Yes, you can export a frame as a PSD. That will include transparency by default.
Just go to Composition > Save as frame > Photoshop layers.
If you go the same route, but choose "File" instead of "Photoshop layers", it will add an item to the Render Queue, set to export a still image file. You can choose from a number of still image formats, including PSD, PNG, TIFF, etc. Note that in these cases the alpha channel will be available to Photoshop, but not applied directly as transparency. You just need to select the alpha channel in the Channels panel, and create a layer mask from the alpha. Also, it's very important that in the Render Queue you set the Alpha Channel type as Straght/Unmatted, since that's what PS handles better.
All of this is automatic if you save frame as Photshop Layers.
Also, I don't know if this would be useful in your case, but Photoshop Extended (CS3 and CS4) can work wth video files directly. It even has a timeline.
This means you could export a Quicktime file with alpha (using codecs which support transparency, like Animation) and then scrub the file in PS, paint of a frame by frame basis, etc.
You have solved my export to Photoshop issue.
But one issue remains for me. How can I create a composition in AE that begins with a transparent background? I can only find how to make a composition with a solid color background. Knoll Lighting wll be crerating the starbursts...and I can understand how to use the alpha channel back in photoshop...but... I still need to know how to start off with a new solid that is transparent in AE. How do I create a filters layer that is transparent?
I think you are misunderstanding something here. First, the composition as such is transparent. You can verify that by enabling the checkerboard transparency preview at the bottom of the composition viewer window. Since AE is primarily aimed at dealing with video content however, the presence of a fill color for the background is mandatory - 3D programs, other videoprocessing apps and other tools don't use per layer transparency, they use Alpha channels. Therefore the background color is required as a fill color for undefined areas. It is not considered for any processing operations, which you can easily verify by using blending modes. If you switch e.g. to Add and the layer is the only one, it will still look like Normal, because it does not mix with the background color. This also brings us to your next questions: Based on the previous, there is no such thing as transparent layers in AE. You always start out with fully opaque pixels and then use masks, effects and other tools to cut away pieces. For your specific problem, you would simply use Unmult, which comes with KLF to do this based on the luminace of your lens flare. You really just have to get used to it and adapt your way of thinking.
I was kind of wondering about this same issue but in reverse. I have a 3D Sphere in Photoshop that is "rotating" and I'd like to get this into After effects so That I may put only the sphere into an after effects comp. As I try it now, I can only get this into after effects with a black background. I can't seem to figure out what to do. Any help is Greatly appreciated. I've attached a .Mov so you can see what I'm working with. Thank You in advance from the Tenderloin SF!
My default, all PSD files come with transparency automatically, as long as your content has such transparent areas (of course).
The file you posted appears as queued, so maybe you can upload it somewhere else and post the link here?
Are you rendering a video file from Photoshop?
In that case, you have to pick a Quicktime codec which supports transparency.
The Animation codec, for example, famously supports alpha channels.
In fact, when you render a video file from Photoshop Extended, it defauls to the Animation codec set as Million of Colors+ (ie, RGB+Alpha).
If you didn't use the default, when you go to File > Render Video, make sure you choose Quicktime as the format, and press the Settings button.
In the Movie Settings dialog, there's another Settings button. Choose Animation codec, and set "Depth" to "Mllion of Colors+", which means Millions of Colors + the transparency.
Give my regards to Van Ness Ave
I am rendering a video of this 3d object that seems to be spinning. Right now since I haven't been able to get the Earth spinning with transparency behind it, Wait Actually, the .mov that I rendered to your instructions is transparent in After Effects. So when I choose Render Video, chose the RBGA like you said, then at the bottom of the box I choose straight Unmatted, Right? So then in after effects when I import I choose again Unmatted. It works Whoo-Hoo! Thank You So Much for You Wonderfully, Quick and Fantastic Answer!!!!! So here's the link, to the video that I wanted to do and that I can do now thatnks to Adobe and You! http://www.youtube.com/watch?v=nykqFYZu-lU Thanks So Much!!!
You know? Actually, you shouldn't have to render a video file at all.
I think the 3D animation will just work (with transparency and all) if you save a PSD file and import it into After Effects as Composition or Composition - Cropped Layers.
BTW, I saw you video in youtube