A new taxonomy for locomotion in virtual environments

The concept of virtual reality, although evolving due to technological advances, has always been fundamentally defined as a revolutionary way for humans to interact with computers. The revolution comes from the concept of immersion, which is the essence of virtual reality. Users are no longer passive observers of information, but active participants that have leaped through the computer screen and are now part of the information. This has tremendous implications on how users interact with computer information in the virtual world. Perhaps the most common form of interaction in a virtual environment is locomotion. The term locomotion is used to indicate a user's control of movement through the virtual environment. There are many ways for a user to change his viewpoint in the virtual world. Because virtual reality is a relatively young field, no standard interfaces exist for interaction, particularly locomotion, in a virtual world. There have been few attempts to formally classify the ways in which virtual locomotion can occur. These classification schemes do not take into account the various interaction devices such as joysticks and vehicle mock-ups that are used to perform the locomotion. Nor do they account for the differences in display devices, such as head-mounted displays, monitors, or projected walls. This work creates a new classification system for virtual locomotion methods. The classification provides guidelines for designers of new VR applications, on what types of locomotion are best suited to the requirements of new applications. Unlike previous taxonomies, this work incorporates display devices, interaction devices, and travel tasks, along with identifying two major components of travel: translation and rotation. The classification also identifies important sub-components of these two. In addition, we have experimentally validated the importance of display device and rotation method in this new classification system. This was accomplished through a large-scale user experiment. Users performed an architectural walkthrough of a virtual building. Both objective and subjective measures indicate that choice of display device is extremely important to the task of locomotion, and that for each display device, the choice of rotation method is also important.