[Vegas] I can't greenscreen properly a smoke

[rocco123]

I generated 3d smoke in a program with a green background to then put this smoke in my animation. I use the chroma keyer and tried playing with the fadders but I just can't get the borders to not be green-ish... any advice?

[poisondeathray]

I generated 3d smoke in a program with a green background to then put this smoke in my animation. I use the chroma keyer and tried playing with the fadders but I just can't get the borders to not be green-ish... any advice?

Can you generate the alpha channel in the 3d program ? (I'm guessing not or you wouldn't be asking...) But that's always better than keying, both in terms of results and speed




I'm guessing what you're describing with the borders is actually "spill" . So you can try to despill the edges . You can post an example to clarify if it's not

There is a spill supression technique using the channel mixer. See this thread, post 10 . Just translate those values to vegas's channel mixer and overlay using "darken". Or you can use something else free like cinegobs , avisynth , etc...
https://forum.videohelp.com/threads/380989-Chaining-calls-to-ColorKeyMask-in-Avisynth

[budwzr]

That's a tough call to troubleshoot. The secret is in the contrast. IOW, how green is your greenscreen. And how sensitive is your editor.

Yes, what PDR says, VegasPro Channel Mixer can help a lot.

What you want to do is push the edges to the limit. Push them to an x-fine edge.

EDIT: If it's spill, thats a different animal. Especially if hair is involved.

[Cornucopia]

The way it is usually done professionally in 3D modeling/rendering/animation apps is that you save an alternate version with no background (must then tweak the environmental/ambient light to compensate), but then do multiple render passes:
1. Composite image
2. Alpha/transparency
3. Highlights/sheen
4. Shadows
5. Depth map
6. Environmental or Lights-only

Then you bring those into the compositing/editing app and layer them (often with different modes) and/or use certain ones of them for mask selection.

Normally when folks come here asking about compositing/alphas/mask selection, they don't have the advantage of having the original 3D app that did the rendering. You do, so you should take full advantage of its features & capabilities.

Scott