Multi-phase wall warner system for real walking in virtual environments

Real walking is a means to explore virtual environments that are even larger than a physical space. Avoiding collisions with the physical walls necessitates a system to warn users. This paper describes the design and implementation of a multi-phase warning system as a solution to this safety necessity. The first phase is a velocity-based warning based on time-to-impact. The second phase is distance-based and designed as an emergency warning. Combinations of acoustic and visual feedback mechanisms were tested in a study with 13 participants. The quantitative measures show that the system keeps users safe, while allowing them to freely explore the virtual environment.