Towards Understanding the Impacts of Virtual Terrain on User Experiences in VR

Virtual Reality (VR) technologies have gained enormous traction due to the advancement of head-mounted displays (HMD). These wearable devices allow users to direct their gaze within simulated environments and open up many new applications including immersive education, the controlled treatment of phobias, and novel interfaces in drone piloting. VR technology is impeded by cybersickness, a collection of unwanted symptoms that affect a significant number of individuals. During a systematic review of existing cybersickness mitigation strategies, I implemented many approaches and made them available in an open-source software package. While cataloging these approaches I identified a research gap: a lack of studies examining the impacts of virtual terrain on cybersickness. Simulations often require users to navigate across virtual terrain that changes the user's level of elevation. I have dubbed this terrain "elevation-altering terrain" (EAT).I conducted a study with 38 participants comparing cybersickness levels across three terrain types: flat surface, terrain with regular bumps, and irregular terrain generated from Perlin noise. Results from this study indicated that users felt greater cybersickness while navigating EAT compared to flat surfaces. In a second study with 39 participants, I examined the impacts of EAT in the form of staircases on cybersickness, presence, and interactions with an embodied conversational agent (ECA). Results from this study indicated that EAT increased user cybersickness compared to flat terrain but may have also increased user presence. I then proposed a novel cybersickness reduction strategy called SmoothRide that operates by dampening a user's vertical motion as they move across EAT. In my third study with 43 participants, I compared SmoothRide against invisible surfaces that eliminate vertical motion and static field of view reduction. Results indicate FOV reduction and SmoothRide may be effective in mitigating cybersickness.