Target selection-based teleportation is one of the most prevalent locomotion techniques in immersive virtual environments, mitigating visual motion sickness and overcoming physical space constraints. However, the conventional Point & Teleport method, widely implemented in commercial VR systems, restricts navigation to planar surfaces, limiting exploration of mid-air positions essential for tasks such as obtaining elevated viewpoints or bypassing obstacles. Mid-air teleportation extends the Point & Teleport metaphor to support free navigation in three-dimensional space, yet the influence of visual feedback on its performance and usability remains underexplored. This paper investigates six different implementations of visual feedback techniques during target specification in mid-air teleportation. We evaluated these techniques through a user study with 56 participants. The results reveal trade-offs between the downward-facing camera, which achieves the highest accuracy, and other visual feedback techniques that rely on occlusion cues, such as the spherical pointer, the spherical boundary, the ground reference cylinder, and the avatar, which result in lower task completion time. We propose initial design guidelines for target selection-based mid-air teleportation based on our findings.

Cross Reality (CR) is a new emerging field based on the current developments in Mixed Reality hardware, especially supported by the broad market penetration of video-based see-through Head-Mounted Displays. It refers to applications that span across different stages (real, Augmented Reality, Augmented Virtuality, Virtual Reality) of the reality-virtuality continuum, where users are interconnected between different stages and/or are able to transition between these stages. This publication follows the concept of other grand challenges publications and reflects the discussion of various researchers invested in CR. After an initial discussion at the 1stJoint Workshop on Cross Reality at IEEE ISMAR 2023, six topic groups have been identified, leading to 22 challenges, which were discussed in groups over the period of multiple months. The discussion of these challenges should act as a road map for future research in the area of CR.

Cybersickness remains a major barrier to the widespread adoption of virtual reality (VR) technologies, motivating researchers to investigate its causes and mitigation strategies through comparative human-subjects studies. These experiments may employ either within- or between-subjects designs. Although within-subjects designs require fewer participants and potentially offer higher statistical power, researchers need to wash out carryover effects of cybersickness symptoms before each session to avoid confounding the results. Prior studies have employed washout periods of varying lengths; some required testing conditions on different days, while others allowed only short breaks of less than 15 minutes. Although shorter washout periods are more convenient for experimenters, their impact on study outcomes has not been systematically investigated. In this work, we conducted a meta-analysis to evaluate the effects of study design and washout period length on cybersickness self-reports measured with the Simulator Sickness Questionnaire (SSQ). We found that short washout periods reduce statistical power compared to long washout periods or between-subjects designs. Based on these findings, we provide guidelines to help researchers design more reliable cybersickness studies and improve the generalizability of their results.

Traditional target-selection-based teleportation depends on the intersection of a (curved) ray with the scene's geometry, which limits navigation to points on the ground, restricting users' navigational freedom. While previous techniques exist that permit mid-air target selection, they are not optimal for transitioning between air and ground navigation, leading to inaccurate or lengthy interaction sequences. In this paper, we introduce SATOR, a new 3D teleportation technique designed to enable efficient and accurate navigation to both ground and mid-air targets by combining and enhancing previous approaches. Informed by the literature, we implemented four different parametrizations of our technique and compared them to a previously published technique that also enables both ground and mid-air target selection. Our user study with 30 participants indicates that SATOR is more efficient, accurate, and easier to use than the baseline. As a result, SATOR effectively helps users get an overview of the environment, observe features at different heights, or maneuver quickly around larger obstacles.

Target-selection-based teleportation is one of the most widely used and researched travel techniques in immersive virtual environments, requiring the user to specify a target location with a selection ray before being transported there. This work explores the influence of the maximum reach of the parabolic selection ray, modeled by different emission velocities of the projectile motion equation, and compares the resulting teleportation performance to a straight ray as the baseline. In a user study with 60 participants, we asked participants to teleport as far as possible while still remaining within accuracy constraints to understand how the theoretical implications of the projectile motion equation apply to a realistic VR use case. We found that a projectile emission velocity of $14 \frac{m}{s}$14ms (resulting in a maximal reach of $\text{21.52 m}$21.52m) offered the best trade-off between selection distance and accuracy, with an inferior performance of the straight ray. Our results demonstrate the necessity to carefully set and report the projectile emission velocity in future work, as it was shown to directly influence user-selected distance, selection errors, and controller height during selection.

In this work, we explore the integration of Orientation Selection into Steering interfaces, aiming to preserve the seamless sensation of real-world movement while mitigating the risk of inducing cybersickness. Our implementation encounters conflicts in standard input mappings, prompting us to adopt bimanual interaction as a solution. Recognizing the complexity of interaction that may arise from this step, we also develop unimanual alternatives, e.g., utilizing a Human-Joystick, commonly referred to as a Leaning interface. The outcomes of an empirical study centered around a primed search task yield unexpected findings. We observed a sample of users spanning multiple levels of gaming experience and a balanced gender distribution exhibit no significant difficulties with the bimanual, asymmetric interfaces. Remarkably, the performance of Orientation Selection is, as in prior work, at least on par with Snap Rotation. Moreover, through a subsequent exploratory analysis, we uncover indications that Pointing-Directed Steering outperforms embodied interfaces in usability and task load in the given setting.

Traveling distances in the real world inherently involves the passage of time, as reaching a desired location is a continuous process. This temporal component, for instance, influences how distances are perceived and estimated. However, in virtual environments, this relationship is often altered or entirely absent. This can make locomotion faster, as is the case with point-and-click teleportation, but depending on the application, it may diminish the user experience or negatively affect distance perception. Instantaneous movement is often chosen due to its lack of negative effects on cybersickness rather than its efficiency. In this research, we explore methods to incorporate temporal elements into different stages of point-and-click teleportation. We investigate how these adjustments influence participants' perception of distance. Our findings show a reduction in distance underestimation when using a time-delayed teleportation method, confirming that temporal factors can impact distance perception in virtual environments.

Augmented Virtuality integrates physical content into virtual environments, but the occlusion of physical by virtual content is a challenge. This unwanted occlusion may disrupt user interactions with physical devices and compromise safety and usability. This paper investigates two resolution strategies to address this issue: Redirected Walking, which subtly adjusts the user’s movement to maintain physical-virtual alignment, and Automatic Teleport Rotation, which realigns the virtual environment during travel. A user study set in a virtual forest demonstrates that both methods effectively reduce occlusion. While in our testbed, Automatic Teleport Rotation achieves higher occlusion resolution, it is suspected to increase cybersickness compared to the less intrusive Redirected Walking approach.

Collaborative work in social virtual reality often requires an interplay of loosely coupled collaboration from different virtual locations and tightly coupled face-to-face collaboration. Without appropriate system mediation, however, transitioning between these phases requires high navigation and coordination efforts. In this paper, we present an interaction system that allows collaborators in virtual reality to seamlessly switch between different collaboration models known from related work. To this end, we present collaborators with functionalities that let them work on individual sub-tasks in different virtual locations, consult each other using asymmetric interaction patterns while keeping their current location, and temporarily or permanently join each other for face-to-face interaction. We evaluated our methods in a user study with 32 participants working in teams of two. Our quantitative results indicate that delegating the target selection process for a long-distance teleport significantly improves placement accuracy and decreases task load within the team. Our qualitative user feedback shows that our system can be applied to support flexible collaboration. In addition, the proposed interaction sequence received positive evaluations from teams with varying VR experiences.

The paper investigates how users want to transfer 3D virtual objects between a standard desktop monitor and an augmented reality head-mounted display setup during a Cross Reality session. An elicitation study with 20 participants was conducted to gather their preferred interactions and input modalities to select 3D virtual objects and trigger the transition. Participants were allowed to propose interactions belonging to various input modalities or a combination of interactions that utilize multiple input modalities. We labeled the observed data and analyzed the resulting 1200 input observations to derive a set of recommended interactions. We found that mid-air hand gestures Drag, Tap, and Grab were the most commonly proposed interactions and should be considered as the primary interaction for CR virtual objects transition assisted with other interactions and input modalities as the supplementary base on different user scenarios.

The user study presented in this paper explores the effects that being immersed in different virtual scenes has on a user’s avatar-design behavior. For this purpose, we have developed a character creation tool that lets users configure their appearance in Virtual Reality. This tool has then been employed in a user study involving 33 participants, who were asked to configure a virtual avatar in a beach and a hospital environment. Our results show that the environment that participants were immersed in influenced their design behavior, with the beach environment leading to a more extensive use of accessories than the hospital scene. Against our expectations, most participants stated to have had little intention to represent either their real or ideal selves, instead opting to explore different characters that they found funny, likable, or interesting. In addition, we found indications for a possible connection between the participants’ feelings of presence and how they incorporate features of themselves into their avatar designs.

This paper presents a VR-based serious game. The game aims to raise awareness about ocean pollution by immersing players in a virtual underwater world where they collect trash to prevent coral bleaching and save marine life. Despite their efforts, players inevitably face game over, highlighting the futility of merely collecting trash and underscoring the need to prevent waste from entering oceans. The game uses various diegetic feedback mechanisms and enhanced user presence features to deepen emotional engagement and promote pro-environmental behavior.

VRoot is an immersive extended reality reconstruction tool for root system architectures from 3D volumetric scans of soil columns. We have conducted a laboratory user study to assess the performance of new users with our software in comparison to established software. We utilize a plant model to derive a synthetic root architecture, providing a baseline for reconstruction. This demo showcases the processes and techniques contributing to exact and efficient manual root architecture reconstruction in Virtual Reality. The extraction task typically is the sparse graph-structure extraction from a 3D magnetic-resonance imaging (MRI) data set. We visualize the RSA directly within the MRI and offer selection-set-based methods of adapting and augmenting the root architecture. This application is in productive use at our partner institute, where it is used to analyze complex root images.

Virtual Reality presents a promising tool for knowledge transfer, allowing users to learn in different environments and with the help of three-dimensional visualizations. At the same time, having to learn new ways of interacting with their environment can present a significant hurdle for novice users. When users enter a virtual space to receive knowledge from a more experienced person, the question arises as to whether they benefit from learning VR-specific interaction techniques instead of letting the expert take over some or all interactions. Based on related work about expert-novice interaction in virtual spaces, this paper presents a user study comparing three different distributions of interaction responsibilities between participants and an expert user. The Role-Based interaction mode gives the expert the full interaction responsibility. The Shared interaction mode gives both users the same interaction capabilities, allowing them to share the responsibility of interacting with the virtual space. Finally, the Parallel interaction mode gives participants full interaction responsibility, while the expert can provide guidance through oral communication and visual demonstration. Our results indicate that assuming interaction responsibility led to higher task loads but also increased the participant’s engagement and feeling of presence. For most participants, sharing interaction responsibilities with the expert represented the best trade-off between engagement and challenge. While we did not measure a significant increase in learning success, participant comments indicated that they also paid more attention to details when assuming more interaction responsibility.

This paper introduces ChronoShore, an immersive virtual reality (VR) experience designed to explore diegetic time manipulation mechanics within a semi-realistic coastal environment. Traditional 2D video scrubbing methods fall short in immersive settings, particularly for understanding time-bound processes such as simulations of geology or biology. ChronoShore addresses this by allowing users to interact with celestial bodies to dynamically control and experience the passage of time, currently showcasing different weather events and atmospheric phenomena.

Fade-to-black animations are a commonly used technique to visualize transitions during teleportation. However, their duration varies across different implementations and has not been extensively researched. This abstract details a study design to understand how the level of environmental detail affects the preferred duration of fade-to-black animations. We propose a within-subject study, comparing participants’ preferred duration across three virtual environments with varying levels of detail. We discuss improvements to the task design of an existing study. Other than the level of environmental detail, we motivate research into the effects of different tasks (i.e. hurried or calm) on the preferred duration.

In this abstract, we discuss the demand for replication and extension efforts related to two seminal studies focused on virtual reality (VR) locomotion interfaces, initially centered around a VR implementation of the Visual Cliff, often referred to as Virtual Pit. The original experiments by Slater et al. (1995) and Usoh et al. (1999) compared different locomotion methods, including Real Walking, Walking-in-Place, and Flying/Steering, with a focus on presence and ease of use. We discuss the importance of these studies for the field, motivate replication efforts focused on these studies, discuss potential confounding factors, and present considerations for a concerted effort to reproduce the findings with state-of-the-art VR systems and measures, extensions to locomotion methods like Teleportation, and means to support future replications and extensions.

Cybersickness poses a significant barrier to the widespread adoption of VR applications, particularly when virtual movement occurs without corresponding physical movement. While current strategies to mitigate cybersickness exist, none are entirely effective, especially if virtual movement is essential. Further research is needed, and this requires controlled induction of cybersickness in empirical studies. In this demo, we introduce Cybersicker, a simulator designed to bridge the gap between high-intensity, proprietary simulators and less engaging alternatives. The simulator provides controlled translational and rotational vection while encouraging user participation.

Virtual travel in Virtual Reality experiences is common, offering users the ability to explore expansive virtual spaces. Various interfaces exist for virtual travel, with speed playing a crucial role in user experience and spatial awareness. Teleportation-based interfaces provide instantaneous transitions, whereas continuous and semi-continuous methods vary in speed and control. Prior research by Bowman et al. highlighted the impact of travel speed on spatial awareness demonstrating that instantaneous travel can lead to user disorientation. However, additional cues, such as visual target selection, can aid in reorientation. This study replicates and extends Bowman’s experiment, investigating the influence of travel speed and visual target cues on spatial orientation.

The inquiry into the impact of diverse transitions between cross-reality environments on user experience remains a compelling research endeavor. Existing work often offers fragmented perspectives on various techniques or confines itself to a singular segment of the reality-virtuality spectrum, be it virtual reality or augmented reality. This study embarks on bridging this knowledge gap by systematically assessing the effects of six prevalent transitions while users remain immersed in tasks spanning both virtual and physical domains. In particular, we investigate the effect of different transitions while the user is continuously engaged in a demanding task instead of purely focusing on a given transition. As a preliminary step, we evaluate these six transitions within the realm of pure virtual reality to establish a baseline. Our findings reveal a clear preference among participants for brief and efficient transitions in a task-driven experience, instead of transitions that prioritize interactivity and continuity. Subsequently, we extend our investigation into a cross-reality context, encompassing transitions between virtual and physical environments. Once again, our results underscore the prevailing preference for concise and effective transitions. Furthermore, our research offers intriguing insights about the potential mitigation of visual incoherence between virtual and augmented reality environments by utilizing different transitions.

The ability to reproduce previously published research findings is an important cornerstone of the scientific knowledge acquisition process. However, the exact details required to reproduce empirical experiments vary depending on the discipline. In this paper, we summarize key replication challenges as well as their specific consequences for VR locomotion research. We then present the results of a literature review on artificial locomotion techniques, in which we analyzed 61 papers published in the last five years with respect to their report of essential details required for reproduction. Our results indicate several issues in terms of the description of the experimental setup, the scientific rigor of the research process, and the generalizability of results, which altogether points towards a potential replication crisis in VR locomotion research. As a countermeasure, we provide guidelines to assist researchers with reporting future artificial locomotion experiments in a reproducible form.

Continuous locomotion in VR provides uninterrupted optical flow, which mimics real-world locomotion and supports path integration . However, optical flow limits the maximum speed and acceleration that can be effectively used without inducing cybersickness. In contrast, teleportation provides neither optical flow nor acceleration cues, and users can jump to any length without increasing cybersickness. However, teleportation cannot support continuous spatial updating and can increase disorientation. Thus, we designed 'HyperJump' in an attempt to merge benefits from continuous locomotion and teleportation. HyperJump adds iterative jumps every half a second on top of the continuous movement and was hypothesized to facilitate faster travel without compromising spatial awareness/orientation. In a user study, Participants travelled around a naturalistic virtual city with and without HyperJump (equivalent maximum speed). They followed waypoints to new landmarks, stopped near them and pointed back to all previously visited landmarks in random order. HyperJump was added to two continuous locomotion interfaces (controller- and leaning-based). Participants had better spatial awareness/orientation with leaning-based interfaces compared to controller-based (assessed via rapid pointing). With HyperJump, participants travelled significantly faster, while staying on the desired course without impairing their spatial knowledge. This provides evidence that optical flow can be effectively limited such that it facilitates faster travel without compromising spatial orientation. In future design iterations, we plan to utilize audio-visual effects to support jumping metaphors that help users better anticipate and interpret jumps, and use much larger virtual environments requiring faster speeds, where cybersickness will become increasingly prevalent and thus teleporting will become more important.

Embodied locomotion, especially leaning, has one major problem. Effectively the regular functionality of the utilized body parts is overwritten. Thus, in this work, we propose 6 different status control methods that seamlessly switch off (brake) a seated leaning locomotion interface. Different input modalities, such as a physical button, voice, and gestures/metaphors, are used and evaluated against a baseline condition and a leaning interface with a bilateral transfer function. In a user study, participants were encouraged, but not forced to use these interfaces. They did, and the most diegetic interface, a hover-board metaphor, was the most preferred. However, the overall results are more heterogeneous and the interfaces vary in their suitability for different applications/scenarios. Therefore, we summarized the results in a guideline.

Continuous virtual rotation is likely one of the biggest contributors to cybersickness, while simultaneously being necessary for many VR scenarios where the user, for instance, is sitting in a bus, at an office desk, or on a couch and therefore, limited in physical body rotation. A possible solution is discrete virtual rotation, such as already broadly accepted in translational movements (teleportation). In this work, we want to help increase the knowledge about discrete virtual rotations. We classify existing work and systematically investigate the two dimensionstarget(rotation)acquisition(selectionvs. directional)and body-based (yes vs. no) regarding their impact on the performance in a naive and a primed rotational search task, spatial orientation, and usability. We do find the novel virtual rotation selection most successful in both search tasks and no difference in the factor bodybased on spatial orientation.

Virtual Reality is increasingly used for safe evaluation and validation of autonomous vehicles by automotive engineers. However, the design and creation of virtual testing environments is a cumbersome process. Engineers are bound to utilize desktop-based authoring tools, and a high level of expertise is necessary. By performing scene authoring entirely inside VR, faster design iterations become possible. To this end, we propose a VR authoring environment that enables engineers to design road networks and traffic scenarios for automated vehicle testing based on free-hand interaction. We present a 3D interaction technique for the efficient placement and selection of virtual objects that is employed on a 2D panel. We conducted a comparative user study in which our interaction technique outperformed existing approaches regarding precision and task completion time. Furthermore, we demonstrate the effectiveness of the system by a qualitative user study with domain experts.

Leaning (the upper body) has several times been shown to be a suitable virtual travel technique when being seated; in both, flying as well as ground-based scenarios. The direction of the steering method most commonly used is gaze/head-directed. However, this does not allow to inspect the environment independently from the direction of movement. The change to torso-directed steering allows for the latter and additionally does not take anything from the natural character of the leaning metaphor. We empirically investigated the impact of this freedom in a ground-based scenario and complemented the conditions with a virtual body-directed method and then crossed all with device-based control conditions. In the conducted study (n = 25), we found the torso-directed methods objectively performed the best (traveled distance, completion time & number of collisions), and found torso-directed leaning subjectively rated the most usable one.

In this work, we evaluate the impact of passive haptic feedback on touch-based menus, given the constraints and possibilities of a seated, desk-based scenario in VR. Therefore, we compare a menu that once is placed on the surface of a desk and once mid-air on a surface in front of the user. The study design is completed by two conditions without passive haptic feedback. In the conducted user study (n=33), we found effects of passive haptics (present vs-non-present) and menu alignment (desk vs. mid-air) on the task performance and subjective look & feel. However, the race between the conditions was close. An overall winner was the mid-air menu with passive haptic feedback, which however raises hardware requirements.

In this work, we evaluate the feasibility of an office desk substitution in the context of a visual data analysis task involving travel. We measure the impact on cybersickness as well as the general task performance and presence. In the conducted user study (n=52), surprisingly, and partially in contradiction to existing work, we found no significant differences for those core measures between the control condition without a virtual table and the condition containing a virtual table.

The ongoing migration of HMDs to the consumer market also allows the integration of immersive environments into analysis workflows that are often bound to an (office) desk. However, a critical factor when considering VR solutions for professional applications is the prevention of cybersickness. In the given scenario the user is usually seated and the surrounding real world environment is very dominant, where the most dominant part is maybe the desk itself. Including this desk in the virtual environment could serve as a resting frame and thus reduce cybersickness next to a lot of further possibilities. In this work, we evaluate the feasibility of a substitution like this in the context of a visual data analysis task involving travel, and measure the impact on cybersickness as well as the general task performance and presence. In the conducted user study ( n=52), surprisingly, and partially in contradiction to existing work, we found no significant differences for those core measures between the control condition without a virtual table and the condition containing a virtual table. However, the results also support the inclusion of a virtual table in desk-based use cases.

Immersive visualization (IV) fosters the creation of mental images of a data set, a scene, a procedure, etc. We devise an initial version of a design space for categorizing workflows that take advantage of IV. From this categorization, specific requirements for an actual, seamless IV-integration can be derived. We validate the design space with three workflows investigated in our research projects.

The use of non-verbal vocal input (NVVI) as a hand-free trigger approach has proven to be valuable in previous work [7]. Nevertheless, BlowClick's original detection method is vulnerable to false positives and, thus, is limited in its potential use, e.g., together with acoustic feedback for the trigger. Therefore, we extend the existing approach by adding common machine learning methods. We found that a support vector machine (SVM) with Gaussian kernel performs best for detecting blowing with at least the same latency and more precision as before. Furthermore, we added acoustic feedback to the NVVI trigger, which increases the user's confidence. To evaluate the advanced trigger technique, we conducted a user study (n = 33). The results confirm that it is a reliable trigger; alone and as part of a hands-free point-and-click interface.

To use the full potential of immersive data analysis when wearing a head-mounted display, the user has to be able to navigate through the spatial data. We collected, developed and evaluated 5 different handsfree navigation methods that are usable while seated in the analyst's usual workplace. All methods meet the requirements of being easy to learn and inexpensive to integrate into existing workplaces. We conducted a user study with 23 participants which showed that a body leaning metaphor and an accelerometer pedal metaphor performed best within the given task.

Virtual Reality (VR) has been an active field of research for several decades, with 3D interaction and 3D User Interfaces (UIs) as important sub-disciplines. However, the development of 3D interaction techniques and in particular combining several of them to construct complex and usable 3D UIs remains challenging, especially in a VR context. In addition, there is currently only limited reusable software for implementing such techniques in comparison to traditional 2D UIs. To overcome this issue, we present ViSTA Widgets, a software framework for creating 3D UIs for immersive virtual environments. It extends the ViSTA VR framework by providing functionality to create multi-device, multi-focus-strategy interaction building blocks and means to easily combine them into complex 3D UIs. This is realized by introducing a device abstraction layer along sophisticated focus management and functionality to create novel 3D interaction techniques and 3D widgets. We present the framework and illustrate its effectiveness with code and application examples accompanied by performance evaluations.

Abstract Interactive analysis of 3D relational data is challenging. A common way of representing such data are node‐link diagrams as they support analysts in achieving a mental model of the data. However, naïve 3D depictions of complex graphs tend to be visually cluttered, even more than in a 2D layout. This makes graph exploration and data analysis less efficient. This problem can be addressed by edge bundling. We introduce a 3D cluster‐based edge bundling algorithm that is inspired by the force‐directed edge bundling (FDEB) algorithm [ HvW09b ] and fulfills the requirements to be embedded in an interactive framework for spatial data analysis. It is parallelized and scales with the size of the graph regarding the runtime. Furthermore, it maintains the edge's model and thus supports rendering the graph in different structural styles. We demonstrate this with a graph originating from a simulation of the function of a macaque brain.