Tapping with a Handheld Stick in VR: Redirection Detection Thresholds for Passive Haptic Feedback

This paper investigates providing grounded passive haptic feedback to a user of a VR application through a handheld stick with which the user taps virtual objects. Such an investigation benefits VR applications beyond those where the stick interaction is actually an integral part of the narrative. Providing passive haptic feedback through a handheld stick as opposed to directly through the user’s hand has the potential for more believable and more frequent feedback opportunities. The stick is likely to dull the user’s haptics perception and proprioception, potentially avoiding a haptics perception uncanny valley and increasing the redirection detection thresholds. Two haptics redirection methods are proposed: the DriftingHand method, which alters the position of the user’s virtual hand, and the Vari-Stick method, which alters the length of the virtual stick. Detection thresholds were measured in a user study (N = 60) by testing the two methods for a range of offsets between the virtual and the real object, for multiple stick lengths, and multiple distances from the user to the real object. Overall, the study reveals that VariStick and DriftingHand provide an undetectable range of offsets of [-20cm, +13cm] and [-11cm, +11cm], respectively.