VDB alpha

[SergKlyosov]

Hi everyone

How can I produce smoke alpha in Octane for max when rendering VDB from FumeFX to use it for composite?
Material ID, Object ID and Render layer setup didn't help, smoke is invisible in those render passes

Thank you

[Goldisart]

using the alpha material
https://www.youtube.com/watch?v=CWJN7Gfeht0

[SergKlyosov]

Goldisart, thank you for the reply
But can you please describe the technique more detailed?

Спасибо

[Goldisart]

https://yadi.sk/d/Y1ZUfEO03GK2mn

[SergKlyosov]

Goldisart, thank you for sharing the scene
I have downloaded it, but can't figureout how I can achieve alpha of VDB volume in that scene

Maybe here is some misunderstanding. I want to render dust clouds in octane and composite them on top another image in photoshop or similar programs
For example I have a car and light it in two-three lighting passes, like in photography and them composited this shot in PS
After that I want to add dust from tires, so I will render VDB in octane, cut it out and place on top of car image

Right now I have found only one solution: put RGB texture to emission slot of Octane volume and apply diffuse material with black Diffuse to the rest of objects and render black and white image. But it renders insane amount of time

I attached couple images, so you can more clearly understand what I'm talking about

[paride4331]

Hi SergKlyosov,
attached a screenshot about the workflow.
There is an issue with .vdb and object layer ID,
workaround is to assign ID 1 with .vdb
Regards
Paride

[SergKlyosov]

paride4331, thank you a lot! This forkflow completely resolve my issue

Hope in future updates of octane they will implement render ID mask for VDB, so we can render alpha without rendering beauty pass

Cheers!