V-Ray supports the rendering of caustics effects by using one of the following techniques: photon mapping (New Map mode) or progressive. Alternatively, you can upload a pre-made photon map file.
The Progressive caustics solver uses advanced sampling techniques, and is able to trace as many photons as required without suffering the memory constraints of traditional Photon Mapping techniques.
The other method, Photon Mapping, is a two-pass technique.
Caustics parameters are available in the GI tab of the V-Ray render settings.
UI Text Box
type
tip
Since V-Ray 7, you can render Caustics with V-Ray GPU.
Column
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5%
Column
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40%
...
Fancy Bullets
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circle
they require the progressive image sampler;
this image sampler often requires requires Min. subdivs values much higher than 1;
it's non-deterministic, meaning that there could be somewhat unpredictable render times, and also tiny differences in the visual results when rendering the same frame twice;
currently doesn't work with distributed rendering;currently not supported by the GPU engine;
Depending on the scene, the performance might not scale linearly with the number of threads/cores, resulting in inefficient CPU utilization.
