I'm doing a job at the moment that requires merging live action and cg elements. There's a shot where a cg character has to walk through some long wavey live action grass and I'm trying to figure out a way to use cg grass to mask out the legs of the character. The problem I'm running into is that while vray fur does the job quite well in still images, I can't come up with an effective way to animate it and the forces in max don't have any effect on it. The other option is max grass which can be animate using wind etc but I can't get it to mask out the character's legs because it's just a render effect. Any suggestions?

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