can use the 'different key, as start. not in front of my Shake, not sure if Shake got different key or not. But Quantel Editobox or EQ got it. it can use to pull a key by comparing two picture (static bkg, and bkg with object move). from the shot, you have to get a clean plate first (just before tom hanks up the shot, 1 frame is enough), the use different key to campore it with the shot with tom.
anyway, the key is just the starting, still have to do some hand cleaning of the matte produced by the different key.
thanks
