Redirected Placement: Evaluating the Redirection of Passive Props during Reach-to-Place in Virtual Reality

Hand redirection is an effective technique that can provide users with haptic feedback in virtual reality (VR) when a disparity exists between virtual objects and their physical counterparts. Psychophysiological research has revealed the distinct motion profiles of different kinematic phases when people operate hand-object interaction. In this paper, we proposed the Redirected Placement (RP), which determines the new placement of a physical prop using a constrained optimization problem. The visual illusion is used during the "reach-to-place" kinematic phase in the proposed RP method rather than the "reach-to-grasp" phase in the typical Redirected Reach (RR) method. We conducted two experiments based on the proposed RP method. Our first experiment showed that detection thresholds are generally higher with the proposed method compared to the RR method. The second experiment evaluated the embodiment experience with hand redirection using RR-only, RP-only, and RR&RP methods. The results report an enhanced sense of embodiment with the combined use of both RR and RP techniques. Our study further indicates that a 1:1 combination ratio of RR&RP resulted in the closest subjective experience to the baseline.