How to combine contour and collision?

vvvv beta general
1

hi,everyone

i saw a interactive work :http://www.youtube.com/watch?v=W-oi75cpnvs&playnext_from=TL&videos=Ty4ocg1XBZk,

and i know vvvv can do like this,
but i cannot make it out,
it’s make me so sad.

so,who can try it,explain how to it?
thank you very much!!!