Smoke is not visible above alpha

[barak_vinner]

Hello friends,
I'm sure someone can point me to the right solution with this issue.

My shadow renders fine when above objects or VRAY plane, but in After Effects it is not visible above the environment alpha:

When I but the AO pass beneath the RGB pass, I can see the smoke properly but a thin white line appears on the edges between alpha and RGB:


Inside Chaos Player it looks great, so I wonder - how can I extract that info without re-rendering the whole sequence?


For reference, these are my Volumetric Render Settings for that smoke:


Thanks in advance!
Barak Vinner

[fixeighted]

It's annoying that AE doesn't comp it properly right away, as CP does, however I discovered that if you set that layer to luminescent premultiply then it should work as expected.

[barak_vinner]

Thanks fixeighted
I'm not sure if you referred to the AO layer, but unfortunately it didn't solve my problem...
Is it something I'm doing wrong?

[fixeighted]

Maybe try a precomp of your render layers as you'd normally blend them, then that lum premultiplied over the bkg.

In my example I was only using the rgba and the method solved the problem.
It wasn't my idea but I luckily found an old article moaning about AE's inability to properly blend this stuff, which provided the solution
https://groups.google.com/g/adobe.af...9Gz0Tfq0?pli=1

[barak_vinner]

Thanks again fixeighted
Unfortunately I didn't manage to figure out how to apply your suggestion in a way that it would eliminate the white 1 px edge.
In the end I've created another Vray plane for the ceiling and both planes met in the horizon.
The smoke rendered perfectly in front of the ceiling plane so problem solved for now, but I do need to figure it out for other, more complex smoke effects.

[georgi.zhekov]

Hey,

Could it be that you rendered the AO pass without using Volumetric Geometry mode for the smoke?

In order to get proper AO pass (assuming you used V-Ray Dirt in an ExtraTex Render element, you will have to use Geometry mode). You can find more about the render elements here - https://docs.chaos.com/display/PHX4M...ements+Support

[barak_vinner]

Thank you georgi.zhekov !
Reading your post, I understand there are few things that I've missed in my workflow.
I will check it out in the following week.