In this paper, I address the question as to why participants tend to respond realistically to situations and events portrayed within an immersive virtual reality system. The idea is put forward, based on the experience of a large number of experimental studies, that there are two orthogonal components that contribute to this realistic response. The first is ‘being there’, often called ‘presence’, the qualia of having a sensation of being in a real place. We call this place illusion (PI). Second, plausibility illusion (Psi) refers to the illusion that the scenario being depicted is actually occurring. In the case of both PI and Psi the participant knows for sure that they are not ‘there’ and that the events are not occurring. PI is constrained by the sensorimotor contingencies afforded by the virtual reality system. Psi is determined by the extent to which the system can produce events that directly relate to the participant, the overall credibility of the scenario being depicted in comparison with expectations. We argue that when both PI and Psi occur, participants will respond realistically to the virtual reality.

/pdf/place-illusion-and-plausibility-can-lead-to-realistic-1hpdya0yai.pdf

Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments

The Transmission Control Protocol.

/pdf/enhancing-our-lives-with-immersive-virtual-reality-496gj7y20r.pdf

Enhancing Our Lives with Immersive Virtual Reality

Over the last 20 years research has been done on the question of how egocentric distances, i.e., the subjectively reported distance from a human observer to an object, are perceived in virtual environments. This review surveys the existing literature on empirical user studies on this topic. In summary, there is a mean estimation of egocentric distances in virtual environments of about 74p of the modeled distances. Many factors possibly influencing distance estimates were reported in the literature. We arranged these factors into four groups, namely measurement methods, technical factors, compositional factors, and human factors. The research on these factors is summarized, conclusions are drawn, and promising areas for future research are outlined.

https://dl.acm.org/doi/pdf/10.1145/2543581.2543590

The perception of egocentric distances in virtual environments - A review

This paper presents an experiment designed to investigate the impact of scommunication in an immersive virtual environment.Participants were paired by gender and were randomly assigned to a CAVE-like system or a head-mounted display. Both were represented by a humanoid avatar in the shared 3D environment. The visual appearance of the avatars was either basic and genderless (like a "match-stick" figure), or more photorealistic and gender-specific. Similarly, eye gaze behavior was either random or inferred from voice, to reflect different levels of behavioral realism.Our comparative analysis of 48 post-experiment questionnaires confirms earlier findings from non-immersive studies using semi-photorealistic avatars, where inferred gaze significantly outperformed random gaze. However responses to the lower-realism avatar are adversely affected by inferred gaze, revealing a significant interaction effect between appearance and behavior. We discuss the importance of aligning visual and behavioral realism for increased avatar effectiveness.

/pdf/the-impact-of-avatar-realism-and-eye-gaze-control-on-3gm483hxq5.pdf

The impact of avatar realism and eye gaze control on perceived quality of communication in a shared immersive virtual environment

Does greater visual realism induce greater participant presence in immersive virtual environments (VE)? Presence refers to how realistically participants respond to the environment as well as their subjective sense of being in the place depicted by the VE. Thirty-three people were exposed for three minutes to a virtual environment depicting a precipice using a head-tracked head-mounted display system. Seventeen of them saw the environment rendered with real-time recursive ray tracing (RT) that included shadows and reflections of their virtual body, and the remainder experienced the same environment rendered with ray casting (RC), which did not include shadows and reflections. Participants completed a presence questionnaire immediately after their experience, and physiological responses (skin conductance and electrocardiogram) were recorded throughout. Results show that subjective presence was higher for the RT environment than for the RC one and that higher stress was induced in the RT environment compared to the RC one.

/pdf/visual-realism-enhances-realistic-response-in-an-immersive-400fyshcxd.pdf

Visual Realism Enhances Realistic Response in an Immersive Virtual Environment - Part 2

The extent to which the addition of haptic communication between human users in a stared virtual environment (SVE) contributes to the shared experience of the users has not received much attention in the literature, In this paper we describe a demonstration of and an expenmental study on haptic interaction between two users over a network of significant physical distance and a number of Network hops. A number of techniques to mitigate instability of the haptic interactions induced by network latency are presented An experiment to evaluate the use of haptics in a coilborative situation mediated by a networked virtual environment is examined The experimental subjects were to cooperate in lifting a virtual box together under one of four conditions in a between-groups design. Questionnaires were used to report the ease with which they could perform the task and the subjective levels of presence ants copresence experienced This extends earlier work by the authors to consider the possibility of haptic collaboration under real network conditions with a Number of improvements. Using the technology described in-this paper, transatlantic touch was successfully demonstrated between the Touch lab at Massachusetts Instatute of Technology, USA and Virtual Environments and Computer Graphics (VECG) lab at University Collegc London (UCL), UK in 2000, It as also presented at the Internet II demonstration meeting in 2002 between University of Southern California and the Massachusetts Instrtute of Technology.

/pdf/transatlantic-touch-a-study-of-haptic-collaboration-over-128wh7ltaq.pdf

Transatlantic touch: a study of haptic collaboration over long distance

This paper describes a study of remote collaboration between people in a shared virtual environment. Seventeen subjects were recruited at University College London, who worked with a confederate at University of North Carolina Chapel Hill. Each pair was required to negotiate the task of handling an object together, and moving a few metres into a building. The DIVE system was used throughout, and the network support was Internet-2. This was an observational study to examine the extent to which such collaboration was possible, to explore the limitations of DIVE within this context, and to examine the relationship between several variables such as co-presence and task performance. The results suggest that although the task is possible under this framework, it could only be achieved by various software tricks within the DIVE framework. A new Virtual Environment system is required that has better knowledge of network performance, and that supports shared object manipulation across a network. The participant-study suggests that co-presence, the sense of being together with another person, was significantly and positively correlated with task performance.

/pdf/collaboration-in-tele-immersive-environments-1ln15r2y3p.pdf

Collaboration in tele-immersive environments

The Distributed Interactive Virtual Environment (DIVE) system is a mature toolkit that has been used for prototyping many collaborative virtual environment (CVE) applications [3] Until recently, support for immersive systems has been limited to custom support for specific installations and the emphasis has been on broad support for desktop interfaces Recently we have ported DIVE to the CAVElibTM environment and this paper describes application programming support for immersive users and our experience in using wide-area distributed applications involving immersive projection technologies The resulting toolkit provides a very flexible system with which to build distributed VE applications involving a variety of platforms and interfaces

/pdf/spelunking-experiences-using-the-dive-system-on-cave-like-2lqahjqbyu.pdf

Spelunking: experiences using the DIVE system on CAVE-like platforms

This paper describes an experiment that examines the influence of visual realism on reported presence. 33 participants experienced two different renderings of a virtual environment that depicts a pit in the centre of a room, in a head-tracked head-mounted display. The environment was rendered using parallel ray tracing at 15fps,mbut in one condition ray casting (RC) was used achieving a result equivalent to OpenGL based per-pixel local illumination, and in the second full recursive ray tracing (RT). The participants were randomly allocated to two groups -- one that experienced RC first followed by RT, and the second group in the opposite order. Reported presence was obtained by questionnaires following each session. The results indicate that reported presence, in terms of the 'sense of being there' was significantly higher for the RT than for the RC condition.

http://www0.cs.ucl.ac.uk/staff/m.slater/Papers/sp051-khanna.pdf

J. Mortensen

Papers

Visual Realism Enhances Realistic Response in an Immersive Virtual Environment - Part 2

Transatlantic touch: a study of haptic collaboration over long distance

Collaboration in tele-immersive environments

Spelunking: experiences using the DIVE system on CAVE-like platforms

Presence in response to dynamic visual realism: a preliminary report of an experiment study