Peter Star

Please look though your question one extra time before posting, and make sure what you ask is clear and easy to understand. Let's say you want to roto a person. You create a shape for the face, one shape for the hair, one for each arm, one for the torso and a couple of shapes for the feets. If you only use one single MediaOut node (with index number 0), you will only get access to the full roto shape (including face, hair, torso, and feets) in the color tab. So, what If you want to access to the hair only? Because you want to colour it blue? Then you need to connect the roto shape of the hair to a new MediaOut node (with index number 1) If you then create an extra source / input in the color tab you will get access to the roto of the hair.

For every MediaOut node you create it gets a new index number. So the next MediaOut node you create gets the index number 1. The one after that, index number 2. In the color tab you have only one source / input. This corresponds to index number 0. If you add a new source / input in the color tab it corresponds to the index number 1. So the idea is that you can get access to multiple parts of your Fusion composition in the Color tab. Useful for example if you want to bring in different roto masks from your full roto shape and color them separately.