Am 12.01.2014 18:54, schrieb MichaelJF:

> I'm not quite sure what we have here. Negative light is a feature which can be
> used artistically, but then the shadows must be affected too. In your additional
> scenes the shadows of the positive light still seems to be not influenced by the
> negative light. Most likely we're hunting down a bug here. My opinion is that
> negative light gives more artistic freedom but then it must be implemented
> correctly. For photorealistic renderings it is not necessary. May be Christoph
> Lipka can shed more light onto this issue.

(I see what you did there :-))

Note that where there is "negative light", there is also "negative 
shadow" - but also note that shadow is nothing but the absence of any 
(in this case negative) light.

The scenes you have posted so far all have the regular shadow lie 
completely inside the "negative shadow", so how should the regular 
shadow be affected by the "negative light"?


Speaking of necessity for photorealistic renderings, negative light 
would play a role if you wanted to simulate light of highly saturated 
colour, such as from LEDs or mercury vapor lights. Such colours are 
outside of the sRGB gamut (or any other RGB gamut, for that matter), and 
would therefore have to be modeled with one or two colour components 
being negative (unless you have spectral rendering available, that is).

I suspect that there are some places within POV-Ray that can't properly 
handle negative colour components though.

Post a reply to this message