Walking outside the box: Estimation of detection thresholds for non-forward steps

Most virtual reality (VR) experiences are held in limited physical space; therefore, increasing the physical space's spatial efficiency is an essential task for the VR industry. Redirected walking maps a virtual path and a real path with unnoticeable distortion, enabling users to walk through a much bigger virtual space than physical space. To hide the distortion from the user, detection thresholds have been measured, entirely focusing on forward steps. However, it is not uncommon for the user to walk non-forward, that is, sideward and backward in VR. In addition to a forward step, adding options for a non-forward step can expand the VR locomotion in any direction. In this work, we measure the translation and curvature detection thresholds for non-forward steps. The results show similar translation detection thresholds with forward-step and wider detection thresholds for the curvature gain in both backward and sideward step experiments. Having sideward and backward steps in the redirected walking arsenal can add freedom to virtual world design and lead to efficient space usage.