How To Render Fog Volume with Alpha Channel

[PixelEyes]

Hello everyone! I am trying to render out a scene that has VDB volumes that I would like to keep in the scene. I want to change the background of the Octane Daylight later in Photoshop, so I want to render the scene with the alpha channel on. However, the VDB volumes extend where the background is. When I tried rendering out the scene with alpha channel the VDB volumes flattened and lost all of their depth. Is there a way to export the VDB's on an alpha channel and retain the depth and opacity to them? Thanks for the help!

[bepeg4d]

Hi PixelEyes,
Volume/vdbs are not polygon based, so cannot follow the normal behavior.
You need to use the Beauty/Volume passes if you need to work with Volumes in compositing:

ciao Beppe

[PixelEyes]

Hi bepeg4d,
Thanks for your reply. That makes sense I will give this a try today.