EGVE: Eurographics Workshop on Virtual Environments

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Practical Calibration Procedures for Augmented Reality
(The Eurographics Association, 2000) Fuhrmann, Anton; Schmalstieg, Dieter; Purgathofer, Werner; J. D. Mulder and R. van Liere
Augmented Reality overlays computer generated images over the real world. This requires precise knowledge of the viewing projection of the headmounted display (HMD) and its position. Most of the previously published methods are complicated or use special equipment for the calibration process. We present a collection of calibration methods usable for fast and easy calibration of camera parameters, object/camera to tracker transformations, and image rectification, which do not need additional instrumentation or complicated procedures. They are applicable for both see-through and videobased HMDs and have already been successfully implemented in the Studierstube collaborative augmented environment.
A 'plug and play' approach to testing virtual environment interaction techniques
(The Eurographics Association, 2000) Willans, James S.; Harrison, Michael D.; J. D. Mulder and R. van Liere
It is generally agreed that the usability of virtual environment interaction techniques is very poor. One reason for this is because toolkits used by virtual environment developers supply a small number of predefined techniques which are expected to be used regardless of context. In addition, there is no software to facilitate the design and testing of interaction techniques akin to that found for the appearance of the environment. We have developed the Marigold toolset to aid in the systematic design, testing and refining of virtual environment interaction techniques. The toolset uses a visual hybrid specification as a starting point. In this paper we demonstrate how Marigold can be used to aid in determining the suitability of interaction techniques by the rapid testing of alternatives in a 'plug and play' style.
Quality of Service Management for a Media-Enhanced Virtual Meeting Place
(The Eurographics Association, 2000) Pappas-Katsiafas, Evangelos; Smith, Alan; Khan, Kashaf; J. D. Mulder and R. van Liere
This paper details work in progress to produce a Media-enhanced virtual meeting place using Quality of Service Management components to cope with heterogeneous networks and end-systems. In recent years there have been great advances in the fields of Virtual Reality, streamed Audio and Video, and network technology. The combination of these three technologies has the potential to produce a media-rich, realistic environment. Such an environment provides intuitive 3D navigation, interaction with other participants, and they selective audio-visual content. However, varying network performance, processing speed, and workload, have severe effects on the usability, performance and effectiveness of such an application. For this reason a Quality of Service (QoS) management is needed to adapt the application, and maintain usability and effectiveness at the highest level possible, under varying resource conditions.
Beyond Academic Exercises - Strategies Towards a Profitable Implementation of VR Technology in Company Work Processes
(The Eurographics Association, 2000) Reuding, Thomas; J. D. Mulder and R. van Liere
Over the last years virtual reality technology has reached a level of maturity that allows us to integrate it into the primary value chains of industrial work processes. This paper describes the experiences we have had with virtual environments, specifically a four sided CAVE, at BMW. By looking at the use of this technology in car body development and engineering we will try to put initial expectations and day-to-day experience in perspective as well as bring new aspects into the discussion.
The Interaction Between Individuals' Immersive Tendencies and the Sensation of Presence in a Virtual Environment
(The Eurographics Association, 2000) Johns, Cathryn; Nunez, David; Daya, Marc; Sellars, Duncan; Casanueva, Juan; Blake, Edwin; J. D. Mulder and R. van Liere
Witmer and Singer have developed a questionnaire for presence (PQ) as well as an immersive tendencies questionnaire (ITQ). Their research has shown that ITQ scores are positively correlated with PQ scores. This paper reports on an attempt to replicate these findings in a non-immersive, collaborative setting, by creating one virtual environment designed to engender a high sense of presence in users, and one designed to disrupt and decrease the sense of presence felt by users. The major findings of this attempt were firstly that while there was a difference in the two worlds according to the definition of presence, the PQ did not pick up this difference, and secondly that PQ scores were correlated with ITQ scores only in the so-called "high-presence" environment, implying that Witmer and Singer's results hold only under certain conditions.
Developing Effective Navigation Techniques in Virtual 3D Environments
(The Eurographics Association, 2000) Volbracht, Sabine; Domik, Gitta; J. D. Mulder and R. van Liere
As a result of the increasing use of three-dimensional environments and of frequently inefficient possibilities for navigation, a fundamental understanding of navigation is becoming ever more important, both for users as well as for developers of three-dimensional environments. To promote this understanding a rigorous model for navigation was developed. The navigation model contains the relevant factors of influence and determines quality criteria for an efficient navigation. The model is used in a practical study. In this study effective navigation techniques in the application field of teaching/learning environments for children of elementary schools are implemented and evaluated. The simple control of relevant parameters, made possible by the model, can be transferred easily to other ranges of application.
An Asynchronous Architecture to Manage Communication, Display, and User Interaction in Distributed Virtual Environments
(The Eurographics Association, 2000) Fabre, Y.; Pitel, G.; Soubrevilla, L.; Marchand, E.; Géraud, T.; Demaille, A.; J. D. Mulder and R. van Liere
In Distributed Virtual Environments, each machine equally handles the communications over the network, provides the user with a view of the world, and processes her requests. A major issue is to ensure that the network communication does not hinder the interactivity between the machine and the user. In this paper, we present a program designed to achieve this goal, based on tools rarely used in this area.
Accelerometer-Based Motion Tracking for Orchestra Conductor Following
(The Eurographics Association, 2000) Ilmonen, Tommi; Jalkanen, Janne; J. D. Mulder and R. van Liere
In this paper, we discuss the applicability of accelerometers to measuring movement for conductor following. In our application a baton is used to conduct computer animated musicians. The user acts as an orchestra conductor. The baton motion is analyzed for gestures that imply how music and animation should be controlled. The baton motion is tracked with accelerometers. The accelerometers feature inevitable problems for position tracking. Position cannot be measured directly - it needs to be integrated twice from the acceleration. The measurement inaccuracy causes drift over time when velocity and position are calculated via integration. We used two sensors to track motion with six degrees-of-freedom. The problems can be largely overcome by using application-specific signal processing. The drift caused by inaccurate integration is countered by combining leaky integrators and high-pass filters. Rotation is detected by monitoring the direction of gravity.
Towards Immersive Modeling - Challenges and Recommendations: A Workshop Analyzing the Needs of Designers
(The Eurographics Association, 2000) Deisinger, Joachim; Blach, Roland; Wesche, Gerold; Breining, Ralf; Simon, Andreas; J. D. Mulder and R. van Liere
Among the many applications now available in virtual environments (VEs), a modeling application to generate geometry is gaining in relevance. Immersive modeling in VE involves generating drafts and manipulating geometry within an immersive environment such as a CAVE, a Responsive Workbench or other immersive projection technologies. It is a field which will supply product design with new perspectives. This paper describes a workshop in which thirty-six design professionals, active in various branches of product design, tested three different types of prototype modelers. The analysis of their experience will help to improve such modeling applications and to further develop immersive modeling in general.
Continuously-Adaptive Haptic Rendering
(The Eurographics Association, 2000) El-Sana, Jihad; Varshney, Amitabh; J. D. Mulder and R. van Liere
Haptic display with force feedback is often necessary in several virtual environments. To enable haptic rendering of large datasets we introduce Continuously-Adaptive Haptic Rendering, a novel approach to reduce the complexity of the rendered dataset. We construct a continuous, multiresolution hierarchy of the model during the pre-processing and then at run time we use high-detail representation for regions around the probe pointer and coarser representation farther away. We achieve this by using a bell-shaped filter centered at the position of the probe pointer. Using our algorithm we are able to haptically render one to two orders of magnitude larger datasets than otherwise possible. Our approach is orthogonal to the previous work done in accelerating haptic rendering and thus can be used with them.
Interacting with Simulation Data in an Immersive Environment
(The Eurographics Association, 2000) Knöpfle, Christian; J. D. Mulder and R. van Liere
In today's automotive industry there is an increasing demand for VR technology, because it provides the possibility to switch from cost and time intensiv physical mock up's (PMU) to digital mock up's (DMU). Furthermore the visualization and examination of simulation results is a very important aspect during the whole development cycle. Therefore tools are needed, which enable the users to work with DMU's, as well as simulation data sets in an efficient and intuitive way. In this paper we present the design of a VR user interface for evaluating simulation data sets. The design of the user interface is based on the basic interaction tasks (BIT's), introduced by Foley et. al.. This allows to generalize the results presented herein and to apply them to other domains.
Time Critical Computing and Rendering of Molecular Surfaces Using a Zonal Map
(The Eurographics Association, 2000) Huitema, Henk; Liere, Robert van; J. D. Mulder and R. van Liere
We describe the zonal map, a data structure used for the visualization of large, time dependent molecular configurations in virtual environments. The governing idea of the zonal map is to use the user s line of sight to define a region of interest onto which time critical algorithms can be applied. Two examples of time critical algorithms are given: for computing and rendering of solvent-accessible surfaces of protein molecules. We show that substantial performance gains can be obtained by using the zonal map.
The Effects of Group Collaboration on Presence in a Collaborative Virtual Environment
(The Eurographics Association, 2000) Casanueva, Juan; Blake, Edwin; J. D. Mulder and R. van Liere
Presence in Collaborative Virtual Environments (CVEs) can be classified into personal presence and co-presence. Personal presence is having a feeling of being there in the CVE yourself. Co-presence is having a feeling that one is in the same place as the other participants, and that one is collaborating with real people. In this paper we describe an experiment used to investigate the effects that small group collaboration and interaction have on personal presence and copresence in a CVE. We hypothesise that collaboration and interaction enhances co-presence in a CVE. We found that there was a large difference in co-presence between two CVEs which produced different levels of collaboration and interaction. These two VEs were identical and only the task differed. This produced different levels of collaboration and interaction between the two VEs. Personal presence was measured subjectively, using a questionnaire developed by Slater et al. We have developed a co-presence questionnaire which assesses the levels of co-presence subjectively. A collaboration questionnaire has also been developed.
ERGONAUT: A Tool for Ergonomic Analyses in Virtual Environments
(The Eurographics Association, 2000) Deisinger, Joachim; Breining, Ralf; Rößler, Andreas; J. D. Mulder and R. van Liere
Ergonomic quality is becoming a crucial criterium for the success of many products. The problem of increasing the speed of product development cycles while keeping costs to a minimum could be solved by the possibility of the early evaluation of drafts regarding their ergonomic design. A digital platform is a prerequisite for the analysis of virtual prototypes. The analysis tool ERGONAUT not only fulfills this task in a Virtual Environment (VE) but also makes it possible to combine virtual and real data in a mixed mock-up. This implies that the designer is able to consider the ergonomic point of view at an early stage in the design process. In this context, a project together with the John Deere Company in Mannheim, Germany has been carried out using such an analysis tool in a pilot project. Within this first semi-productive industrial project ERGONAUT has shown its usefulness. It will help companies gain and maintain a long-term leading position in the field of ergonomics and facilitate the integration of VEs in their product development. This paper describes the anthropometric basis for ERGONAUT, its structure and functionality, the different levels of use, the system (User Interface, VE system, etc.) and some experience of the use of ERGONAUT.
Interaction Between Real and Virtual Humans: Playing Checkers
(The Eurographics Association, 2000) Torre, Rémy; Fua, Pascal; Balcisoy, Selim; Ponder, Michal; Thalmann, Daniel; J. D. Mulder and R. van Liere
For some years, we have been able to integrate virtual hu- mans into virtual environments. As the demand for Augmented Reality systems grows, so will the need for these synthetic humans to coexist and interact with humans who live in the real world. In this paper, we use the example of a checkers game between a real and a virtual human to demonstrate the integration of techniques required to achieve a realistic- looking interaction in real-time. We do not use cumbersome devices such as a magnetic motion capture system. Instead, we rely on purely image- based techniques to address the registration issue, when the camera or the objects move, and to drive the virtual human's behavior.
Dynamics in Interaction on the Responsive Workbench
(The Eurographics Association, 2000) Koutek, Michal; Post, Frits H.; J. D. Mulder and R. van Liere
In this paper we present a different view of user interaction with virtual worlds. We start from the question: how can we bring more natural object behavior into virtual environments? Currently, objects in VR applications often behave in a very un-natural way. Incorporation of physical laws in the virtual environment, together with monitoring natural user actions and behavior is desirable.We present some principles of physically more realistic behavior of virtual objects and a set of user input techniques suitable for semi-immersive VR devices such as the Responsive Workbench. We introduce springs as a new tool for assisting direct manipulation of objects in VEs.
Virtual Planetarium in CyberStage
(The Eurographics Association, 2000) Burkin, Valery; Göbel, Martin; Hasenbrink, Frank; Klimenko, Stanislav; Nikitin, Igor; Tramberend, Henrik; J. D. Mulder and R. van Liere
We describe an educational application in virtual environment, intended for teaching and demonstration of basics of astronomy. The application includes 3D models of 30 objects in the Solar System, 3200 nearby stars, a large database, containing textual descriptions of all objects in a scene, interactive map of constellations and tools for search and navigation. The methods, needed for visualization of different scale astronomical objects in virtual environment, are described.
A Volumetric Virtual Environment for Catheter Insertion Simulation
(The Eurographics Association, 2000) Zorcolo, Antonio; Gobbetti, Enrico; Zanetti, Gianluigi; Tuveri, Massimiliano; J. D. Mulder and R. van Liere
We present an experimental catheter insertion simulation system that provides users co-registered haptic and head-tracked stereoscopic visual feedback. The system works on patient-specific volumetric data acquired using standard medical imaging modalities. The actual needle insertion operation is simulated for individual patients, rather than being an example of a model surgical procedure on standard anatomy. Patient specific features may thus be studied in detail by the trainees, overcoming one of the major limitations of current training techniques.
Dextrous VR in Professional Settings: the Importance of Stereoscopic Display and Hand-Image Collocation
(The Eurographics Association, 2000) Waterworth, John; J. D. Mulder and R. van Liere
Virtual reality (VR) is becoming increasingly important in a variety of professional settings. Our particular interest is in applications requiring the examination and manipulation of detailed, volumetric medical images by surgeons and other medical staff. It is important to determine how best to maximise accuracy and speed of interaction without unrealistic technical or financial requirements. In this study, we compared performance on a trial task in a virtual environment, with and without stereoscopic display and with and without hand-image collocation. These are the most immediately tractable approaches to enhancing dexterity. Although both factors affected speed and accuracy of task completion, adding stereoscopy to desktop VR gave significantly greater benefits than adding hand-image collocation. Surprisingly, there was no additional benefit from combining the two. The work contributes to a better understanding of the factors that are important to the successful proliferation of dextrous VR in professional work settings.
Evaluation of Rotation Correction Techniques for Electromagnetic Position Tracking Systems
(The Eurographics Association, 2000) Kindratenko, Volodymyr; Bennett, Angela; J. D. Mulder and R. van Liere
Electromagnetic position tracking devices are an integral part of many modern virtual reality systems. However, they have an inherent accuracy problem due to the dependence on the local electromagnetic field that can be easily distorted by a presence of magnetically active elements near the tracker s transmitter or receiver. Several analytical techniques have been proposed to overcome this limitation, however none of them is particularly good with the correction of rotation. In this work, we investigate various rotation correction algorithms in an attempt to identify the one that is most accurate and reliable.

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