Issue 4

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https://diglib.eg.org/handle/10.2312/107

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    Towards Interactive Real-Time Crowd Behavior Simulation
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Ulicny, Branislav; Thalmann, Daniel
    While virtual crowds are becoming common in non-real-time applications, the real-time domain is still relativelyunexplored. In this paper we discuss the challenges involved in creating such simulations, especially the needto efficiently manage variety. We introduce the concept of levels of variety. Then we present our work oncrowd behaviour simulation aimed at interactive real-time applications such as computer games or virtualenvironments. We define a modular behavioural architecture of a multi-agent system allowing autonomous andscripted behaviour of agents supporting variety. Finally we show applications of our system in a virtual realitytraining system and a virtual heritage reconstruction.ACM CSS: I.3.7 Three-Dimensional Graphics and Realism-Animation, I.2.11 Distributed ArtificialIntelligence-Multi-agent systems
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    Eurographics Italy 1st Conference
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Bordegoni, Monica
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    Vortex Tracking and Visualisation in a Flow Past a Tapered Cylinder
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Reinders, Freek; Sadarjoen, I. Ari; Vrolijk, Benjamin; Post, Frits H.
    In this paper we explore a novel combined application of two of our existing visualisation techniques to thetracking of 3D vortex tubes in an unsteady flow. The applied techniques are the winding-angle vortex extractiontechnique based on streamline geometry, and the attribute-based feature tracking technique. We have applied theseto the well-known case of an unsteady 3D flow past a tapered cylinder.First, 2D vortices are detected in a number of horizontal slices for each time step, by means of the winding-anglevortex extraction method. For each 2D vortex a number of attributes are calculated and stored. These vorticesare visualised by a special type of ellipse icons, showing the position, shape and rotational direction and speed ineach slice.Next, for each time step, 3D vortex tubes are constructed from the 2D vortices by applying the feature trackingprocedure in a spatial dimension to connect the corresponding vortices in adjacent slices. The result is a graphattribute set with the 2D vortex attributes in the nodes and the spatial correspondences as edges.Finally, the 3D vortex tubes are tracked in time using the same tracking procedure, for finding the correspondingtubes in successive time steps. The result is a description of the evolution of the 3D vortices. An interactive, time-dependentvisualisation is generated using the temporal correspondences of each vortex tube. This analysis revealsa number of interesting patterns.ACM CSS: I.3.8 Computer Graphics-Applications
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    13th Eurographics Workshop on Rendering
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Debevec, Paul; Gibson, Simon
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    Report of the Statutory Auditors to the General Meeting of the Members of Eurographics Association Geneva
    (Blackwell Publishers, Inc and the Eurographics Association, 2002)
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    23rd Eurographics General Assembly
    (Blackwell Publishers, Inc and the Eurographics Association, 2002)
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    A Spoken Dialogue System for Navigation in Non-Immersive Virtual Environments
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) McNeill, M.D.J.; Sayers, H.; Wilson, S.; Mc Kevitt, P.
    Navigation is the process by which people control their movement in virtual environments and is a corefunctional requirement for all virtual environment (VE) applications. Users require the ability to move, controllingorientation, direction of movement and speed, in order to achieve a particular goal within a VE. Navigation israrely the end point in itself (which is typically interaction with the visual representations of data) but applicationsoften place a high demand on navigation skills, which in turn means that a high level of support for navigationis required from the application. On desktop systems navigation in non-immersive systems is usually supportedthrough the usual hardware devices of mouse and keyboard. Previous work by the authors shows that many usersexperience frustration when trying to perform even simple navigation tasks - users complain about getting lost,becoming disorientated and finding the interface 'difficult to use'. In this paper we report on work in progressin exploiting natural language processing (NLP) technology to support navigation in non-immersive virtualenvironments. A multi-modal system has been developed which supports a range of high-level (spoken) navigationcommands and indications are that spoken dialogue interaction is an effective alternative to mouse and keyboardinteraction for many tasks. We conclude that multi-modal interaction, combining technologies such as NLP withmouse and keyboard may offer the most effective interaction with VEs and identify a number of areas where furtherwork is necessary.ACM CSS: I.3.6 Computer Graphics Methodology and Techniques-Interaction and Techniques, I.3.7 Three-DimensionalGraphics and Realism-Virtual Reality, I.2.7 Natural Language Processing-Speech Recognitionand Synthesis
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    Synthetic Vision and Memory for Autonomous Virtual Humans
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Peters, C.; O'Sullivan, C.
    A memory model based on 'stage theory', an influential concept of memory from the field of cognitive psychology,is presented for application to autonomous virtual humans. The virtual human senses external stimuli througha synthetic vision system. The vision system incorporates multiple modes of vision in order to accommodate aperceptual attention approach. The memory model is used to store perceived and attended object information atdifferent stages in a filtering process. The methods outlined in this paper have applications in any area wheresimulation-based agents are used: training, entertainment, ergonomics and military simulations to name but afew.ACM CSS: I. 3.7 Computer Graphics-Virtual reality
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    1st Ibero-American Symposium in Computer Graphics
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Marcos, Aderito; Brunet, Pere; Jorge, Joaquim; Regincos, Jordi
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    Author Index Volume 21 (2002)
    (Blackwell Publishers, Inc and the Eurographics Association, 2002)
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    Erratum: Artistic Surface Rendering Using Layout of Text
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Surazhsky, Tatiana; Elber, Gershon
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    Feature Model Visualization
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Bronsvoort, Willem F.; Bidarra, Rafael; Noort, Alex
    Feature modelling is now the predominant way of modelling products. Feature visualization is an important aspect here that can still be considerably improved. In this paper, an integrated way of visualizing feature models is presented, using new techniques for both the geometry and the structure of models. For the geometry of feature models, techniques are presented to visualize a selected subset of form features in a way that clearly distinguishes them from the rest of the model, as well as functional information such as closure faces of subtractive form features. For the structure of features models, techniques are presented to visualize several types of graphs. The different visualization techniques are used in an integrated way. Implementation of some of the techniques requires a non-manifold representation of the geometry of the feature model. This representation, and some other implementation aspects, are briefly described. Throughout the paper, numerous examples of images of feature models are given which show that the new visualization techniques can indeed improve the effectiveness of feature modelling.ACM CSS: I.3.7 Three-Dimensional Graphics and Realism-visible line/surface algorithms, J.6 Computer-AidedEngineering-feature modelling
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    Visualizing Crowds in Real-Time
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Tecchia, Franco; Loscos, Celine; Chrysanthou, Yiorgos
    Real-time crowd visualization has recently attracted quite an interest from the graphics community and, asinteractive applications become even more complex, there is a natural demand for new and unexplored applicationscenarios. However, the interactive simulation of complex environments populated by large numbers of virtualcharacters is a composite problem which poses serious difficulties even on modern computer hardware. In thispaper we look at methods to deal with various aspects of crowd visualization, ranging from collision detectionand behaviour modeling to fast rendering with shadows and quality shading. These methods make extensive useof current graphics hardware capabilities with the aim of providing scalability without compromising run-timespeed. Results from a system employing these techniques seem to suggest that simulations of reasonably complexenvironments populated with thousands of animated characters are possible in real-time.ACM CSS: I.3.7 Three-Dimensional Graphics and Realism-Animation
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    Hierarchical Impostors for the Flocking Algorithm in 3D
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) O'Hara, Noel
    The availability of powerful and affordable 3D PC graphics boards has made the rendering of rich immersiveenvironments possible at interactive speeds. The scene update rate and the appropriate behaviour of objects withinthe world are central to this immersive feeling. This paper is concerned with the behaviour computations involvedin the flocking algorithm, which has been used extensively to emulate the flocking behaviour of creatures found innature. The main contribution of this paper is a new method for hierarchically combining portions of the flocksinto groups to reduce the cost of the behavioural computation, allowing far larger flocks to be updated in real-timein the world.ACM CSS: I.3.7 Three-Dimensional Graphics and Realism-Animation
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    Levels of Detail for Crowds and Groups
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) O'Sullivan, C.; Cassell, J.; Vilhjalmsson, H.; Dingliana, J.; Dobbyn, S.; McNamee, B. and Peters, C. and Giang, T.
    Work on levels of detail for human simulation has occurred mainly on a geometrical level, either by reducing the numbers of polygons representing a virtual human, or replacing them with a two-dimensional imposter. Approaches that reduce the complexity of motions generated have also been proposed. In this paper, we describe ongoing development of a framework for Adaptive Level Of Detail for Human Animation (ALOHA), which incorporates levels of detail for not only geometry and motion, but also includes a complexity gradient for natural behaviour, both conversational and social.ACM CSS: I.3.7 Three-Dimensional Graphics and Realism-Animation
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    Siggraph 2002
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Laycock, Stephen D.; Laycock, Robert G.
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    Adaptive Zooming in Web Cartography
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Cecconi, Alesandro; Galanda, Martin
    Beyond any doubt much of the current web mapping and web GIS applications lack cartographic quality. Thereasons aren't only the technical limitations related to Internet delivery, but also the neglect of one of the maincartographic principles of digital mapping, namely adaptive zooming. Adaptive zooming describes the adjustmentof a map, its contents and the symbolization to target scale in consequence of a zooming operation. The approachdescribed in this paper proposes the combination of two commonly known concepts: on the one hand levelsof detail (LoD) for those object classes, that require high computational cost for the automated generalizationprocess (e.g. buildings, road network); on the other hand an on-the-fly generalization for those object classeswhich can be generalized by less complex methods and algorithms (e.g. rivers, lakes). Realizing such interactiveand dynamic concept for web mapping requires the use of vector based visualization tools. The data format bestmeeting the criteria is the W3C standard Scalable Vector Graphics (SVG). Thus, it has been used to implementthe presented ideas in a prototype application for topographic web mapping based on the landscape modelVECTOR25 of the Swiss Federal Office of Topography.
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    Join Now!
    (Blackwell Publishers, Inc and the Eurographics Association, 2002)
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    Eurographics Spain 11th Conference
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) Isern, Jordi Regincos
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    Eurographics Ireland 2002 Workshop
    (Blackwell Publishers, Inc and the Eurographics Association, 2002) O'Sullivan, Carol