As Marc said, you definitely want to investigate not trying to do collision against the higher level of detail unless its absolutely necessary. Break your geometry in a series of bounding primitives that move/animate/etc with the real one (but isn't visible). You will then be able to a) make the collision system visible and see the collisions and such b) reduce the number of computations necessary for the collision check. A ray pick at 20k triangle with few trivial rejects (one giant mesh) isn't a good idea. A ray pick that first hits the chest region (by doing a gross sphere check and trivially throwing out the other pieces) and then does a geometry check against an elipsoid (good for people geometry) will definitely speed up things dramatically with little noticable issues. If you need polygon level accuracy, its going to be unfortunately slow - but if you can cheat a little, but all means do so.
