Atmosphere and Z-Depth Fog

[Russle]

Hello guys,

 

I'm working on a scene with some atmospheric fog. The problem is that I can't find in which render layer the fog goes! It does appear in the beauty, but can't find it anywhere else.

 

My theory is that the z-depth pass is used to create the fog in the beauty and thus I've tried to replicate the fog in comp using this theory. With success I might add.

 

In Nuke if I shuffle out the z-depth, grade it and plus it with (for example) the diffuse (just quick and dirty) the same effect shows. Problem is that I can't recreate the exact same image (as if I would shuffle everything out and in again).

 

I would love to create my own fog shader to output it to a render layer, but I don't have the knowhow. Also Houdini doesn't let me dive into the Z-Depth Fog node for examples.

 

Does anyone know which render layer the fog ends up in? If not can someone give me a quick example of how to create my own simple fog shader?

 

Thank you guys in advance,

 

Russle

 

P.S. Included a simple scene for review.

 

 

 

Z-Depth.hip