Eyedesyn’s EJ Hassenfratz provides a quick tip for using the Matte Object in Cinema 4D, for the times when you have missed or have forgotten to render a specific object buffer for your scene. By using the Matte Object composite tag, will provide an easy way to create a holdout matte for objects in your scene.
in this Cinema 4D quick tip, I’ll be going over the Matte Object. This feature is crucial for when you realize you accidentally forgot to set an Object Buffer in your scene after you rendered everything
EJ shows an example of how and when you would want to use the Matte Object in Cinema 4D which will provide a handy and simple workflow for creating a matte holdout for re-rendering parts of your scene. EJ notes that using the Matte Object is a better method rather than cheating an object buffer by creating a black and white luminance channeled material, and provides a much quicker way to essentially do the same thing. Check out the tutorial for Using The Matte Object in Cinema 4D When Forgetting to Render an Object Buffer here.