Not Alone Here?! Scalability and User Experience of Embodied Ambient Crowds in Distributed Social Virtual Reality

Handwriting for Text Input and the Impact of XR Displays, Surface Alignments, and Sentence Complexities

Text input is desirable across various eXtended Reality (XR) use cases and is particularly crucial for knowledge and office work. This article compares handwriting text input between Virtual Reality (VR) and Video See-Through Augmented Reality (VST AR), facilitated by physically aligned and mid-air surfaces when writing simple and complex sentences. In a $2\times 2\times 2$ experimental design, 72 participants performed two ten-minute handwriting sessions, each including ten simple and ten complex sentences representing text input in real-world scenarios. Our developed handwriting application supports different XR displays, surface alignments, and handwriting recognition based on digital ink. We evaluated usability, user experience, task load, text input performance, and handwriting style. Our results indicate high usability with a successful transfer of handwriting skills to the virtual domain. XR displays and surface alignments did not impact text input speed and error rate. However, sentence complexities did, with participants achieving higher input speeds and fewer errors for simple sentences (17.85 WPM, 0.51% MSD ER) than complex sentences (15.07 WPM, 1.74% MSD ER). Handwriting on physically aligned surfaces showed higher learnability and lower physical demand, making them more suitable for prolonged handwriting sessions. Handwriting on mid-air surfaces yielded higher novelty and stimulation ratings, which might diminish with more experience. Surface alignments and sentence complexities significantly affected handwriting style, leading to enlarged and more connected cursive writing in both mid-air and for simple sentences. The study also demonstrated the benefits of using XR controllers in a pen-like posture to mimic styluses and pressure-sensitive tips on physical surfaces for input detection. We additionally provide a phrase set of simple and complex sentences as a basis for future text input studies, which can be expanded and adapted.

Text Input for Non-Stationary XR Workspaces: Investigating Tap and Word-Gesture Keyboards in Virtual and Augmented Reality

This article compares two state-of-the-art text input techniques between non-stationary virtual reality (VR) and video see-through augmented reality (VST AR) use-cases as XR display condition. The developed contact-based mid-air virtual tap and wordgesture (swipe) keyboard provide established support functions for text correction, word suggestions, capitalization, and punctuation. A user evaluation with 64 participants revealed that XR displays and input techniques strongly affect text entry performance, while subjective measures are only influenced by the input techniques. We found significantly higher usability and user experience ratings for tap keyboards compared to swipe keyboards in both VR and VST AR. Task load was also lower for tap keyboards. In terms of performance, both input techniques were significantly faster in VR than in VST AR. Further, the tap keyboard was significantly faster than the swipe keyboard in VR. Participants showed a significant learning effect with only ten sentences typed per condition. Our results are consistent with previous work in VR and optical see-through (OST) AR, but additionally provide novel insights into usability and performance of the selected text input techniques for VST AR. The significant differences in subjective and objective measures emphasize the importance of specific evaluations for each possible combination of input techniques and XR displays to provide reusable, reliable, and high-quality text input solutions. With our work, we form a foundation for future research and XR workspaces. Our reference implementation is publicly available to encourage replicability and reuse in future XR workspaces.

Output-Sensitive Avatar Representations for Immersive Telepresence

In this article, we propose a system design and implementation for output-sensitive reconstruction, transmission and rendering of 3D video avatars in distributed virtual environments. In our immersive telepresence system, users are captured by multiple RGBD sensors connected to a server that performs geometry reconstruction based on viewing feedback from remote telepresence parties. This feedback and reconstruction loop enables visibility-aware level-of-detail reconstruction of video avatars regarding geometry and texture data, and considers individual and groups of collocated users. Our evaluation reveals that our approach leads to a significant reduction of reconstruction times, network bandwidth requirements and round-trip times as well as rendering costs in many situations.

Virtual Reality Adaptation Using Electrodermal Activity to Support the User Experience

Virtual reality is increasingly used for tasks such as work and education. Thus, rendering scenarios that do not interfere with such goals and deplete user experience are becoming progressively more relevant. We present a physiologically adaptive system that optimizes the virtual environment based on physiological arousal, i.e., electrodermal activity. We investigated the usability of the adaptive system in a simulated social virtual reality scenario. Participants completed an n-back task (primary) and a visual detection (secondary) task. Here, we adapted the visual complexity of the secondary task in the form of the number of non-player characters of the secondary task to accomplish the primary task. We show that an adaptive virtual reality can improve users’ comfort by adapting to physiological arousal regarding the task complexity. Our findings suggest that physiologically adaptive virtual reality systems can improve users’ experience in a wide range of scenarios.

Virtual conference design: features and obstacles

The Covid-19 pandemic has forced a change in the way people work, and the location that they work from. The impact has caused significant disruption to education, the work environment and how social interactions take place. Online user habits have also changed due to lockdown restrictions and virtual conferencing software has become a vital cog in team communication. In result, a spate in software solutions have emerged in order to support the challenges of remote learning and working. The conferencing software landscape is now a core communication solution for company-wide interaction, team discussions, screen sharing and face-to-face contact. Yet the number of existing platforms is diverse. In this article, a systematic literature review investigation on virtual conferencing is presented. As output from the analysis, 67 key features and 74 obstacles users experience when interacting with virtual conferencing technologies are identified from 60 related open-source journal articles from 5 digital library repositories.

Avatars for Teleconsultation: Effects of Avatar Embodiment Techniques on User Perception in 3D Asymmetric Telepresence

A 3D Telepresence system allows users to interact with each other in a virtual, mixed, or augmented reality (VR, MR, AR) environment, creating a shared space for collaboration and communication. There are two main methods for representing users within these 3D environments. Users can be represented either as point cloud reconstruction-based avatars that resemble a physical user or as virtual character-based avatars controlled by tracking the users' body motion. This work compares both techniques to identify the differences between user representations and their fit in the reconstructed environments regarding the perceived presence, uncanny valley factors, and behavior impression. Our study uses an asymmetric VR/AR teleconsultation system that allows a remote user to join a local scene using VR. The local user observes the remote user with an AR head-mounted display, leading to facial occlusions in the 3D reconstruction. Participants perform a warm-up interaction task followed by a goal-directed collaborative puzzle task, pursuing a common goal. The local user was represented either as a point cloud reconstruction or as a virtual character-based avatar, in which case the point cloud reconstruction of the local user was masked. Our results show that the point cloud reconstruction-based avatar was superior to the virtual character avatar regarding perceived co-presence, social presence, behavioral impression, and humanness. Further, we found that the task type partly affected the perception. The point cloud reconstruction-based approach led to higher usability ratings, while objective performance measures showed no significant difference. We conclude that despite partly missing facial information, the point cloud-based reconstruction resulted in better conveyance of the user behavior and a more coherent fit into the simulation context.

AudienceMR: Extending the Local Space for Large-Scale Audience with Mixed Reality for Enhanced Remote Lecturer Experience

AudienceMR is designed as a multi-user mixed reality space that seamlessly extends the local user space to become a large, shared classroom where some of the audience members are seen seated in a real space, and more members are seen through an extended portal. AudienceMR can provide a sense of the presence of a large-scale crowd/audience with the associated spatial context. In contrast to virtual reality (VR), however, with mixed reality (MR), a lecturer can deliver content or conduct a performance from a real, actual, comfortable, and familiar local space, while interacting directly with real nearby objects, such as a desk, podium, educational props, instruments, and office materials. Such a design will elicit a realistic user experience closer to an actual classroom, which is currently prohibitive owing to the COVID-19 pandemic. This paper validated our hypothesis by conducting a comparative experiment assessing the lecturer’s experience with two independent variables: (1) an online classroom platform type, i.e., a 2D desktop video teleconference, a 2D video screen grid in VR, 3D VR, and AudienceMR, and (2) a student depiction, i.e., a 2D upper-body video screen and a 3D full-body avatar. Our experiment validated that AudienceMR exhibits a level of anxiety and fear of public speaking closer to that of a real classroom situation, and a higher social and spatial presence than 2D video grid-based solutions and even 3D VR. Compared to 3D VR, AudienceMR offers a more natural and easily usable real object-based interaction. Most subjects preferred AudienceMR over the alternatives despite the nuisance of having to wear a video see-through headset. Such qualities will result in information conveyance and an educational efficacy comparable to those of a real classroom, and better than those achieved through popular 2D desktop teleconferencing or immersive 3D VR solutions.

A history of crowd simulation: the past, evolution, and new perspectives

This paper aims to discuss the past, evolution, and new perspectives in crowd simulation. Many work have been produced and published in this area that was launched approximately 30 years ago. In this paper, we re-visited the main aspects of the area, presenting the periods and evolution we had in the past. In addition, we also discuss the present and possible trends for the future.

Augmented Virtual Teleportation for High-Fidelity Telecollaboration

Telecollaboration involves the teleportation of a remote collaborator to another real-world environment where their partner is located. The fidelity of the environment plays an important role for allowing corresponding spatial references in remote collaboration. We present a novel asymmetric platform, Augmented Virtual Teleportation (AVT), which provides high-fidelity telepresence of a remote VR user (VR-Traveler) into a real-world collaboration space to interact with a local AR user (AR-Host). AVT uses a 360° video camera (360-camera) that captures and live-streams the omni-directional scenes over a network. The remote VR-Traveler watching the video in a VR headset experiences live presence and co-presence in the real-world collaboration space. The VR-Traveler's movements are captured and transmitted to a 3D avatar overlaid onto the 360-camera which can be seen in the AR-Host's display. The visual and audio cues for each collaborator are synchronized in the Mixed Reality Collaboration space (MRC-space), where they can interactively edit virtual objects and collaborate in the real environment using the real objects as a reference. High fidelity, real-time rendering of virtual objects and seamless blending into the real scene allows for unique mixed reality use-case scenarios. Our working prototype has been tested with a user study to evaluate spatial presence, co-presence, and user satisfaction during telecollaboration. Possible applications of AVT are identified and proposed to guide future usage.

Mind the Gap: The Underrepresentation of Female Participants and Authors in Virtual Reality Research

A common goal of human-subject experiments in virtual reality (VR) research is evaluating VR hardware and software for use by the general public. A core principle of human-subject research is that the sample included in a given study should be representative of the target population; otherwise, the conclusions drawn from the findings may be biased and may not generalize to the population of interest. In order to assess whether characteristics of participants in VR research are representative of the general public, we investigated participant demographic characteristics from human-subject experiments in the Proceedings of the IEEE Virtual Reality Conferences from 2015-2019. We also assessed the representation of female authors. In the 325 eligible manuscripts, which presented results from 365 human-subject experiments, we found evidence of significant underrepresentation of women as both participants and authors. To investigate whether this underrepresentation may bias researchers' findings, we then conducted a meta-analysis and meta-regression to assess whether demographic characteristics of study participants were associated with a common outcome evaluated in VR research: the change in simulator sickness following head-mounted display VR exposure. As expected, participants in VR studies using HMDs experienced small but significant increases in simulator sickness. However, across the included studies, the change in simulator sickness was systematically associated with the proportion of female participants. We discuss the negative implications of conducting experiments on non-representative samples and provide methodological recommendations for mitigating bias in future VR research.