I have a logo which is text that's a photoshop file with a transparent background which of course AE treats as a matte. perfect. now I want to take the fill in the letters (it's a bunch of color blocks) and have them grow inside the text. In an AVID I would just separate out the fill and do a move on it. How do I accomplish this in AE?
I would use the letters layer as a track matte. Bring the fill in as a full-screen image (or higher res than that if you're going to want the blocks to grow a lot). Place the letters on the layer above the fill. Switch on "track matte alpha" on the fill layer and scale the fill to taste.
that got me the matte but when I try to move the fill the matte moves even though I'm not moving that layer, how do I move the fill?
Parent it to the matte.