I understand radiance calculates irradiance and then uses a standard 
> conversion factor Kr=179 lumens/watt. Hence it should be possible to use 
> it for solar irradiation calculation as well as for light analysis.
> 
> My question is, how can I display directly watts/m2 instead of lux?

Depends on what you mean by display. The most useful way would be 
falsecolor images. As falsecolor by default multiplies pixel values by 
179 to get from radiometric to photometric units, you must tell it to 
use a multiplier of 1 instead of 179. Than, you most probably have to 
set the scale in a way that you see the irradiances in your image. One 
example, using a scale of 0-5000 and the multiplier 1 (to avoid the 
conversion to lx) would be like this:

falsecolor -i input.hdr -m 1 -s 5000 -l "Watts/m2" > output.hdr

> As well, in order to perform irradiation analysis a sky generated 
> following the perez-all weather model would be more accurate than just 
> using the standardCIE skies supported by gensky. I understand there is 
> an application called gendaylit that does exectly this. From where can I 
> download a windows version?

Sorry but I have no idea wether you can do that.

CU Lars.
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