Other examples of immersion technology include physical environment / immersive space with surrounding digital projections and sound such as the CAVE, and the use of virtual reality headsets for viewing movies, with head-tracking and computer control of the image presented, so that the viewer appears to be inside the scene. The next generation is VIRTSIM, which achieves total immersion through motion capture and wireless head mounted displays for teams of up to thirteen immersants enabling natural movement through space and interaction in both the virtual and physical space simultaneously.