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Item Geometry Textures and Applications(The Eurographics Association and Blackwell Publishing Ltd, 2008) De Toledo, Rodrigo; Wang, Bin; Levy, BrunoGeometry textures are a novel geometric representation for surfaces based on height maps. The visualization is done through a graphics processing unit (GPU) ray casting algorithm applied to the whole object. At rendering time, the fine-scale details (mesostructures) are reconstructed preserving original quality. Visualizing surfaces with geometry textures allows a natural level-of-detail (LOD) behaviour. There are numerous applications that can benefit from the use of geometry textures. In this paper, besides a mesostructure visualization survey, we present geometry textures with three possible applications: rendering of solid models, geological surfaces visualization and surface smoothing.Item Table of Contents and Cover(The Eurographics Association and Blackwell Publishing Ltd, 2008)Item Transferring the Rig and Animations from a Character to Different Face Models(The Eurographics Association and Blackwell Publishing Ltd, 2008) Orvalho, Veronica Costa; Zacur, Ernesto; Susin, AntonioWe introduce a facial deformation system that allows artists to define and customize a facial rig and later apply the same rig to different face models. The method uses a set of landmarks that define specific facial features and deforms the rig anthropometrically. We find the correspondence of the main attributes of a source rig, transfer them to different three-demensional (3D) face models and automatically generate a sophisticated facial rig. The method is general and can be used with any type of rig configuration. We show how the landmarks, combined with other deformation methods, can adapt different influence objects (NURBS surfaces, polygon surfaces, lattice) and skeletons from a source rig to individual face models, allowing high quality geometric or physically-based animations. We describe how it is possible to deform the source facial rig, apply the same deformation parameters to different face models and obtain unique expressions. We enable reusing of existing animation scripts and show how shapes nicely mix one with the other in different face models. We describe how our method can easily be integrated in an animation pipeline. We end with the results of tests done with major film and game companies to show the strength of our proposal.Item Tangible Heritage: Production of Astrolabes on a Laser Engraver(The Eurographics Association and Blackwell Publishing Ltd, 2008) Zotti, G.The astrolabe, an analog computing device, used to be the iconic instrument of astronomers during the Middle Ages. It allowed a multitude of operations of practical astronomy which were otherwise cumbersome to perform in an epoch when mathematics had apparently almost been forgotten. Usually made from wood or sheet metal, a few hundred instruments, mostly from brass, survived until today and are valuable museum showpieces. This paper explains a procedural modelling approach for the construction of the classical kinds of astrolabes, which allows a wide variety of applications from plain explanatory illustrations to three-dimensional (3D) models, and even the production of working physical astrolabes usable for public or classroom demonstrations.Item High-speed Marching Cubes using HistoPyramids(The Eurographics Association and Blackwell Publishing Ltd, 2008) Dyken, Christopher; Ziegler, Gernot; Theobalt, Christian; Seidel, Hans-PeterWe present an implementation approach for Marching Cubes (MC) on graphics hardware for OpenGL 2.0 or comparable graphics APIs. It currently outperforms all other known graphics processing units (GPU)-based iso-surface extraction algorithms in direct rendering for sparse or large volumes, even those using the recently introduced geometry shader (GS) capabilites. To achieve this, we outfit the Histogram Pyramid (HP) algorithm, previously only used in GPU data compaction, with the capability for arbitrary data expansion. After reformulation of MC as a data compaction and expansion process, the HP algorithm becomes the core of a highly efficient and interactive MC implementation. For graphics hardware lacking GSs, such as mobile GPUs, the concept of HP data expansion is easily generalized, opening new application domains in mobile visual computing. Further, to serve recent developments, we present how the HP can be implemented in the parallel programming language CUDA (compute unified device architecture), by using a novel 1D chunk/layer construction.Item Real-Time Indirect Illumination and Soft Shadows in Dynamic Scenes Using Spherical Lights(The Eurographics Association and Blackwell Publishing Ltd, 2008) Guerrero, P.; Jeschke, S.; Wimmer, M.We present a method for rendering approximate soft shadows and diffuse indirect illumination in dynamic scenes. The proposed method approximates the original scene geometry with a set of tightly fitting spheres. In previous work, such spheres have been used to dynamically evaluate the visibility function to render soft shadows. In this paper, each sphere also acts as a low-frequency secondary light source, thereby providing diffuse one-bounce indirect illumination. The method is completely dynamic and proceeds in two passes: In a first pass, the light intensity distribution on each sphere is updated based on sample points on the corresponding object surface and converted into the spherical harmonics basis. In a second pass, this radiance information and the visibility are accumulated to shade final image pixels. The sphere approximation allows us to compute visibility and diffuse reflections of an object at interactive frame rates of over 20 fps for moderately complex scenes.Item Diffusion Based Photon Mapping(The Eurographics Association and Blackwell Publishing Ltd, 2008) Schjoeth, L.; Sporring, J.; Fogh Olsen, O.Density estimation employed in multi-pass global illumination algorithms give cause to a trade-off problem between bias and noise. The problem is seen most evident as blurring of strong illumination features. In particular, this blurring erodes fine structures and sharp lines prominent in caustics. To address this problem, we introduce a photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way, we preserve important illumination features, while eliminating noise. We demonstrate the applicability of our algorithm through a series of tests. In the tests, we evaluate the visual and computational performance of our algorithm comparing it to existing popular algorithms.Item Book Review(The Eurographics Association and Blackwell Publishing Ltd, 2008)Item Camera Control in Computer Graphics(The Eurographics Association and Blackwell Publishing Ltd, 2008) Christie, Marc; Olivier, Patrick; Normand, Jean-MarieRecent progress in modelling, animation and rendering means that rich, high fidelity virtual worlds are found in many interactive graphics applications. However, the viewer s experience of a 3D world is dependent on the nature of the virtual cinematography, in particular, the camera position, orientation and motion in relation to the elements of the scene and the action. Camera control encompasses viewpoint computation, motion planning and editing. We present a range of computer graphics applications and draw on insights from cinematographic practice in identifying their different requirements with regard to camera control. The nature of the camera control problem varies depending on these requirements, which range from augmented manual control (semi-automatic) in interactive applications, to fully automated approaches. We review the full range of solution techniques from constraint-based to optimization-based approaches, and conclude with an examination of occlusion management and expressiveness in the context of declarative approaches to camera control.Item 2008 Eurographics Symposium on Parallel Graphics and Visualization(The Eurographics Association and Blackwell Publishing Ltd, 2008) Weiskopf, Daniel