Dynamic Interactions for Networked Virtual Environments

Abstract

The field of networked virtual environments has been an active area of research in the past decades. The increasing power of contemporary computers and the lowering of hardware and connectivity costs permits people to have this technology available in their homes and workplaces. As a result, several applications and prototypes are successfully being used in several fields. Most of the research and developments have, however, been technology driven and as a result one of the main components, interaction, is much less explored. In this dissertation we focus on realizing more realistic virtual experiences by narrowing the gap between real-life and virtual world interaction possibilities. In contrast to ad hoc approaches, we also seek to provide a more general and reusable solution. The interactive object approach provides such a solution by employing a general purpose interaction mechanism for every kind of interaction in the virtual world. This mechanism relies heavily on a feature modeling approach that allows objects to describe their own interaction possibilities.As a result, the interactions become application independent and objects unknown to the application can be inserted at run time. The problem of realistic interactions is, however, not limited to representation and execution of interactions. It requires the consideration of several related fields, such as realistic simulation and animation, user embodiment and human computer interaction as well. Therefore, in a second phase, we developed and integrated the ExtReAM library into the interaction framework. This platform-independent library allows us to improve realism by enabling physical simulation and more dynamic animations for objects and user embodiments. Furthermore, it allows objects to contain physical properties and actions as well. By combining realistic simulation with our dynamic interaction mechanism, much more lively virtual worlds can be achieved with minimal effort, which can result in better virtual experiences and higher levels of presence if used properly. As more natural interaction techniques can increase the user’s feeling of being immersed in the virtual world, we analyze how our dynamic interaction and animation system can be utilized to create more realistic user embodiment control and interaction techniques. Therefore, we propose two new 3D interaction techniques, utilizing our framework. The first technique allows the user to interact directly in the virtual world by controlling his virtual hand with a 3D input device. We elaborate on how this was established and how this technique can be distributed among the participants with as little bandwidth consumption as possible. The second technique involves a travel technique that provides the user with haptic feedback on what is happening to his virtual counterpart. This was realized by converting rigid body simulation information into force feedback. By means of a formal usability study, we show how this haptic travel method results in an increased feeling of immersion.