Ryan Snider posts a look into how to create a custom material ID pass in Cinema 4D. If you plan on doing some post work on your C4D renders, you will probably consider creating object buffers, render passes or some other method of post-flexibility.
this 20 minute tut will save you hours of render time, and will teach you skills you will use in every scene you render from now on
These will ultimately allow you to control every element of your rendered scene in After Effects, or your favorite compositor.
Here, Ryan shows how to create a material ID pass in C4D, offering some great tips such as turing anti-aliasing off, and rendering double size instead.
Ryan also walks through creating material ID’s manually, and then shows how you can instantly randomize your material ID colors, which can come in handy of your scenes have a countless number of objects associated with them.
As Ryan mentions, this material ID workflow uses C4D’s built in tools and offers a semi-automated setup, works in every version of C4D, and renders very quickly.
If you are using a 3rd party render engine such as V-Ray, the Material ID workflow may be different. Josef Bsharah talks a bit about using the V-Ray Multimatte and uses Material ID’s expressing the compositing workflow for renders. Check out the post for Creating Material and Object ID’s With VRAYforC4D for that workflow.