Based on input and feedback from firefighters, we built a futuristic pump panel simulator using consumer VR hardware, basic electronics components, and simple physical props. The simulator mixes the physical and the virtual together in order to demonstrate how passive haptics can be used to enhance the user experience. This prototype will be used to explore how VR might be used with future first-responder training.

Visually-induced motion sickness (VIMS), also known as cyber-sickness, is a major challenge for wide-spread Virtual Reality (VR) adoption. VIMS can be reduced in different ways, for example by using high-quality tracking systems and reducing the user's field of view. However, there are no universal solutions for all situations, and a wide variety of techniques are needed in order for developers to choose the most appropriate options depending on their needs. One way to reduce VIMS is through the use of rest frames-portions of the virtual environment that remain fixed in relation to the real world and do not move as the user virtually moves. We report the results of two multi-day within-subjects studies with 44 subjects who used virtual travel to navigate the environment. In the first study, we investigated the influence of static rest frames with fixed opacity on user comfort. For the second study, we present an enhanced version of rest frames that we call dynamic rest frames, where the opacity of the rest frame changes in response to visually perceived motion as users virtually traversed the virtual environment. Results show that a virtual environment with a static or dynamic rest frame allowed users to travel through more waypoints before stopping due to discomfort compared to a virtual environment without a rest frame. Further, a virtual environment with a static rest frame was also found to result in more real-time reported comfort than when there was no rest frame.

VR has the potential to provide experiences and deliver results that cannot be otherwise achieved. However, interacting with immersive applications is not always straightforward and it is not just about an interface for the user to reach their goals. It is also about users working in an intuitive manner that is a pleasurable experience and devoid of frustration. Although VR systems and applications are incredibly complex, it is up to designers to take on the challenge of having the VR application intuitively communicate to users how the virtual world and its tools work so that those users can achieve their goals in an elegant and comfortable manner.

This tutorial will provide an introduction to Unity (http://www.unity3D.com) and several VR components that are designed to work with Unity. These VR components can be used in isolation or pieced together to provide fully immersive VR experiences. Unity is a feature rich multi-platform game engine for the creation of interactive 3D content. It includes an intuitive interface while at the same time allowing low-level access for developers. Thousands of assets provided by other content creators can be reused to quickly develop immersive experiences. Because of its intuitive interface, well designed architecture, and ability to easily reuse assets, 3D software can be developed in a fraction of time compared to traditional development. Consumer-level virtual-reality hardware combined with Unity have recently empowered hobbyists, professionals, and academics to quickly create virtual reality applications. Because of Unity's widespread use and ease of use, several virtual reality companies now fully support Unity. During this tutorial, participants will learn how to quickly build virtual reality applications from some of the leaders of Unity virtual reality development. Attendees will gain an understanding of how to use multiple VR components with Unity and will have enough knowledge to start building VR applications using Unity by the end of the tutorial.

In order to better understand how scene motion is perceived in immersive virtual environments, we measured scene-motion thresholds under different conditions across three experiments. Thresholds were measured during quasi-sinusoidal head yaw, single left-to-right or right-to-left head yaw, different phases of head yaw, slow to fast head yaw, scene motion relative to head yaw, and two scene illumination levels. We found that across various conditions 1) thresholds are greater when the scene moves with head yaw (corresponding to gain < 1:0) than when the scene moves against head yaw (corresponding to gain > 1:0), and 2) thresholds increase as head motion increases.

In immersive virtual environments (IVEs), users can control their virtual viewpoint by moving their tracked head and walking through the real world. Usually, movements in the real world are mapped one-to-one to virtual camera motions. With redirection techniques, the virtual camera is manipulated by applying gains to user motion so that the virtual world moves differently than the real world. Thus, users can walk through large-scale IVEs while physically remaining in a reasonably small workspace. In psychophysical experiments with a two-alternative forced-choice task, we have quantified how much humans can unknowingly be redirected on physical paths that are different from the visually perceived paths. We tested 12 subjects in three different experiments: (E1) discrimination between virtual and physical rotations, (E2) discrimination between virtual and physical straightforward movements, and (E3) discrimination of path curvature. In experiment E1, subjects performed rotations with different gains, and then had to choose whether the visually perceived rotation was smaller or greater than the physical rotation. In experiment E2, subjects chose whether the physical walk was shorter or longer than the visually perceived scaled travel distance. In experiment E3, subjects estimate the path curvature when walking a curved path in the real world while the visual display shows a straight path in the virtual world. Our results show that users can be turned physically about 49 percent more or 20 percent less than the perceived virtual rotation, distances can be downscaled by 14 percent and upscaled by 26 percent, and users can be redirected on a circular arc with a radius greater than 22 m while they believe that they are walking straight.

To better understand motion perception in immersive virtual environments, we conducted a user study to quantify perception of scene motion as subjects yawed their heads. We measured psychometric functions of scene-velocity thresholds for different head motions and then extracted 75% thresholds, creating scene-velocity thresholds as functions of three measures of head motion: 1) Angular Range, 2) Peak Angular Velocity, 3) and Peak Angular Acceleration. We also measured scene-velocity thresholds for four phases of head motion: 1) the Start of the head turn, 2) the Center of the head turn, 3) the End of the head turn, 4) and All of the head turn. Scene-velocity thresholds increased as head motion increased for all tested conditions.

As users of head-tracked head-mounted display systems move their heads, latency causes unnatural scene motion. We 1) analyzed scene motion due to latency and head motion, 2) developed a mathematical model relating latency, head motion, scene motion, and perception thresholds, 3) developed procedures to determine perceptual thresholds of scene-velocity and latency without the need for a head-mounted display or a low-latency system, and 4), for six subjects under a specific set of conditions, we measured scene-velocity and latency thresholds, and compared the relationship between these thresholds. Resulting PSEs and JNDs of latency thresholds are in the same range of Ellis and Adelstein. The results are a step toward enabling scientists and engineers to determine latency requirements before building immersive virtual environments using head-mounted display systems.

Traveling through immersive virtual environments (IVEs) by means of real walking is an important activity to increase naturalness of VR-based interaction. However, the size of the virtual world often exceeds the size of the tracked space so that a straightforward implementation of omni-directional and unlimited walking is not possible. Redirected walking is one concept to solve this problem of walking in IVEs by inconspicuously guiding the user on a physical path that may differ from the path the user visually perceives. When the user approaches a virtual object she can be redirected to a real proxy object that is registered to the virtual counterpart and provides passive haptic feedback. In such passive haptic environments, any number of virtual objects can be mapped to proxy objects having similar haptic properties, e.g., size, shape and texture. The user can sense a virtual object by touching its real world counterpart. Redirecting a user to a registered proxy object makes it necessary to predict the user's intended position in the IVE. Based on this target position we determine a path through the physical space such that the user is guided to the registered proxy object. We present a taxonomy of possible redirection techniques that enable user guidance such that inconsistencies between visual and proprioceptive stimuli are imperceptible. We describe how a user's target in the virtual world can be predicted reliably and how a corresponding real-world path to the registered proxy object can be derived.

Redirected walking allows users to walk through large-scale immersive virtual environments (IVEs) while physically remaining in a reasonably small workspace by intentionally injecting scene motion into the IVE. In a constant stimuli experiment with a twoalternative-forced-choice task we have quantified how much humans can unknowingly be redirected on virtual paths which are different from the paths they actually walk. 18 subjects have been tested in four different experiments: (E1a) discrimination between virtual and physical rotation, (E1b) discrimination between two successive rotations, (E2) discrimination between virtual and physical translation, and discrimination of walking direction (E3a) without and (E3b) with start-up. In experiment E1a subjects performed rotations to which different gains have been applied, and then had to choose whether or not the visually perceived rotation was greater than the physical rotation. In experiment E1b subjects discriminated between two successive rotations where different gains have been applied to the physical rotation. In experiment E2 subjects chose if they thought that the physical walk was longer than the visually perceived scaled travel distance. In experiment E3a subjects walked a straight path in the IVE which was physically bent to the left or to the right, and they estimate the direction of the curvature. In experiment E3a the gain was applied immediately, whereas the gain was applied after a start-up of two meters in experiment E3b. Our results show that users can be turned physically about 68% more or 10 % less than the perceived virtual rotation, distances can be up- or down-scaled by 22%, and users can be redirected on an circular arc with a radius greater than 24 meters while they believe they are walking straight.

This paper describes a 2D videoconferencing system with eye gaze correction. Tracking the eyes and warping the eyes appropriately each frame appears to create natural eye contact between users. The geometry of the eyes as well as the displacement of the camera with the remote user's image determines the warp. We implement this system within software, not requiring any specialized hardware.