26-Issue 4
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Item 28th EUROGRAPHICS General Assembly(The Eurographics Association and Blackwell Publishing Ltd, 2007)Item CGF Reviewers(The Eurographics Association and Blackwell Publishing Ltd, 2007)Item Data-driven Tetrahedral Mesh Subdivision(The Eurographics Association and Blackwell Publishing Ltd, 2007) Rodriguez, L.; Navazo, I.; Vinacua, A.Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to reduce the discrepancy between interpolated values based on either scheme at arbitrary locations. An advantage of the method presented is that it requires few subdivisions and all decisions are made locally at each tetrahedron. We discuss the algorithm s performance and applications.Item Digital Mosaic Frameworks - An Overview(The Eurographics Association and Blackwell Publishing Ltd, 2007) Battiato, S.; Di Blasi, G.; Farinella, G. M.; Gallo, G.Art often provides valuable hints for technological innovations especially in the field of Image Processing and Computer Graphics. In this paper we survey in a unified framework several methods to transform raster input images into good quality mosaics. For each of the major different approaches in literature the paper reports a short description and a discussion of the most relevant issues. To complete the survey comparisons among the different techniques both in terms of visual quality and computational complexity are provided.Item Distance-Ranked Connectivity Compression of Triangle Meshes(The Eurographics Association and Blackwell Publishing Ltd, 2007) Marais, P.; Gain, J.; Shreiner, D.We present a new, single-rate method for compressing the connectivity information of a connected 2-manifold triangle mesh with or without boundary. Traditional compression schemes interleave geometry and connectivity coding, and are thus typically unable to utilize information from vertices (mesh regions) they have not yet processed. With the advent of competitive point cloud compression schemes, it has become feasible to develop separate connectivity encoding schemes that can exploit complete, global vertex position information to improve performance.Our scheme demonstrates the utility of this separation of vertex and connectivity coding. By traversing the mesh edges in a consistent fashion, and using global vertex information, we can predict the position of the vertex that completes the unprocessed triangle attached to a given edge. We then rank the vertices in the neighborhood of this predicted position by their Euclidean distance. The distance rank of the correct closing vertex is stored. Typically, these rank values are small, and the set of rank values thus possesses low entropy and compresses very well. The sequence of rank values is all that is required to represent the mesh connectivity-no special split or merge codes are necessary.Results indicate improvements over traditional valence-based schemes for more regular triangulations. Highly irregular triangulations or those containing a large number of slivers are not well modelled by our current set of predictors and may yield poorer connectivity compression rates than those provided by the best valence-based schemes.Item Editorial(The Eurographics Association and Blackwell Publishing Ltd, 2007) Duke, David; Scopigno, RobertoItem Erratum(The Eurographics Association and Blackwell Publishing Ltd, 2007) Langdon, W. B.Item Erratum(The Eurographics Association and Blackwell Publishing Ltd, 2007)Item Expeditious Modelling of Virtual Urban Environments with Geospatial L-systems(The Eurographics Association and Blackwell Publishing Ltd, 2007) Coelho, A.; Bessa, M.; Sousa, A. Augusto; Ferreira, F. NunesL-systems have been used in Computer Graphics, namely for modelling plants, as well as in a few experiments to model urban environments. However, the lack of geospatial awareness is a limitation and in spite of some developments like open L-systems, that introduced the ability to communicate with the environment, there was a need for more flexibility. This paper presents Geospatial L-systems, a new extension of L-systems that incorporates geospatial awareness, and shows an application in the area of expeditious modelling of urban environments. A modelling system, named XL3D, generates virtual urban environments automatically from a XML based document that contains a modelling specification and accesses data sources in an interoperable way. The integration of geospatial L-systems in this modelling system has increased the potential for automation and the potential to generate virtual urban environments with a higher level of detail and visual fidelity, with a lower level of complexity of the modelling processes. These facts are shown in a case study where a virtual urban environment, taken from an area in the Porto downtown, is generated by this solution.Item Graphics-Based Learning in First-Year Computer Science(The Eurographics Association and Blackwell Publishing Ltd, 2007) Davis, T. A.This paper proposes a method for teaching a first-year course in computer science using graphics-based problems as the teaching medium. Specifically, we present a method for instruction in programming using a semester-long project of developing a ray tracer. This effort is part of a larger project, known as, in which a broad range of undergraduate courses are taught using computer graphics as the motivating application. An overview of this project is provided, along with description and results from the first trial CS2 course instructed using this technique.Item Index(The Eurographics Association and Blackwell Publishing Ltd, 2007)Item The John Lansdown Award 2007(The Eurographics Association and Blackwell Publishing Ltd, 2007) Duce, DavidItem Manipulating, Deforming and Animating Sampled Object Representations(The Eurographics Association and Blackwell Publishing Ltd, 2007) Chen, M.; Correa, C.; Islam, S.; Jones, M. W.; Shen, P.-Y.; Silver, D.; Walton, S. J. and Willis, P. J.A sampled object representation (SOR) defines a graphical model using data obtained from a sampling process, which takes a collection of samples at discrete positions in space in order to capture certain geometrical and physical properties of one or more objects of interest. Examples of SORs include images, videos, volume datasets and point datasets. Unlike many commonly used data representations in computer graphics, SORs lack in geometrical, topological and semantic information, which is much needed for controlling deformation and animation. Hence it poses a significant scientific and technical challenge to develop deformation and animation methods that operate upon SORs. Such methods can enable computer graphics and computer animation to benefit enormously from the advances of digital imaging technology.In this state of the art report, we survey a wide range of techniques that have been developed for manipulating, deforming and animating SORs. We consider a collection of elementary operations for manipulating SORs, which can serve as building blocks of deformation and animation techniques. We examine a collection of techniques that are designed to transform the geometry shape of deformable objects in sampled representations and pay particular attention to their deployment in surgical simulation. We review a collection of techniques for animating digital characters in SORs, focusing on recent developments in volume animation.Item New EUROGRAPHICS Fellows(The Eurographics Association and Blackwell Publishing Ltd, 2007)Item Outstanding Technical Contributions Award 2007(The Eurographics Association and Blackwell Publishing Ltd, 2007) Drettakis, GeorgeItem Rendering Plasma Phenomena: Applications and Challenges(The Eurographics Association and Blackwell Publishing Ltd, 2007) Baranoski, G.V.G.; Rokne, J.G.Plasmas are ubiquitous in the Universe. An understanding of plasma phenomena is therefore of importance in almost every area of astrophysics, from stellar atmospheres to star clusters. Plasmas also occur in daily life both in industrial processes and in consumer products. Recent groundbreaking data is making this the golden age of plasma science. Although direct observations and analysis of data provide important physical evidence for plasma phenomena, they do not necessarily explain the phenomena. Hence, recent discoveries in this area might not only arise out of observations, but also from visual simulations of the phenomena supported by advanced rendering technologies. This report describes the state of art of such simulations, and examines practical issues often overlooked in the literature. Educational and public outreach applications are also discussed. Although the emphasis is on the predictive rendering of plasma processes, the simulation guidelines and trade-offs addressed in this report can be extended to other types of natural phenomena. The report closes with a discussion of further avenues of research involving the visual simulation of plasma phenomena.Item REPORT OF THE STATUTORY AUDITORS TO THE GENERAL MEETING OF THE MEMBERS OF EUROGRAPHICS ASSOCIATION GENEVA(The Eurographics Association and Blackwell Publishing Ltd, 2007)Item ShaderX by Wolfgang Engel(The Eurographics Association and Blackwell Publishing Ltd, 2007) Callieri, M.Item Teaching, Exploring, Learning-Developing Tutorials for In-Class Teaching and Self-Learning(The Eurographics Association and Blackwell Publishing Ltd, 2007) Beckhaus, S.; Blom, K. J.This paper presents an experience report on a novel approach for a course on intermediate and advanced computer graphics topics. The approach uses Teachlet Tutorials, a combination of traditional seminar-type teaching with interactive exploration of the content by the audience, plus development of self-contained tutorials on the topic. In addition to a presentation, an interactive software tool is developed by the students to assist the audience in learning and exploring the topic s details. This process is guided through set tasks. The resulting course material is developed for two different contexts: (a) for classroom presentation and (b) as an interactive, self-contained, self-learning tutorial. The overall approach results in a more thorough understanding of the topic both for the student teachers as well as for the class participants. In addition to detailing the Teachlet Tutorial approach, this paper presents our experiences implementing the approach in our Advanced Computer Graphics course and presents the resultant projects. Most of the final Teachlet Tutorials were surprisingly good and we had excellent feedback from the students on the approach and course.Item Young Researcher Award 2007(The Eurographics Association and Blackwell Publishing Ltd, 2007) Kautz, Jan