How do you create a transparent background in AE

[Roy Stevens]

Hi--I'm using AE CS5 on a MacBook Pro and I'm brand new to using AE.

How do you create a transparent background?

I need it because I'm creating a shatter effect on a photo and want to import the AE movie into FCP and have it play on one layer while beneath it  another image will be seen when the shatter effect takes place.

He'p me, cap'n!

Thanks!

[Rick Gerard]

Start off by pressing F1 and going to the Transparency and compositing section of the help files. You can find info on the web HERE.

Then move on to the rendering section. You have to pick a codec to render to that supports transparency. The Output Module has a Lossless with Alpha preset that you can use.

Hope this helps.

[Todd_Kopriva]

There are lots of ways to create transparency in After Effects. This page has an overview of the various ways:

"Compositing and transparency overview and resources"

Or are you asking about how to export with an alpha channel? (Your question isn't clear.) If that is the question, then note that you need to choose a format that can include an alpha channel, and you need to specify that the alpha channel is included on output (in the output module settings). This page gives an introduction to alpha channels and lists some formats that can include them:

"About alpha channels and mattes"

[Todd_Kopriva]

It looks like Rick and I were typing at the same time. 😉

[Roy Stevens]

Hey Guys, thanks for your replys!!

Wow, there's a lot to check out there--great!

I hope I'm on the right track, I just watched the video about preserving transparency and maybe I'm stupid, maybe cause I'm new, but I just want to be sure I'm on the right track. Sorry if my question was confusing, maybe cause I am a bit new.

To reiterate: I want to export a short AE movie of a shatter glass effect on a picture. The background needs to be transparent because I will import the AE movie into FCP and place it as the top layer. On a layer beneath it will be video I want to seen as the shatter glass effect creates a 'hole'.

I believe this url tells me how to do that: http://forums.creativecow.net/thread/2/930588

Thanks again!

Elmer