[Radiance-general] Multi spectral rendering

[Andrew Bettison]

Greg,

In your paper to the 2002 Eutographics Workshop on Rendering, you 
compare sRGB and Sharp RGB renderings against a multi-spectral rendering 
at 69 evenly-spaced spectral samples from 380 to 720 nm.  I am curious 
how you made that multi-spectral rendering.  Did you divide the 69 
wavelengths into groups of three and run rpict(1) 23 times?  Or did you 
run rpict(1) 69 times with proportional R, G, and B values?  Or did you 
hack rpict(1) from a 3-band renderer to a 69-band one?

In the first case, wouldn�t there have been issues with gradient 
interpolation, which is calculated using the CIE definition of 
brightness from R, G, and B?  Also adaptive shadow testing?  I am 
currently wrestling with these issues as I have to perform 
multi-spectral renderings of many more than 69 bands from 380 nm to 14 
microns, so the CIE definition of brightness won't do.

--
Andrew Bettison
Acacia Research Pty Ltd