This might be outdated by now but I had the same issue and just found out how to get it to work.
I'm using Octane for Blender, so I'm not entirely sure the attributes have the same names across platforms. In the Octane environment tab I can add a Medium (which in my case is a Volume Medium), but it also lets me set the Medium Radius
You need to crank up that radius and then adjust (scale or absorption/scattering values) to your liking. Then it will look great!
I've just added a Medium to my Octane Daylight tag and it's working thanks to this post. But it seems like the Medium is now making a reflective surface reflect the alpha checkered background in my Live Viewer? It doesn't render like this, and if I turn off alpha channel the live viewer returns to normal. Does anyone know how I can get the checkerboard to stop appearing when the Scattering Medium is added?
Hi aaronheth, sorry, it is not clear to me if you need or not the alpha channel active. Do you mind to post an image with Alpha channel disabled? ciao beppe
Also for reference, here is the scene with the Alpha Channel but no fog.
Maybe I am misunderstanding how this works, I am just curious why the fog medium makes the checkerboard alpha material show up in reflections in the Live Viewer?