Someone suggested me to use 2 Kinects at once. Each one is connected with one computer. Instead of fixing it on the ceiling, these are placed on the ground. One is from the front, and another is from the side.
Each one detects only X axe and Y axe, without Z axe (since Kinect does not allow to detect an accurate depth). The two computers communicate with ex. OSC, and the combination of data would be X, Y and Z for the real space.
It is only the idea, though. I know it is not the scope of Arduino Forum, but any ideas or any suggestions?