Gaze Teleportation in Virtual Reality

UPDATED—June 7, 2017. This paper reports preliminary investigations into gaze teleportation, a locomotion interaction inside virtual reality in which the user can push a button and teleport to the point at which they are looking. The results could help future application creators design intuitive locomotion interfaces to allow users to more easily scale virtual worlds larger than their play space. In a study consisting of 12 participants, gaze teleportation was compared to the conventional hand-tracked controller. Participants played a portion of Valve’s The Lab with an HTC Vive and a Tobii Eyetracker; half of the participants completed the set tasks with gaze teleportation, and the other half used hand-tracking. Using Likert questions, they then rated their experiences in terms of enjoyment, frustration, effort, distance, occlusion, immersion, and motion sickness. After answering the questions, the participants got to try both methods and were interviewed on their preferences and opinions. Our results suggest that gaze teleportation is an enjoyable, fast, intuitive, and natural locomotion method that performs similarly to hand-tracked teleportation but is preferred by users when they are given a choice. We conclude that gaze teleportation is a good fit for applications in which users are expected to locomote in their direction of focus without too many distractions. INTRODUCTION Commercial virtual reality (VR) headsets such as the HTC VIVE1 and Oculus Rift2, which are currently entering the consumer market, are capable of unprecedented visual fidelity and immersion. The interaction conventions for these virtual environments is still uncertain, and there is much room for experimentation. New VR technology brings new challenges in user interaction, especially regarding locomotion. Locomotion is one of the big fundamental problems that VR application creators must solve, with play spaces smaller than the virtual world and traditional input devices such as the keyboard, mouse, or joystick, that can induce motion sickness. VR locomotion is an old question. The proposed solutions are many, all providing different degrees of freedom, sense of control, efficiency, and motion sickness. The one technique that stands out in the current applications is teleportation, which is quickly becoming one of the most prominent means of VR interaction as it induces minimal motion sickness and offers the user an efficient way to move about virtual spaces that are larger than the tracked physical area. Teleportation starts with detecting the target location. Many current VR applications use hand controllers for this interaction, but research by Gandrud and Interrante [7] suggests that pointing with the controller could be an unnecessary step. They concluded that gaze is a good predictor for the 1https://www.vive.com/ 2https://www.oculus.com/rift/ direction toward which users intend to move as it represents an action that users are already doing. Modern state-of-theart eye trackers can detect gaze direction with an accuracy of less than one degree and fit well into new commercial headsets. We have suggested replacing hand controllers with gaze to direct teleportation using raycasting to identify exactly where the user is looking within the virtual world and then providing the means for the user to move to that location. This study has investigated this new type of teleportation method and compared it to the conventional hand tracking method. An example of the two approaches can be seen in Figure 9. RESEARCH QUESTION Is eye tracking a suitable input method for teleportation in virtual reality? As suitability is evaluated in relation to other teleportation methods, this study compared gaze interactions to the current conventional method of using motion-tracked hand controllers. RELATED RESEARCH VR Locomotion, interaction and eye tracking integration is nothing new. Locomotion is one of the most fundamental problems for VR. Early research into VR locomotion included omnidirectional treadmills (see Figure 1), which have seen an upswing in consumer markets as of late3456, but have recently received limited attention. They have been shown to be slippery, hard to enter and exit, limit freedom of movement, and can cause some motion sickness [6]. Another medium fidelity locomotion technique (as opposed to high fidelity natural walking interfaces and low fidelity joysticks) is hamster balls such as Virtusphere7 (see Figure 2). They have been shown to perform worse than both high and low fidelity interfaces as the expectations of the interface are that it will be similar to natural walking. The hamster ball makes turning and termination difficult, which limits freedom of movement and provides no real improvement in eliminating motion sickness. [12] A more common method for locomotion on recent mobile platforms such as the Samsung Gear VR8 is to navigate in the direction of the head. This technique is effected by Midas-Touch as shall subsequently be discussed, but activation methods vary between button activation and walkin-place with walk-in-place being the most common [18]. 3http://www.virtuix.com/ 4http://www.vuetechnologie.com/product/ vue-vr-treadmill/ 5http://www.katvr.com/English.html 6http://cyberith.com/product/ 7http://www.virtusphere.com/ 8http://www.samsung.com/global/galaxy/gear-vr/