calculation of shading coefficient with Radiance?

Hi all!
Sorry for my bad English. I'm a quite new user of Radiance and I'm
interested in energy performance of buildings. I would like to know if
it is possible to calculate the performance of a shading system
(venetian blinds, light shelf, etc.) in terms of reducing solar
radiation. Does Radiance consider all the spectrum in calculating
irradiance? My aim is to try different shading systems in a office
room and to analyse their bahaviour in terms of shading coefficient.
Any help would be appreciated. Thanks in advance,
Valeria