[Chris Lunney]

Hmm…

I was worried this might be the case. It would make sense that volume caustics are specific to how the volume of light is effected by a material after it passes through it. Its just simply frustrating that this does not include reflection.

I’ll gladly suggest this to Maxon.

Will have to look into different render engines to see if this is possible.

Is volumetric lighting the only way to achieve this “foggy” effect in C4D. Or is there a way to create an atmosphere of fog in which lights become volumetric?

[Chris Lunney]

Hey Brian,

Thanks for diving into this!

Some more context for ya. I’m working on previs for an installation focused around volumetric lighting. I am specifically interested in seeing the caustic volume the light created and although the surface caustics in the real installation will also inevitably exist, they are not the focus of the work.

Thanks for your pointers on tuning in the rendering for caustics – I used this technique and was able to replicate your look with only surface caustics turned on. After replicating your render, I turned on volume caustics, and got the same issue – The reflected volume does not go beyond the angle bounds of the initial source light. Is it possible this simply hasn’t been built into C4D?

Imagine a rendering of a flashlight in a foggy room. It shines on a mirror. This image would be a beam coming from the flashlight, bouncing off the surface of the mirror, and out at its appropriate angle of reflection, with the reflected beam still appearing to have volume due to the foggy room. A test image of this simple effect is below, with the same problem I experienced initially.