What unbiased methods give you is certainty. If you leave them long enough
they *will* approach the true solution. The rendering times usually needed
to reduce grain (without post-processing, anyway) are impressively long,
but if you add tweaking and re-rendering time to shift stubborn artefacts
from radiosity, I'm not so sure the comparison is much in POV's favour.

On the other hand, while path tracing et al are nice and all, I'm pretty
sure these methods could *not* be added to POV as it currently is without
massive internal changes. They require sophisticated sampling support for
all render steps to be practical at all. Is the effort worth it?

This thread and others have pointed out that there are actually plenty of
free renderers out there that make unbiased methods their specialty. Why
one more? Programs like PBRT were designed from the ground up to support
multiple approaches to solving the rendering equation, and it shows in the
code. POV wasn't, in fact it's tedious enough to make even minor
alterations to the way it currently works.

Instead I think there is something to be said for sticking to a ray tracer +
global illumination approach. Replacing the existing radiosity method with
something based on photon mapping would help tackle the artefacted GI
problem, but that would be the most major change needed that I can think
of. As a raytracer POV may not be exceptionally fast, but the
(non-commercial) competition I've tried out seem surprisingly slow, and
people still use them. I think there is still demand for fast raytracing
with some occasional GI, why not focus on that?

Tom

Post a reply to this message