September 13th, 2007,08:55 AM
3d tracking apps are used to derive the motion of a camera used to film a scene. what you want to do is called matchmoving. hopefully you know the focal length of the camera, film back of the camera and distance to the hand.
what you want to do is create a new 3d camera and set it to the same parameters as the one that filmed the scene. once you have that, you can create 3d geometry that matches the shape of the arm/hand and animate it accordingly. if you only need the wrist area (bare skin), an easy way to do this would be to create several nurbs circles and loft them