Note to users: even when you only want reflection caustics (metals/mirrors) you have to set a IOR value higher than 1, similar to glass materials. The higher, the brighter the caustics. That should be it...
Note to users: even when you only want reflection caustics (metals/mirrors) you have to set a IOR value higher than 1, similar to glass materials. The higher, the brighter the caustics. That should be it...