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How To Render Fog Volume with Alpha Channel

Posted: Mon Mar 29, 2021 7:06 am
by 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!

Re: How To Render Fog Volume with Alpha Channel

Posted: Mon Mar 29, 2021 7:22 am
by 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:
4AF888E9-D08B-4F04-9E68-6D52201ABEA7.jpeg
ciao Beppe

Re: How To Render Fog Volume with Alpha Channel

Posted: Mon Mar 29, 2021 6:30 pm
by PixelEyes
Hi bepeg4d,
Thanks for your reply. That makes sense I will give this a try today.