question

Getting z-depth AOV passes from Arnold within AE is actually quite simple. Generally I always render either full or half-precision .exr files. If I plan on using them in AE. I never combine the passes into a single multi-channel .exr and always simply render out each AOV as an individual .exr sequence. AE can extract channels from multi-channel .exr files, but it can make things very slow, so individual sequences work better IMHO.

Set up your AOVs as you usually do in Cinema 4D and leave the z-depth setting at its default setting. I’m not going to get into whether anti-aliased or aliased depth passes are better, but for my uses aliased always works better which is default. If you rather have z-depth passes anti-aliased, simply change the Filter Type from closest_filter to gaussian_filter.

Once you’ve rendered out the .exr sequences, import them into AE as you usually would. Set your project to either 16 bit or full 32 bit, either will work, it just depends on how you need or want to work. Now create a new comp using the z-depth AOV sequence that you previously rendered. Don’t worry, it will appear either pure white which is fine… there’s plenty of information in those seeming empty pixels. Now follow the steps listed below:

1. Add a EXtractoR filter to the newly created layer. Effect>3D Channel>EXtratoR. The layer will immediately turn black, which should be expected.
2. Now click on any of the Channel Info colors. This will bring up the dialog that will allow you to assign the correct ‘layer’ to all of the channels.
3. You’ll notice that there’s only one layer labeled Y. I believe this is luminance, but it doesn’t matter… it’s the only one available and it works. So go ahead and assign the Y layer to all the different channels: Red, Green, and Blue. You don’t need to worry about Alpha, it doesn’t make a difference. Now click OK. The layer will now turn pure white again.
4. You’re now you’re ready to adjust your z-depth channel. Find the Black Point spinner in the EXtractoR filter and simply begin raising it by increments of 10 until you get something you’re happy with. The amount will depend on the size of your scene, and in some cases with very small scenes, it can be very sensitive. I’m sure there’s some exact math around this, but I usually simply try to get every object in the scene to be visible within the image and then use a Levels Adjust to exaggerate or subdue the effect.
5. You now have a perfect z-depth sequence to use with your favorite DOF plugin (I’m still using Frischluft after all these years).