Here's a quickÂ 10-minute tutorialÂ on how to create good looking caustics usingÂ V-RayÂ without spendingÂ hoursÂ in calculations. The whole concept is pretty simple and the final setup should not take long nor stand on one's way while working on a scene.
First, we have to understandÂ why the heck caustics take so long to calculateÂ (if you want something that looks remotely good). And there's only one word to explain it:Â waste. What most people do is to try to generate caustics using the same lights that light the scene, and that causes a hugeÂ waste oftime. Simply because you don't needÂ V-RayÂ to calculateÂ every single photonÂ a light emits. You only need those thatÂ actually causeÂ the caustic effect (which are the minority, of course).
Then, what if you could calculate just those photons? What if you could simply forget about all the waste and complicate settingsÂ andÂ use your system's resources to calculate only those few to maximum effect? That's the objective of this tutorial.