Kinect Can't Detect Wrist Movement

[zarx]

if you look at the tech demo's for kinect like this one it is clear why the game doesn't detect wrist "spin"

http://www.nextgn.com/2010/04/15/this-is-how-project-natal-camera-sees-the-player-shaky-cam-video/

Kinect only "sees" a depth map, a contrast/colour map and from that it uses shape recognition to generate a "skeleton" in 3D space. it can't see things like we do, it only "sees" a 3D stick figure and the hand is just a point off the wrist (and a silhouette of course). so as far as I can tell there is no accurate way for a game to detect the twist of the arm.