In redirected walking techniques, curvature gain and bending gain, which are referred to as curvature manipulation, are important redirection gains. The applied gains can differ when multiple paths are mapped, and sudden changes in gain may cause discomfort. This study proposes quadratic curvature manipulation (QCM) based on the habituation mechanism to effectively reduce discomfort. This method quadratically adjusts the path curvature, thereby reducing user's perception of curvature changes. Furthermore, we introduce the segmented curvature change (SCC) mode that combines QCM with linear curvature manipulation to facilitate more natural gain transitions, thereby reducing discomfort. Two experiments were conducted. Experiment 1 examined the relationship between QCM parameters and gains at which users felt discomfort. Experiment 2 further examined the effects of different curvature change modes on discomfort. The results indicate that using the SCC mode in curvature manipulations is more effective than other methods in reducing discomfort.

Virtual reality (VR), particularly through multi-user VR systems, enhances collaboration and immersion. However, multi-team VR systems (MTVR), which allow several teams to interact, either by cooperating or competing, are less studied. Drawing inspiration from concepts in game theory, specifically the positive-sum game (PSG) and zero-sum game (ZSG), this study investigated the impact of inter-team competition modes at the team level and haptic feedback at the individual level on team flow and individual flow for the first time. An experimental MTVR that supports inter-team competition in a two-person vs two-person pattern was implemented first. Then, a$2 \times 2$within-subject experiment was conducted to examine the effects of different inter-team competition modes (PSG/ZSG) and haptic feedback (on/off). The results based on 188 participants indicate that the PSG mode leads to significantly higher levels of collective ambition and improved team relationships compared to the ZSG mode. Furthermore, providing haptic feedback can significantly enhance awareness of shared and personal task goals, resulting in more cautious performance during teamwork.

Panoramic roaming with HMDs provides an immersive VR experience and the realism of user’s navigation in panoramic virtual environments (VEs) can be further enhanced by real-walking locomotion technology. However, the mismatched viewpoint height & fluctuation with the user’s visual senses may lead to perceptual conflicts during real-walking interaction. We conducted a series of user studies to investigate how viewpoint height & fluctuation affect the walking perception of users by real-walking interaction to navigate panoramic VEs and constructed a virtual camera motion model of viewpoint fluctuation and eyetracking compensation for walking behavior in panoramic virtual roaming. It was found that mismatched viewpoint fluctuation triggered generalized discomfort in participants and that participants preferred virtual viewpoint heights below eye level when roaming in panoramic VEs by real-walking. Considering these findings, we proposed viewpoint adaptive adjustment method based on visual manipulation and conducted a preliminary evaluation, which showed that the proposed method can effectively mitigate the conflict between the visual system and other sensory systems. It made that panoramic VEs constructed at a certain fixed height are rendered universal for users with different eyelevel heights and viewpoint fluctuation is matched to the undulation of their center of gravity during real-walking interaction.

Abstract Current VR/AR system development studios lack a toolkit that can automatically generate hierarchical tile menu layouts and menu prototypes for VR/AR devices without the need for user programming. This paper proposes a solution in the form of a toolkit that automatically generates a hierarchy tile menu layout using a modified circular treemap algorithm. Users can interactively arrange and resize tiles to create various layouts according to their preferences or needs, utilizing a circle packer method. The toolkit further automatically generates a VR/AR menu prototype based on the resulting layout. Notably, reprogramming is not necessary each time the hierarchy is modified or the menu layout is redesigned. The user test results demonstrate that the proposed toolkit simplifies the creation of hierarchical tile menu layouts, enhances user efficiency in the design process, and enables users to flexibly create hierarchical tile menu prototypes according to their design ideas.

Summary Reaction time, the ability to detect, process and respond to stimuli, is one of the fundamental factors in human computer interaction, and is a key cognitive skill in clinical and healthy populations. Good reaction time allows us to respond to stimuli and situations with agility and efficiency. How to train and improve a person's reaction time has become an important research question. In this paper, we present a new training genre which combines the user‐centered personalized training objects generation with precise tracking of foot interaction.Virtual objects are created with respect to the user's features and historical training effectiveness, and are in motion. A foot tracking algorithm based on three‐Gaussian model is designed to support interaction with stepping on moving virtual objects. We present the design and implementation of the system, as well as user studies. Findings illustrate that the reaction time performances are significantly improved following of seven days of training based on foot interaction.

Online fitness training, with its affordability and flexibility, offers a convenient way for individuals to engage in regular workouts that promote physical and mental health. Yet, learning fitness motions in this way presents various challenges and may not always be as effective as in-person training. To address the practical demands of motion learning, we conducted a systematic survey and accordingly proposed a four-stage self-learning genre that integrates immersive virtual reality (VR) environments with motion skill learning theories, strategies, and expert experience. Herein, we merged progressive structures and multi-level visual cues to enhance instruction, and proposed a fine-grained motion analysis method to provide adaptive correction feedback during training. Utilizing a Taichi training platform with the genre embedded, we systematically validated the effectiveness of the genre, and examined the potential impact of VR content presentation form on motion learning among different age groups, as well as their preferences and focus on VR fitness training genre design. Results from the quantitative analysis, qualitative evaluation, and case study showed that the 360° video-based VR content brought more positive motion learning performance and user experiences than the fully-simulated VR used in many previous studies. The proposed genre demonstrated outstandingly performance, experience, and usability, with each stage and design playing an effective role. Moreover, we offer several design considerations for VR fitness systems targeting diverse age groups, providing beneficial insights for VR development in the sports and health-related fields.

Along with the development of network and virtual reality (VR), VR-based telerobotic systems have been widely applied in many fields, especially in hazardous or uncertain environments. But the existing navigation methods of remote robot are implemented by operators using keyboard, mouse joystick, or walking-in-place devices in the VR environments that is telepresence of remote environments. In this paper, we propose a new navigation method for VR-based telerobotic system via operators' real walking in a limited physical space, wherein the motion of a remote robot is synchronized with that of an operator who is actually walking in a limited physical space while naturally interacting (head and body interaction) with the robot and experiencing the remote environment with the help of VR video real-timely captured by the robot. This makes the operators have better sense of presence at the remote sites than the existing methods. We design and implement a system based on this technology, and the test shows that it can make the robot flexible to be navigated in remote complex and dynamic environments.

This paper presents a mixed reality storytelling system, which takes handicrafts as tangible interaction tools. Via the system, users can learn handicraft and then use the handicraft pieces to design, create and tell stories with HoloLens iteratively. In order to overcome the limitations of HoloLens gesture interaction, the system uses hand tracking with Kinect to implement a touch-like effect on the desktop. User study shows that our system has good usability, and it is welcomed by users. In addition, it can stimulate users interest in handicraft and storytelling, and even promote parent-child interaction effectively.

This paper presents a toolkit called Rotbav for easily constructing mixed reality (MR) apps that can be experienced in real time in large indoor physical space via HoloLens. It resolves the problem that existing MR devices, e.g. HoloLens, are unable to scan and model an entire large scene with several rooms at once. We introduce a custom data structure called VorPa, based on the Voronoi diagram, to implement path editing, accelerated rendering and location effectively. Our experiments and applications show that the toolkit is convenient and easy to use for constructing MR apps targeting large indoor physical spaces, in which users can roam in real time.

Many studies conducted in non-virtual activities have shown that flow significantly influences performance, yet studies in virtual activities often reveal only a weak association. This paper begins by building a theoretical explanatory model, and then conducts 3 empirical studies to explore this question. Study 1 exams the mechanism of weak association in two virtual activities. Study 2 tests the effectiveness of a potential approach to strengthen this association. In Study 3 we applied our proposed model and design approach to optimize a VR tennis game. Results show that the influence of flow on performance was not significant in those virtual activities where the primary task and the operation of interactive artifacts were less congruent such that the artifacts can lead to flow experience that is independently of the primary task. Our research offers a theoretical and empirical basis on how to optimize virtual environment design and maximize positive effect of the flow experience.

Stereoscopic display is a standard display mode for virtual reality environments. Typical 3D projection provides only a single stereoscopic video stream; thus co-located users cannot correctly perceive the virtual scene based on their own position and view. Several works devoted to developing multi-user stereoscopic display, but the number of users is very limited or the technical implementation is complicated. In this paper we put forward two flexible and simple projection-based multi-user stereoscopic display systems. The first one, named TPA, is based on a triple-projector array and provides a 120Hz active stereo for three users. Two TPAs can be combined to form a six-user system. The second one, named DPA, is a dual-projector and easy-implemented system providing individual stereoscopic video stream for two to six users. Finally, a co-located multi-user virtual fireman simulation training system and a virtual tennis simulation system were created to verify the effectiveness of our systems.

With the fast development of virtual reality games, one of the key research questions is how players may express their creativity and participate in the process of game design. In this paper, we present a new game genre which combines user-controlled game design in physical space with game play in virtual space on a mobile device. The new system supports authoring by anyone, creating virtual reality games that can be easily modified or developed for physical space, and be used anywhere by novice end-users without any knowledge of tracking technology. We present the design and implementation of the system, as well as a user experiment. Findings illustrate that the proposed system promotes participation and provides a richer, more interactive and engaging experience.