The effects of head-mounted display mechanics on distance judgments in virtual environments

In virtual environments that use head-mounted displays (HMD), distance judgments to targets on the ground are compressed, at least when indicated through visually-directed walking tasks. The same tasks performed in the real world yield veridical results over distances ranging from 2m to 25m. This paper describes experiments aimed at determining if mechanical aspects of HMDs such as mass and moments of inertia are responsible for the apparent distortion of distance. Our results indicate that the mechanical aspects of HMDs cannot explain the full magnitude of distance underestimation seen in HMD-based virtual environments, though they may account for a portion of the effect.