Getting Correct Depth Pass from VrayEnvironmentFog

[ericmaslowski]

Hello all,
I'm a bit of a beginner to VRay (mostly Brazil and MR in past) and have enjoyed my experiences thus far. One thing that I've been running into is that I can't get a proper depth pass from EnvironmentFog. Regardless of what range I set it always appears at full intensity (closest to the camera). Attached image showing issue. Is VRay capable of providing a proper depth pass for fog? If not, is there a known work-around? Accurate depth passes are critical for a VFX shot I'm working on now. Thanks!

[instinct]

There is no "correct" depth-pass for participating media. As a single pixel you look at has contributions from many different depths along the camera ray. Unless you can create some deepPixel data that is.

Regards,
Thorsten

[ericmaslowski]

Thanks for the response Thorsten. With FumeFX, which operates on similar volumetric principles as EnvironmentFog, a depth pass is possible (see attached for crude example). It relies on the depth information and the alpha channel of that depth pass to give decent results. I was hoping for something along these lines if VRay was unable to do it in a single render.