Abstract: System for interaction between a computer implemented interactive application and a user (1) located in an interactive zone (2) of said system, said system comprising: a passive object (3) comprising a grasping portion for receiving the hand of a user and a marked portion comprising a distinctive spot (4) having distinct visual property; a depth-aware camera (5); a controller (7) for receiving the images produced by said depth-aware camera (5) and being configured to compute two possibilities for the 3D coordinates of said distinctive spot (4) from the knowledge of (i) the 3D coordinates of the wrist joint (9) of said user, (ii) the 2D coordinates (M,N) of said distinctive spot (4) in a contrast image (6) received from said depth aware camera and of (iii) an estimated distance R between the wrist of the user's hand holding the passive object (3) and the distinctive spot (4) of said passive object (3).