Hi everybody,
I've created a reflective ring (VEX Metal) and a box below it. Then I generated a caustics map using “Photon Map Generation” rendering engine. When rendering the final image (PBR) using this map there is no caustics reflecting from the ring. But it should be there, right? Can someone tell me what I'm doing wrong, please?

Berija

Caustics are formed when light refracts through a transparent surface, producing patters of focused light on the surface behind it. You can render caustics using photon maps and the physically based rendering algorithm in mantra.

Adding caustics requires two output drivers. One will generate the photon map and the other will render the final image using the generated photon map.

Photon maps will only be generated for point lights and spot lights. If you are using point lights, make sure it is close enough to the scene to ensure that enough photons will hit your transparent geometry. If you are using spot lights, make sure it is illuminating as small an are of your scene as possible. You can do this by adjusting the Cone Angle and Cone Delta parameters on the Spot Light Options sub-tab of the Light tab.

If your render produces the error message: “Aborting photon generation from light…”, try moving your light closer to the scene or fixing the orienting toward your geometry. If the light is too far away from your scene it will not be able to efficiently generate photon maps.

There's a good bit of discussion of caustics and a couple of examples here:
http://forums.odforce.net/index.php?showtopic=6211 [forums.odforce.net]

Thank you for your reply.

Nice example scene of refractive caustics can be found here:
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=9819&highlight=caustic [sidefx.com]