render layer mask
It makes a mask for each object in the scene. This allows you to get the individual render pass of the desired object and control it as you like in Composition Environment. Works like Cinema 4D's native "Object Buffer".
In the scene you see in the picture below, "Layer ID" numbers are assigned to 3 different objects by using "Octane Object Tag". Then in the Render Passes setting, assigned a Layer ID number for each object. When you make a Picture Viewer render, each object's individual matte renderings will be made. You can then use these masks in any compositing software (alpha, luma, blending, track matte etc.).
Info: Render Layer Masks do not appear in Live Viewer. For this you need to render them via Picture Viewer.