[Radiance-general] genBSDF -n option doubt

[Lars O. Grobe]

Hi German,

if you model clear glass, (almost) all transmission is direct. This works very efficient for the glass material type, but in theory requires infinite resolution for a BSDF if you want the models to match. I think there are not many cases where both the BRTDfunc and the glass model as given by Optics make sense, but Optics will not take the decision.

So for anything that you do not have any scatter defined, I'd use glass (dielectric if not thin and to be approximated as one surface).

BRTDfunc output is fine for anything scattering with the limitations of BRTDfunc in the ambient calculation. That is where Window6 comes into play, exporting the BSDF model which is really fully supported by Radiance - though it has a limited resolution.

Cheers, Lars.

> In the other hand; I am trying to see the difference between the BSDF generated when modeling a glazing using the "glass" primitive given by Optics; and the BRTDfunc given by the same program. For now everything suggest that the second one will need much more rays to converge... am I right? 
> 
> I am expecting to see difference in the reflecting part, not in the transmitted part.