If you trying to make low-poly object look like hi-poly, and you know advanced modelling in 3d app like 3ds max, z-brush, mudbox, then u might know, that you can "bake" hipoly geometry on lowpoly mesh.
it's quite simple and easy and produces great results. result of "baking" is often a normal-map or displace map, which cryengine uses well.
i don't see straigh question, but i hope i helped you
google on: "baking hi-poly" or some kind of this