We see virtual reality as a promising candidate for the ``ultimate'' human-machine interface technology and also as the most challenging system component of the MOVIE model, playing the role of the global integration and synchronization platform for all major design concepts of the system, including interpretive multiserver networking, preemptive multithreading with the real-time aspects, object-oriented three-dimensional graphics model, and support for high-performance computing. We describe this application area in more detail in Section 17.4.