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A common problem in Virtual Reality is latency. Especially for head tracking, latency can lead to a lower immersion. Prediction can be used to reduce the effect of latency. However, for good results the prediction process has to be reliably fast and accurate. Human motion is not homogeneous and humans often tend to change the way they move. Prediction models can be designed for these special motion types. To combine the special models, a multiple model approach is presented. It constantly evaluates the quality of the different specialized motion prediction and adjusts the set of motion models. We propose two variants, and compare them to a reference prediction algorithm.

While visual feedback is dominant in Virtual Environments, the use of other modalities like haptics and acoustics can enhance believability, immersion, and interaction performance. Haptic feedback is especially helpful for many interaction tasks like working with medical or precision tools. However, unlike visual and auditory feedback, haptic reproduction is often difficult to achieve due to hardware limitations. This article describes a user study to examine how auditory feedback can be used to substitute haptic feedback when interacting with a vibrating tool. Participants remove some target material with a round-headed drill while avoiding damage to the underlying surface. In the experiment, varying combinations of surface force feedback, vibration feedback, and auditory feedback are used. We describe the design of the user study and present the results, which show that auditory feedback can compensate the lack of haptic feedback.

In this contribution, we present an immersive visualization of room acoustical simulation data. In contrast to the commonly employed external viewpoint, our approach places the user inside the visualized data. The main problem with this technique is the occlusion of some data points by others. We present different solutions for this problem that allow an interactive analysis of the simulation data.

In this paper we present a simulator for two-handed haptic interaction. As an application example, we chose a medical scenario that requires simultaneous interaction with a hand and a needle on a simulated patient. The system combines bimanual haptic interaction with a physics-based soft tissue simulation. To our knowledge the combination of finite element methods for the simulation of deformable objects with haptic rendering is seldom addressed, especially with two haptic devices in a non-trivial scenario. Challenges are to find a balance between real-time constraints and high computational demands for fidelity in simulation and to synchronize data between system components. The system has been successfully implemented and tested on two different hardware platforms: one mobile on a laptop and another stationary on a semi-immersive VR system. These two platforms have been chosen to demonstrate scaleability in terms of fidelity and costs. To compare performance and estimate latency, we measured timings of update loops and logged event-based timings of several components in the software.

We present a comprehensive 3D sketch recognition framework for interaction within Virtual Environments that allows to trigger commands by drawing symbols, which are recognized by a multi-level analysis. It proceeds in three steps: The segmentation partitions each input line into meaningful segments, which are then recognized as a primitive shape, and finally analyzed as a whole sketch by a symbol matching step. The whole framework is configurable over well-defined interfaces, utilizing a fuzzy logic algorithm for primitive shape learning and a textual description language to define compound symbols. It allows an individualized interaction approach that can be used without much training and provides a good balance between abstraction and intuition. We show the real-time applicability of our approach by performance measurements.

During the last decade, Virtual Reality (VR) systems have progressed from primary laboratory experiments into serious and valuable tools. Thereby, the amount of useful applications has grown in a large scale, covering conventional use, e.g., in science, design, medicine and engineering, as well as more visionary applications such as creating virtual spaces that aim to act real. However, the high capabilities of today’s virtual reality systems are mostly limited to firstclass visual rendering, which directly disqualifies them for immersive applications. For general application, though, VR-systems should feature more than one modality in order to boost its range of applications. The CAVE-like immersive environment that is run at RWTH Aachen University comprises state-of-the-art visualization and auralization with almost no constraints on user interaction. In this article a summary of the concept, the features and the performance of our VR-system is given. The system features a 3D sketching interface that allows controlling the application in a very natural way by simple gestures. The sound rendering engine relies on present-day knowledge of Virtual Acoustics and enables a physically accurate simulation of sound propagation in complex environments, including important wave effects such as sound scattering, airborne sound insulation between rooms and sound diffraction. In spite of this realistic sound field rendering, not only spatially distributed and freely movable sound sources and receivers are supported, but also modifications and manipulations of the environment itself. The auralization concept is founded on pure FIR filtering which is realized by highly parallelized non-uniformly partitioned convolutions. A dynamic crosstalk cancellation system performs the sound reproduction that delivers binaural signals to the user without the need of headphones. The significant computational complexity is handled by distributed computation on PCclusters that drive the simulation in real-time even for huge audio-visual scenarios.

This paper presents a sketch-based interface for interactive modification of architectural design prototypes inside a virtual environment. The user can move around in the scenery and create line drawings to add annotations. In order to modify or extend the scenery, she can sketch command symbols, which are then recognized by the application to trigger the application defined commands. This allows the user to modify existing objects in the scene as well as to create new ones. This sketch based interface is supposed to act as a front-end application for architects in order to have a tool for the interactive reconfiguration of rooms and interior in a visual-acoustic virtual environment.