Is there any way to generate a greyscale z-depth pass that’s not tied to the DOF settings of the scene camera? This would be a pass that’s tied to fixed distances in the scene, unrelated to where the camera is.
In my specific example I’m working on an outdoor scene of a desert. There’s a structure in the foreground with hills and plants stretching into the distance with mountains and sky in the far distance. I want to add aerial perspective, and the fog effect just isn’t doing it for me. I can use various compositing tools in After Effects to create the effect I want, but I need a z-depth pass that stretches from the camera out to 5 miles or so. I could probably set up the camera’s Rear DOF Blur to create a Depth pass, but what if I wanted to have shallow focus on a foreground object AND generate depth for the entire scene to add my atmospheric effect?
Such separate z-depth info must be stored in the scene somewhere because if I render an RPF with z-depth enabled the resulting RPF file contains the data. I can bring the frame into After Effects and extract that depth channel for post effects. I can also render a separate multi pass for the camera DOF if I want to isolate a foreground object for faking DOF in AE.
So the RPF works, but at a price. At 960x540 the 16-bit RPF file is 21 MB, whereas the identical PNG version is only 2.6MB (with the DOF pass being 189KB).
I also notice that when I bring the RPF into AE I’m getting a lot more buffer information than I specified in the Options setting in C4D. In C4D I only have Z-depth checked for export. But in the project window in After Effects AE says the file contains data for Z-depth, Object ID, UV-coordinates, Normal Vector, Non Clamped RGB, Z coverage.
As a test I tried checking every option in the RPF export, and the file is the same size, and shows the same attributes in AE, as the one where I just had Z-depth selected.
RLA files do the same thing and are also big, around 16MB.
This tutorial features another instance where a fixed-depth z-buffer is required.
The tutorial shows how to add dust hits to a 3D render using Trapcode Particular in After Effects. At about one minute in the author shows how to set up a z-depth pass in Lightwave (with minimum and maximum distances) which can be used in the Z Buffer field in Particular to matte the visibility of the dust particle effects. I see no way in Cinema 4D to generate a comparable pass.
Is there a way to do this? Would this be a feature request?
Marshall Arts Motion Graphics