calculation of shading coefficient with Radiance?

thank you for your reply! How can I change the contents of the channels?

You do not have to "change" them, you must enter the values for any simulation anyway. Define three channels you need, and enter them just as you would do with red green and blue values in their corresponding fields when defining reflection, transmission and emission of your surfaces. Of course you must know the properties of you sources and surface materials for these channels. The point is that in your mind, you have to replace the meaning of the RGB-values, usually taken as RedGreenBlue, with Channel1Channel2Channel3. Colors are just "channels" of radiance in this meaning, so just change the wavelength and you can use it for anything :wink:

Of course as Greg already wrote you should consider if the effects of radiance that are modeled in Radiance are enough or if you need other energy transports for your work, too.

CU Lars.