Been messing about recently with Maya render passes to the OpenEXR format, exporting motion vector passes and doing motion blur in post using After Effects. Strangely enough, there appears to really be only one solution for doing motion blur in post with AE. That’s using Reel Smart Motion Blur. I did some tests with the demo version and it works great.
The only big problem I see with the motion vector method is that your shadows don’t get motion blurred and I haven’t quite figured out how to get motion vectors for the shadow pass. For, me that’s the only barrier to really making the process a standard way of doing motion blur. Shadows being sharp while the object blurs is a no go and looks really weird so for now I think I’ll have to stick with Maya motion blur which can be painfully slow.