TheUMovieGraphRenderPassNodenode defines a render pass that MRQ may produce. This node can be implemented in the graph multiple times, and the exact settings it should use can be created out of a mixture of nodes. Because of this, when rendering, MRQ will figure out how many layers there are that actually use this CDO and will call the function on the CDO once, providing the information about all instances. This will allow the node to create any number of instances (decoupled from the number of times the node is used in the graph).