How realize?

how could I realize what happens here in the video under?

http://it.youtube.com/watch?v=XyEAgCAcyyY

how am I able that the contour seen by the block contour interaction with some circumferences that float?
interest me, only the part of the collisions between contour and the circle, has tried with the objects 3D Ode but they was not all right.

some idea?

Read here for the shadow part ;)

And check out how to use the Atractor nodes, so the balls go away from the people. And check out the awesome Tweener patches from Zeh to get some smooth animation.