A method for operating a real-time gesture based interactive system includes: obtaining a sequence of frames of data from an acquisition system; comparing successive frames of the data for portions that change between frames; determining whether any of the portions that changed are part of an interaction medium detected in the sequence of frames of data; defining a 3D interaction zone relative to an initial position of the part of the interaction medium detected in the sequence of frames of data; tracking a movement of the interaction medium to generate a plurality of 3D positions of the interaction medium; detecting movement of the interaction medium from inside to outside the 3D interaction zone at a boundary 3D position; shifting the 3D interaction zone relative to the boundary 3D position; computing a plurality of computed positions based on the 3D positions; and supplying the computed positions to control an application.