I have the same need/problem. I am using Unreal to render animation to video, so I don’t need to rely on the real time motion blur that the engine uses. Also, this motion blur tends to generate some unwanted artifacts and in general not to look realistic with very fast moving objects or rotating objects like wheels. I would much rather generate the motion blur in a proper post-processing suite like after effects or nuke. For that to happen I would need to render out a motion vector pass.
I tried to generate a post-processing material but I cant find a way to access the velocity of the vertex. Maybe possible with some custom glsl? Is there a way to do set up a motion vector pass from within the material editor?
Thank you very much.