View Full Version : Combining multiple layers in After Effects

09-22-2005, 05:25 PM
I've created an image sequence of my background which is composed of an aerial, roadways, overpasses, etc., and a TGA image sequence with alpha channel of a train. When I bring them into After Effects, the train moves over the overpass when it should go under. I know why it doesn't look correct, but I'm not sure how to fix it. I'm not sure if it's After Effects fix or a Lightwave fix. If anyone has any suggestions, please pass it on.


09-23-2005, 04:23 AM
I seem to understand just half of what you are saying. I might be able to help if you posted your layers of 1 frame where the problem of the train is.

09-23-2005, 09:11 AM
Let me try better to explain the process. I have multiple LW scene files that I want to compile together using Adobe After Effects. The attached file is the background and if you notice to the right side of the scene, there is a train overcrossing with the train over it. The train should be under the overcrossing, and the only way I can think of doing this is to add the train to my LW background scene. However, I would like to break my scenes apart and compile them into After Effects so that my rendering times are much smaller. The other challenge is shadows. Shadows are not stored in Alpha Channels, or at least I don't know how to incorporate shadows. Any thing you can offer would be helpful.


09-30-2005, 07:24 PM
Since you're not creating the "space" where the image of the train needs to disappear as it goes under the bridge on the train video stream, you need to do it in After Effects. You would do this with masking of the train video stream while it goes under the bridge.

Hope this helps.


10-04-2005, 04:18 AM
If that take is static, I agree with Hoopti, but if it moves, you may want to consider to multipass render the overcrossing and the train as separate passes (independently from your landscape background); then composite your layer in this order: background-train-overcrossing. If you don't want or can't to render it again, you need to track your mask (or to do it by hand).
Also you can render the shadows in alpha channel using shadow_density/alpha_channel/Advanced/Surface_Editor or export it as independent buffer with RenderBufferExport or ASA_Buffer or ExtendedRPF or BufferSaver or maybe even with PS_PSD_Export :)


10-07-2005, 12:39 AM
After Effects is such an amazing software that helps many LW users. I have created this image with more than 16 layers - if I'm not mistaken - about 6 months ago in AE. BTW, one of my friends who lives in Sweden was having the same problem with shadows, but he finally did it as it's been suggested here. Hope you like the pic.

11-03-2005, 01:14 PM
If you render the landscape as RLAs or RPFs (done by adding an image filter under the "processing" effects tab in layout, not in the render options) then you can duplicate the landscape in AE and use 3d channel:ID matte to select individual objects or materials, like your overpass and put them ontop of the train.

11-03-2005, 05:44 PM
RLA approach is wonderful and it works even with animations too, not just static images. It's a great way to create artifical masks simply by addressing the layers within the shot.