Compositing with AfterEffects

# 1 26-11-2002 , 07:25 PM

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Join Date: Sep 2002

Location: London, UK

Posts: 3,198

Hi,

I know there's gonna be some VIP tutorials on this but what's been puzzling me is this:

I've batch rendered a simple test animation as an .rla sequence with z-depth on. Basically there are two cubes moving around each other. Each cube is rendered as a separate pass. Now when I composite these two sequences in AE, I should be able to use the z-depth channel info to tell which cube is in front and which is in back, right?

The problem is that I don't know how to set up this in AE. Is this even possible? Or is the whole depth info limited for just creating some DOF and fog effects?

I got the z-depth channel visible with the 3D Channel Extract effect but then I couldn't figure out how to continue...

Kari
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Do a lot, Fail a lot and Learn a lot!

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# 2 27-11-2002 , 01:49 AM

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Join Date: Oct 2002

Location: Australia

Posts: 46

Heres what I'd do...

Im an experienced 3D guy and After Effects user, and this is how I'd achieve what you're after...

If I were doing one object going behind / in front of another, Id just be doing the 'split layer' thing each time they needed to swap.

Effectively, you find a point in your timeline where the objects are not overlapping visually, then select one of the layers (you said the cubes were rendered on seperate passes) and go Edit > Split Layer from the menus.

This will break your layer into two layers. Then, just organise your layer order so that one is behind the other at one point, then behind afterward.
You will need to be careful though - any effects you apply to the split layer will have to be replicated onto the other half of the split layer. Generally, split your layers as a final step, when all fx / transforms are done.

No mucking about with z-depth, just straight RGBA sequences.

Let me know if any of this is unclear and I'll elaborate.

Dan

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# 3 27-11-2002 , 07:42 AM

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dkouts: Thanks for your reply. I understood you technique. So AE can't use the z-depth info to automate this. Can any compositing package do this?

Kari
- My Website
- My IMDB

Do a lot, Fail a lot and Learn a lot!

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# 4 27-11-2002 , 10:24 AM

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Join Date: Oct 2002

Location: Australia

Posts: 46

I dont mean to say After Effects CANT use z-depth info, just that I never have.

Try doing a search in the AE online help docs for "z-depth"

You should be able to get the info you need within AE.

Dan

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