Here's my problem: I'm rendering a splash asset which uses a mirror and polyCut node, and because of that, the topology changes per frame, and so, motion vector output is not possible.
I've found a workaround, if I disable the polycut and mirror node, I can get the motion vector AOV pass to work. I connect the nodes to a switch in the main controller to turn them off. Problem is, I want that switch turned ON for beauty and depth and OFF for motionVector. Is it possible to have the active AOV override a channel value - and I'm trying to do this without splitting into multiple render layers. Thanks!