Tutorial: Motion Blur in Crowd

[Captain Jack]

I recently found an awesome tutorial that showed how to have a crowd walking by a stationary subject. The subject was in focus but everybdy walking by would blur. For the life of me I can't find it anymore. If anybody knows of the tutorial that I'm speaking of and could guide me there it woud be much appreciated.

 

[kevinottawa]

If you have a long exposure any moving object will blur and any still object will not.
Like time lapse cars, their lights trail while the street lamps stay sharp.

 

[Captain Jack]

Understood, but there's a tutorial with the exact effect I'm trying to achieve via After Effects.