Moving Traffic Blur

[jujubee]

I'm just curious - how do you guys go about superimposing a photograph of a moving car or traffic blurred on top of a rendering? I've seen it a few times and it always looks good.

[duke2]

I think maybe it's painted. A way of doing it though, would be to map the car photo to a plane, and have it animate along a spline over 5 frames or something insane, and render with lots of motion blur and overlay in photoshop.

[PGD]

I've often rendered the car static in the view, then in PS cut and paste only the car onto a new layer and motion blur it

Probably far better ways to do it though