[Bf-cycles] Volume shaders, mirrors that project light sources

[Brecht Van Lommel]

Hi,

On Thu, Nov 17, 2011 at 8:05 PM, Lucas <wsacul at gmail.com> wrote:
> I don't quite understand why the caustics doesn't work easily if the light
> is passing through parallel glass planes- it seems like as many paths ought
> to make it back from a diffuse bounce to the light source as they do in free
> space, unless some shortcut/'cheating' is helping out with the free space
> path, or the probabilistic path termination is really aggressive after a
> single free space to glass transition.  Can I get correct results (like the
> light source passing through the glass ball
> in http://www.cs.berkeley.edu/~sequin/CS184/TOPICS/GlobalIllumination/Gill_0.html and
> projecting and interesting light pattern on the wall and floor) if I crank
> up the render cycles (going to try it myself but it may take a while).

If Glass IOR is exactly 1, it could indeed do the same as it does for
the Transparent. For other values, this requires a different
algorithm. I think it's good to keep different sampling behavior for
different nodes, suddenly doing something when IOR is 1 is not really
predictable, and it would give strange results when texturing this
input.

I guess you can get the results from that scene, if the light source
is a mesh with an emission shader, it's just going to take a long time
for the noise to clean up.

Brecht.