3 ms·
Well, I'd define classic as standard "from camera" outwards. POV Ray does classic (which won't give you what you need as it doesn't handle caustics) or photon
by berkut 13y ago
Well, I'd define classic as standard "from camera" outwards.
POV Ray does classic (which won't give you what you need as it doesn't handle caustics) or photon mapping which will.
Bi-directional path tracing (tracing rays from both the camera and lights in the scene and joining the respective light paths in the middle), and Metropolis Light Transport (a progressive variation of BDPT) are the most accurate, but are often slow to converge to a noise-free result, mainly due to the fact they do handle caustics (reflections of bright light focal patterns) accurately, which introduces noise (over the standard GI noise).
But photon mapping would give reasonable results in a few seconds.
- lutusp 13y ago> Well, I'd define classic as standard "from camera" outwards. Fair enough. I was thinking of optical ray tracing, not graphic ray tracing. In optical ray tracing the point is to analyze the paths of light beams through lenses and from mirrors, not the POV of a camera necessarily. I've been able to get pretty useful optical ray tracing out of Pov-Ray: http://www.arachnoid.com/raytracing/csg.html http://www.arachnoid.com/raytracing/csg.html (note the animation toward the bottom of the page).
- berkut 13y agoYeah, I work in the VFX industry, so I'm a bit biased :) Cool - actually, that would be a lot less computationally expensive (assuming you just modelled the sun as a disc) tracing it backwards without any GI at all. Photon mapping's pretty similar though, you've just got a final gather process at the end of sending out the light rays. The difference is photon mapping records all the hits to all surfaces. If you limited it to specular ones (at least for the first ray bounce) you'd probably have something very similar.
- sampo 13y agoThis is what I tried to say 5 or 6 messages ago, when I first replied to you.