Comparing VE locomotion interfaces

Abstract

To compare and evaluate locomotion interfaces for users who are (virtually) moving on foot in VEs, we performed a study to characterize task behavior and task performance with different visual and locomotion interfaces. In both a computer-generated environment and a corresponding real environment, study participants walked to targets on walls and stopped as close to them as they could without making contact. In each of five experimental conditions participants used a combination of one of three locomotion interfaces (really walking, walking-in-place, and joystick flying), and one of three visual conditions (head-mounted display, unrestricted natural vision, or field-of-view-restricted natural vision). We identified metrics and collected data that captured task performance and the underlying kinematics of the task. Our results show: 1) Over 95% of the variance in simple motion paths is captured in three critical values: peak velocity; when, in the course of a motion, the peak velocity occurs; and peak deceleration. 2) Correlations of those critical value data for the conditions taken pairwise suggest a coarse ordering of locomotion interfaces by "naturalness." 3) Task performance varies with interface condition, but correlations of that value for conditions taken pairwise do not cluster by naturalness. 4) The perceptual variable, τ (also known as the time-to-contact) calculated at the point of peak deceleration has higher correlation with task performance than τ calculated at peak velocity.