Tapping-In-Place: Increasing the naturalness of immersive walking-in-place locomotion through novel gestural input

Walking-In-Place (WIP) techniques provide one possible solution to the problem emerging when an immersive virtual environment (IVE) offers a larger freedom of movement than the physical environment where the interaction is taking place. Such techniques are particularly useful when the spatial constraints are very prominent. However, many previous WIP techniques rely on the same gesture for input - a stepping gesture resembling the one performed when walking up a flight of stairs. It seems possible that this gesture may be perceived as more physically straining than real walking which may lead to a less natural walking experience. In this paper we present two novel forms of gestural input for WIP locomotion and describe a within subjects study comparing these to the traditional stepping gesture. The two gestures proposed are: a wiping gesture where the user alternately bends each knee, moving one lower leg backwards, and a tapping gesture where the user in turn lifts each heel without breaking contact with the ground. Visual feedback was delivered through a head-mounted display and auditory feedback was provided by means of a 24-channel surround sound system. The gestures were evaluated in terms of perceived naturalness, presence, and real world positional drift. The tapping gesture was significantly more natural than the wiping gesture and was experienced as significantly less strenuous than the other two techniques. Finally, the tapping gesture resulted in significantly less positional drift.