An evaluation of strategies for two-user redirected walking in shared physical spaces

As the focus of virtual reality technology is shifting from singleperson experiences to multi-user interactions, it becomes increasingly important to accommodate multiple co-located users within a shared real-world space. For locomotion and navigation, the introduction of multiple users moving both virtually and physically creates additional challenges related to potential user-on-user collisions. In this work, we focus on defining the extent of these challenges, in order to apply redirected walking to two users immersed in virtual reality experiences within a shared physical tracked space. Using a computer simulation framework, we explore the costs and benefits of splitting available physical space between users versus attempting to algorithmically prevent user-to-user collisions. We also explore fundamental components of collision prevention such as steering the users away from each other, forced stopping, and user re-orientation. Each component was analyzed for the number of potential disruptions to the flow of the virtual experience. We also develop a novel collision prevention algorithm that reduces overall interruptions by 17.6% and collision prevention events by 58.3%. Our results show that sharing space using our collision prevention method is superior to subdividing the tracked space.