Alpha Channel Background

[Johan]

I want to compose with alpha channel as background, say 50% of the screen. Is there any simple way to do that in AE?

 

[Sol M.]

Re: Alpha Channel Background

Not sure what you're asking here. You want to composite something over a background? Please clarify.

 

[PurposeDriven]

Re: Alpha Channel Background

Do you mean you want the black in Background to have an alpha? In that case... it is already there. Just specify in your Render Que to export rgb+alpha and your NLE will pick it up. May need to render in your NLE as well...

But if that's not what you are looking for, please clarify. ;D

 

[Johan]

Re: Alpha Channel Background

Hi all,
Thanks for replying

I want to compose a ring for example, with alpha channel inside the inner circle, black background outside the outer circle

 

[kai]

Re: Alpha Channel Background

if you're wanting to have (say some footage playing inside a circular shape), you could use track mattes.

 

[Johan]

Re: Alpha Channel Background

Thanks Kai,

I understand it, but what I need is different.
I want to make a composition, with some part consist of alpha channel, then I export as avi.
The reason is that someone else will do the rest on NLE, and I want that they just simply drop the avi to the time line on upper layer to create masking effect.