Comment by amelius

Wow, the problem is more involved than I (a simple user) realized ...

Maybe I have to broaden my search for a raytracer. What would be my best bet for correctly simulating multi-material lenses (so with physical correctness), in Linux (open source), preferably with GPU support?

(By the way, as a user I'd be happy to give up even a factor of 10 of performance if the resulting rendering was 100% physically accurate)