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Has files: true × Start date: 1995 × End date: 1999 ×

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Now showing 1 - 10 of 686
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    intsys96
    (1996)
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    Modelling and Rendering Graphics Scenes Composed of Multiple Volumetric Datasets
    (Blackwell Publishers Ltd and the Eurographics Association, 1999) Leu, Adrian; Chen, Min
    This paper presents a method for modelling graphics scenes consisting of multiple volumetric objects. A two-level hierarchical representation is employed, which enables the reduction of the overall storage consumption as well as rendering time. With this approach, different objects can be derived from the same volumetric dataset, and 2D images can be trivially integrated into a scene. The paper also describes an efficient algorithm for rendering such scenes on ordinary workstations, and addresses issues concerning memory requirements and disk swapping.
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    A Graph-Based Approach to Surface Reconstruction
    (Blackwell Science Ltd and the Eurographics Association, 1995) Mencl, Robert
    A new approach to the reconstruction of a surface from an unorganized set of points in space is presented. The point set may for example be obtained with a laser scanner or a manual digitizing tool, and is the only source of information about the shape of the acquired object. The basic idea is to calculate the Euclidean minimum spanning tree (EMST) of the given points. The EMST is then augmented to the so-called surface description graph (SDG). Finally the wire frame defined by the SDG are filled with triangles. The advantage of our approach is that also highly non-convex and even disconnected surfaces are reconstructed quite reliably. This is demonstrated for a variety of data sets.
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    Extending Graphics Hardware For Occlusion Queries In OpenGL
    (The Eurographics Association, 1998) Bartz, Dirk; Meißner, Michael; Hüttner, Tobias; S. N. Spencer
    For interactive rendering of large polygonal objects, fast visibility queries are necessary to quickly decide whether polygonal objects are visible and need to be rendered. None of the numerous published algorithms provide visibility performance for interactive rendering of large models. In this paper, we propose an OpenGL extension for fast occlusion queries. Added after the depth test stage of the OpenGL rendering pipeline. our algorithm provides fast queries to establish the occlusion of polygonal objects. Furthermore, hardware aspects of this proposal are discussed and possible implementations on two different graphics architectures are presented.
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    ve99
    (1999)
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    Network Services
    (Blackwell Publishers Ltd and the Eurographics Association, 1997)
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    Virtual Dunhuang Art Cave: A Cave within a CAVE
    (Blackwell Publishers Ltd and the Eurographics Association, 1999) Lutz, B.; Weintke, M.
    Virtual Reality can present historical places in a three-dimensional and interactive way, giving visitors a photorealistic impression of objects. Not only existing scenarios can be shown, but VR can also be used to rebuild scenarios that were damaged or destroyed a long time ago, giving new life to the cultural heritage. We used Virtual Reality to present the Mogao Grottos in Dunhuang. This cave site is one of the most important cultural and religious places by the ancient Silk Road. The presentation is to give visitors the impression of visiting the cave site and provide information about the caves, paintings and statues in an interesting way. To achieve this, we developed a new, intuitive interaction paradigm, which enables the user to explore the caves. To give observers a photorealistic impression of the caves and to create a feeling of immersion, innovative rendering techniques were integrated.The resulting presentation combines Virtual Reality and archaeology to give tourists a realistic experience of this cave site and to support scientists in their research work.
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    WebTalk: a 3D collaborative environment to access the Web
    (Eurographics Association, 1999) Paolini, P.; Barbieri, T.; Loiudice, P.; Alonzo, F.; Arru, M.; Zanti, M.; Gaia, G.
    The notion of cooperative visit and interaction within a web site, both at 2D and 3D level, could add decisive motivation to pursue exploitation of the third dimension in networked environments. A prototype developed at the HOC laboratory in Politecnico of Milan, WEBTALK, allows development of custom 3D environments in which actions and situations can be shared throughout a network. The current prototype makes use of standard web-based Internet/Intranet technology: it is composed of a VRML (Virtual Reality Modeling Language) graphical engine and a Java-based TCP/IP (the Internet Protocol) communication layer. The technique has proven itself successful and has given rise to several interesting applications, such as the creation of Virtual 3D Museum Spaces at the National Science Museum (www.museoscienza.org), in which visitors can visit the museum interacting with the exhibits themselves and sharing their experiences with other visitors - even joining a guided tour with the virtual museum guide. A new prototype will make use of a completely Java-based environment, using Sun’s Java 2 and Java 3D. The new WEBTALK will stress even further the issues of third party external authoring of virtual worlds and of cooperation patterns within the shared environments, with a distinction between shared object geometries, shared object behaviors, shared object data (stored in an on-line DBMS), and cooperation metaphors within the virtual world. Linking to 2D-based web sites resources will lead cooperation patterns to be extended also to regular web-space.
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    TAYRA - A 3D Graphics Raster Processor
    (The Eurographics Association, 1996) Waller, Marcus; Dunnett, Graham; Bassett, Mike; MCCann, Shaun; Makris, Alex; White, Martin; Lister, Paul; Bengt-Olaf Schneider and Andreas Schilling
    This paper describes the Junctionality oj a 3D Graphics Raster Processor called TAYRA. TAYRA consists in the most part oj Graphics Raster Pipeline with five major external interfaces: PCI Master/Target, Depth, Texture, Colour and Video Interfaces.The Graphics Raster Pipeline perform'S' all the major OpenGL style (not necessarily compliant) raster functions: scan conversion; lines, spans, triangles, rectangles, perspective correction o f texture coordinates. mip map jevel selection, and many other texture modes, alpha blending, and other Junctionalities. Further, through TAYRA's fast host to buffer access mechanisms it can do advanced stencilling, multi-pass antialiasing, and other algorithms; all accelerated in hardware with a sustained pixel write speed of 29 MPixels/sec (peak of 33 MPixels/sec). This translates to a peak 25 pixel triangle drawing speed of 890K Triangles/sec, limited bv PCI bus bandwidth.
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    Improved Laplacian Smoothing of Noisy Surface Meshes
    (Blackwell Publishers Ltd and the Eurographics Association, 1999) Vollmer, J.; Mencl, R.; Muller, H.
    This paper presents a technique for smoothing polygonal surface meshes that avoids the well-known problem of deformation and shrinkage caused by many smoothing methods, like e.g. the Laplacian algorithm. The basic idea is to push the vertices of the smoothed mesh back towards their previous locations. This technique can be also used in order to smooth unstructured point sets, by reconstructing a surface mesh to which the smoothing technique is applied. The key observation is that a surface mesh which is not necessarily topologically correct, but which can efficiently be reconstructed, is sufficient for that purpose.