One of the things about 3D is that there are many, many ways to achieve results, and here is a tip from Hector Bermudez how shows a super simple technique for getting a Depth Pass Matte out of Autodesk Maya and using that pass in Nuke for compositing effects.
In this tutorial i’ll explain a simple way to create a Z Depth pass from maya and composite in Nuke
This is a really “old school” type of trick where essentially you are creating a complete white (ore black) surface for your objects in the scene, and then adding a fog that will act as the “depth” as the opposite color from your objects.
Quite simply, the further your objects are, the more the fog takes over, creating a simple depth pass, essentially manually.
In Hector’s example, he is creating a new render layer with the surface shader in maya for the objects in the scene, and using a volume primitive that will act as the fog in the scene, set to black.
In some cases, this no-mess and uncomplicated technique will offer a quick and alternative way to easily render a depth matte, rather than using the standard buffers.