[Radiance-general] Re: Specular Reflections with the Daylight Coefficient Method

[Axel Jacobs]

 > Genskyvec always picks the three closest patches, regardless of
 > the sky resolution.  It would be difficult to use a sky
 > resolution high enough that one patch would be the better choice.
 > I only mentioned the 1-4 range because that's what people have
 > done, not as a recommendation per se.

Including yourself, Greg. Your rtcontutor directory that was in Radiance 
for a while used the four nearest patches. I guess your reasoning to 
reduce this to just three was something like this:

1 - too crude
2 - still only one-dimensional
3 - just perfect. The real sun will always be in the triangle formed by 
exactly three patch centres.
4 - Overkill

So in theory, if you we remove the patch intensity of the sky, we can 
determine the exact position of the sun if the intensity is known, or 
vice versa by triangulation. This is dictated by Greg's Uncertainty 
Principle. Think of it as sub-pixel interpolation in image processing.

Cheers

Axel