Paco said:
¿Any one knows any soft for ligthing calculations under Linux?
Artistic rendering no, please, lighting simulation programs.
Since you're specifically asking for simulations, you might
want to check out Rayfront:
http://www.schorsch.com/rayfront/
Rayfront is based on Radiance, which means it offers the best
accuracy for non-trivial spaces that you can currently get.
The goal in designing this program was to make as much of the
power and flexibility of Radiance as possible available to a
wide audience, while still keeping it simple to use. As one
user has said, it grows with you as you learn more tricks.
The product includes executables for Windows and several
unix systems, including Linux. The demo version is currently
only available for Windows, though.
-schorsch
