I am trying to redo something that I did fairly easily in AE but, not knowing Motion very deeply, I'm having trouble with part of it.
I have large photoshop file of a Christmas tree and I want to apply a Sapphire sparkle effect to the star on the top. I then want to make a 3D camera move past the tree into a background image. I know it sounds cheesy but that's Christmas, no!
Try as I might, I am finding it really difficult to get the sparkles to apply to the star and not some other part of the image. I can cut out the star OK with a mask, but when I apply that mask to the mask input of the sparkles effect, it doesn't line up properly. I've tried applying the masked star layer itself as the input but that doesn't seem to produce any effect at all.
I'm slightly confused if it's a layer ordering thing or something to do with the complexity of 3D and the camera view. I still don't quite understand how the equivalent of AE's precomposing works in Motion. It seems difficult to have your masked layer behave as if it is a fresh layer with it's own alpha.