Seven league boots: A new metaphor for augmented locomotion through moderately large scale immersive virtual environments

When an immersive virtual environment represents a space that is larger than the available space within which a user can travel by directly walking, it becomes necessary to consider alternative methods for traveling through that space. The traditional solution is to require the user to travel 'indirectly', using a device that changes his viewpoint in the environment without actually requiring him to move - for example, a joystick. However, other solutions involving variations on direct walking are also possible. In this paper, we present a new metaphor for natural, augmented direct locomotion through moderately large-scale immersive virtual environments (IVEs) presented via head mounted display systems, which we call seven league boots. The key characteristic of this method is that it involves determining a user's intended direction of travel and then augmenting only the component of his or her motion that is aligned with that direction. After reviewing previously proposed methods for enabling intuitive locomotion through large IVEs, we begin by describing the technical implementation details of our novel method, discussing the various alternative options that we explored and parameters that we varied in an attempt to attain optimal performance. We then present the results of a pilot observer experiment that we conducted in an attempt to obtain objective, qualitative insight into the relative strengths and weaknesses of our new method, in comparison to the three most commonly used alternative locomotion methods: flying, via use of a wand; normal walking, with a uniform gain applied to the output of the tracker; and normal walking without gain, but with the location and orientation of the larger virtual environment periodically adjusted relative to position of the participant in the real environment. In this study we found, among other things, that for travel down a long, straight virtual hallway, participants overwhelmingly preferred the seven league boots method to the other methods, overall.