Human Interaction in Multi-User Virtual Reality

In this paper we will present an immersive multiuser environment for studying joint action and social interaction. Besides the technical challenges of immersing multiple persons into a single virtual environment, additional research questions arise: Which parameters are coordinated during a joint action transportation task? In what way does the visual absence of the interaction partner affect the coordination task? What role does haptic feedback play in a transportation task? To answer these questions and to test the new experimental environment we instructed pairs of subjects to perform a classical joint action transportation task: carrying a stretcher through an obstacle course. With this behavioral experiment we demonstrated that joint action behavior (resulting from the coordination task) is a stable process. Even though visual and haptic information about the interaction partner were reduced, humans quickly compensated for the lack of information. After a short time they did not perform significantly differently from normal joint action behavior

Walking with virtual humans : understanding human response to virtual humanoids' appearance and behaviour while navigating in immersive VR

In this thesis, we present a set of studies whose results have allowed us to analyze how to improve the realism, navigation, and behaviour of the avatars in an immersive virtual reality environment. In our simulations, participants must perform a series of tasks and we have analyzed perceptual and behavioural data. The results of the studies have allowed us to deduce what improvements are needed to be incorporated to the original simulations, in order to enhance the perception of realism, the navigation technique, the rendering of the avatars, their behaviour or their animations. The most reliable technique for simulating avatars’ behaviour in a virtual reality environment should be based on the study of how humans behave within the environment. For this purpose, it is necessary to build virtual environments where participants can navigate safely and comfortably with a proper metaphor and, if the environment is populated with avatars, simulate their behaviour accurately. All these aspects together will make the participants behave in a way that is closer to how they would behave in the real world. Besides, the integration of these concepts could provide an ideal platform to develop different types of applications with and without collaborative virtual reality such as emergency simulations, teaching, architecture, or designing. In the first contribution of this thesis, we carried out an experiment to study human decision making during an evacuation. We were interested to evaluate to what extent the behaviour of a virtual crowd can affect individuals' decisions. From the second contribution, in which we studied the perception of realism with bots and humans performing just locomotion or varied animations, we can conclude that the combination of having human-like avatars with animation variety can increase the overall realism of a crowd simulation, trajectories and animation. The preliminary study presented in the third contribution of this thesis showed that realistic rendering of the environment and the avatars do not appear to increase the perception of realism in the participants, which is consistent with works presented previously. The preliminary results in our walk-in-place contribution showed a seamless and natural transition between walk-in-place and normal walk. Our system provided a velocity mapping function that closely resembles natural walk. We observed through a pilot study that the system successfully reduces motion sickness and enhances immersion. Finally, the results of the contribution related to locomotion in collaborative virtual reality showed that animation synchronism and footstep sound of the avatars representing the participants do not seem to have a strong impact in terms of presence and feeling of avatar control. However, in our experiment, incorporating natural animations and footstep sound resulted in smaller clearance values in VR than previous work in the literature. The main objective of this thesis was to improve different factors related to virtual reality experiences to make the participants feel more comfortable in the virtual environment. These factors include the behaviour and appearance of the virtual avatars and the navigation through the simulated space in the experience. By increasing the realism of the avatars and facilitating navigation, high scores in presence are achieved during the simulations. This provides an ideal framework for developing collaborative virtual reality applications or emergency simulations that require participants to feel as if they were in real life.En aquesta tesi, es presenta un conjunt d'estudis els resultats dels quals ens han permès analitzar com millorar el realisme, la navegació i el comportament dels avatars en un entorn de realitat virtual immersiu. En les nostres simulacions, els participants han de realitzar una sèrie de tasques i hem analitzat dades perceptives i de comportament mentre les feien. Els resultats dels estudis ens han permès deduir quines millores són necessàries per a ser incorporades a les simulacions originals, amb la finalitat de millorar la percepció del realisme, la tècnica de navegació, la representació dels avatars, el seu comportament o les seves animacions. La tècnica més fiable per simular el comportament dels avatars en un entorn de realitat virtual hauria de basar-se en l'estudi de com es comporten els humans dins de l¿entorn virtual. Per a aquest propòsit, és necessari construir entorns virtuals on els participants poden navegar amb seguretat i comoditat amb una metàfora adequada i, si l¿entorn està poblat amb avatars, simular el seu comportament amb precisió. Tots aquests aspectes junts fan que els participants es comportin d'una manera més pròxima a com es comportarien en el món real. A més, la integració d'aquests conceptes podria proporcionar una plataforma ideal per desenvolupar diferents tipus d'aplicacions amb i sense realitat virtual col·laborativa com simulacions d'emergència, ensenyament, arquitectura o disseny. En la primera contribució d'aquesta tesi, vam realitzar un experiment per estudiar la presa de decisions durant una evacuació. Estàvem interessats a avaluar en quina mesura el comportament d'una multitud virtual pot afectar les decisions dels participants. A partir de la segona contribució, en la qual estudiem la percepció del realisme amb robots i humans que realitzen només una animació de caminar o bé realitzen diverses animacions, vam arribar a la conclusió que la combinació de tenir avatars semblants als humans amb animacions variades pot augmentar la percepció del realisme general de la simulació de la multitud, les seves trajectòries i animacions. L'estudi preliminar presentat en la tercera contribució d'aquesta tesi va demostrar que la representació realista de l¿entorn i dels avatars no semblen augmentar la percepció del realisme en els participants, que és coherent amb treballs presentats anteriorment. Els resultats preliminars de la nostra contribució de walk-in-place van mostrar una transició suau i natural entre les metàfores de walk-in-place i caminar normal. El nostre sistema va proporcionar una funció de mapatge de velocitat que s'assembla molt al caminar natural. Hem observat a través d'un estudi pilot que el sistema redueix amb èxit el motion sickness i millora la immersió. Finalment, els resultats de la contribució relacionada amb locomoció en realitat virtual col·laborativa van mostrar que el sincronisme de l'animació i el so dels avatars que representen els participants no semblen tenir un fort impacte en termes de presència i sensació de control de l'avatar. No obstant això, en el nostre experiment, la incorporació d'animacions naturals i el so de passos va donar lloc a valors de clearance més petits en RV que treballs anteriors ja publicats. L'objectiu principal d'aquesta tesi ha estat millorar els diferents factors relacionats amb experiències de realitat virtual immersiva per fer que els participants se sentin més còmodes en l'entorn virtual. Aquests factors inclouen el comportament i l'aparença dels avatars i la navegació a través de l'entorn virtual. En augmentar el realisme dels avatars i facilitar la navegació, s'aconsegueixen altes puntuacions en presència durant les simulacions. Això proporciona un marc ideal per desenvolupar aplicacions col·laboratives de realitat virtual o simulacions d'emergència que requereixen que els participants se sentin com si estiguessin en la vida realPostprint (published version

Interaction design for multi-user virtual reality systems: An automotive case study

Virtual reality (VR) technology have become ever matured today. Various research and practice have demonstrated the potential benefits of using VR in different application area of manufacturing, such as in factory layout planning, product design, training, etc. However, along with the new possibilities brought by VR, comes with the new ways for users to communicate with the computer system. The human computer interaction design for these VR systems becomes pivotal to the smooth integration. In this paper, it reports the study that investigates interaction design strategies for the multi-user VR system used in manufacturing context though an automotive case study

Virtual reality obstacle crossing: adaptation, retention and transfer to the physical world

Virtual reality (VR) paradigms are increasingly being used in movement and exercise sciences with the aim to enhance motor function and stimulate motor adaptation in healthy and pathological conditions. Locomotor training based in VR may be promising for motor skill learning, with transfer of VR skills to the physical world in turn required to benefit functional activities of daily life. This PhD project aims to examine locomotor adaptations to repeated VR obstacle crossing in healthy young adults as well as transfers to the untrained limb and the physical world, and retention potential of the learned skills. For these reasons, the current thesis comprises three studies using controlled VR obstacle crossing interventions during treadmill walking. In the first and second studies we investigated adaptation to crossing unexpectedly appearing virtual obstacles, with and without feedback about crossing performance, and its transfer to the untrained leg. In the third study we investigated transfer of virtual obstacle crossing to physical obstacles of similar size to the virtual ones, that appeared at the same time point within the gait cycle. We also investigated whether the learned skills can be retained in each of the environments over one week. In all studies participants were asked to walk on a treadmill while wearing a VR headset that represented their body as an avatar via real-time synchronised optical motion capture. Participants had to cross virtual and/or physical obstacles with and without feedback about their crossing performance. If applicable, feedback was provided based on motion capture immediately after virtual obstacle crossing. Toe clearance, margin of stability, and lower extremity joint angles in the sagittal plane were calculated for the crossing legs to analyse adaptation, transfer, and retention of obstacle crossing performance. The main outcomes of the first and second studies were that crossing multiple virtual obstacles increased participants’ dynamic stability and led to a nonlinear adaptation of toe clearance that was enhanced by visual feedback about crossing performance. However, independent of the use of feedback, no transfer to the untrained leg was detected. Moreover, despite significant and rapid adaptive changes in locomotor kinematics with repeated VR obstacle crossing, results of the third study revealed limited transfer of learned skills from virtual to physical obstacles. Lastly, despite full retention over one week in the virtual environment we found only partial retention when crossing a physical obstacle while walking on the treadmill. In summary, the findings of this PhD project confirmed that repeated VR obstacle perturbations can effectively stimulate locomotor skill adaptations. However, these are not transferable to the untrained limb irrespective of enhanced awareness and feedback. Moreover, the current data provide evidence that, despite significant adaptive changes in locomotion kinematics with repeated practice of obstacle crossing under VR conditions, transfer to and retention in the physical environment is limited. It may be that perception-action coupling in the virtual environment, and thus sensorimotor coordination, differs from the physical world, potentially inhibiting retained transfer between those two conditions. Accordingly, VR-based locomotor skill training paradigms need to be considered carefully if they are to replace training in the physical world

Conceptualizing Immersion for Individual Learning in Virtual Reality

Immersive virtual reality technology (VR) receives more and more attention, especially since the release of the Oculus Rift (development kit 2) in2016. This technology is not only used in the gaming industry but also in serious contexts such as product design or education. The creation of high immersion is commonly said to be the special characteristic of VR. We consider two perspectives on immersion: firstly, immersion in the task and, secondly, immersion in the technology. Our work focuses on immersion as part of the learning related theory of cognitive absorption to examine the theoretical difference between task and technology immersion in the case of individual learning with immersive VR technology. We conducted an explorative Grounded Theory approach with 10 in-depth interviews based on first-hand experience with a self-developed immersive VR application. We propose theoretical and design implications for how VR can potentially enhance individual learning

08231 Abstracts Collection -- Virtual Realities

From 1st to 6th June 2008, the Dagstuhl Seminar 08231 ``Virtual Realities\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. Virtual Reality (VR) is a multidisciplinary area of research aimed at interactive human-computer mediated simulations of artificial environments. Typical applications include simulation, training, scientific visualization, and entertainment. An important aspect of VR-based systems is the stimulation of the human senses -- typically sight, sound, and touch -- such that a user feels a sense of presence (or immersion) in the virtual environment. Different applications require different levels of presence, with corresponding levels of realism, sensory immersion, and spatiotemporal interactive fidelity. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. Links to extended abstracts or full papers are provided, if available

Analysis domain model for shared virtual environments

The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model