Inducing Unintentional Positional Drift (UPD) in Virtual Reality via Physical Rotations and the Illusion of Leaning

In Virtual Reality (VR) users often turn their bodies during experiences. Virtual navigation techniques use body rotations and virtual forward translations to simulate movement. Despite being designed for stationary use, these techniques can cause Unintentional Positional Drift (UPD), impacting user safety and VR experiences. We carried out a human-participant study, approved by our university ethics board, involving 20 participants performing repetitive rotation tasks. Our study focused on intentionally inducing UPD via physical rotations by adding an offset to the VR camera’s roll angle, creating a visual illusion of "leaning" or "banking." Our results show that camera roll offsets induced UPD along participants initial left-right axis under specific conditions. Additionally, rotation magnitude and forward translation flow affected UPD, while no significant effects were found due to rotation direction.