Vertex manipulation in 3d imported models

Hello, I am wondering is if it is possible to control each vertex of an imported 3d model, and how to accomplish it.

I am also looking for a way to have only the arm of a low poly ninja model clickable, to then manipulate his shoulder into following the mouse in a rotation / swing motion, to slice at an enemy.

Any help is greatly appreciated!

I am also interested by that.

Moreover is it possible to recover the clusters (in xsi. I don’t know how it’s called in other 3d application).

Thanks in advance