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Now showing 1 - 10 of 15
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    Realistic Water Volumes in Real-Time
    (The Eurographics Association, 2006) Baboud, Lionel; Décoret, Xavier; Norishige Chiba and Eric Galin
    We present a real-time technique to render realistic water volumes. Water volumes are represented as the space enclosed between a ground heightfield and an animable water surface heightfield. This representation allows the application of recent GPU-based heightfield rendering algorithms. Our method is a simplified raytracing approach which correctly handles reflections and refractions and allows us to render complex effects such as light absorption, refracted shadows and refracted caustics. It runs at high framerates by exploiting the power of the latest graphic cards, and could be used in real-time applications like video games, or interactive simulation.
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    Polynomial Approximation of Blinn-Phong Model
    (The Eurographics Association, 2006) Öztürk, Aydin; Bilgili, Ahmet; Kurt, Murat; Louise M. Lever and Mary McDerby
    The Phong model has been one of the oldest and the most popular reflection models in Computer Graphics. It can be used to model specular highlights of various materials. In this paper, we consider a polynomial model and obtain a linear approximation of the Blinn-Phong model. Approximation errors were obtained for the proposed model and empirical comparisons were made using a measured BRDF data set. Based on the empirical results, it is shown that proposed model provides visually convincing representation of BRDF and performs well for modeling the surface reflectance.
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    Statistical Acquisition of Texture Appearance
    (The Eurographics Association, 2006) Ngan, Addy; Durand, Frédo; Tomas Akenine-Moeller and Wolfgang Heidrich
    We propose a simple method to acquire and reconstruct material appearance with sparsely sampled data. Our technique renders elaborate view- and light-dependent effects and faithfully reproduces materials such as fabrics and knitwears. Our approach uses sparse measurements to reconstruct a full six-dimensional Bidirectional Texture Function (BTF). Our reconstruction only require input images from the top view to be registered, which is easy to achieve with a fixed camera setup. Bidirectional properties are acquired from a sparse set of viewing directions through image statistics and therefore precise registrations for these views are unnecessary. Our technique is based on multi-scale histograms of image pyramids. The full BTF is generated by matching the corresponding pyramid histograms to interpolated top-view images.We show that the use of multi-scale image statistics achieves a visually plausible appearance. However, our technique does not fully capture sharp specularities or the geometric aspects of parallax. Nonetheless, a large class of materials can be reproduced well with our technique, and our statistical characterization enables acquisition of such materials efficiently using a simple setup.
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    Perception-based Lighting Design
    (The Eurographics Association, 2006) Ha, Hai Nam; Olivier, Patrick; Louise M. Lever and Mary McDerby
    Perception-based lighting design approaches model image quality using a cognitively grounded objective function which is in turn optimised through manipulation of the lighting parameters of a scene. We present, and demonstrate, a detailed implementation of perception-based lighting design, including the application and evaluation of stochastic optimisation using genetic algorithms.
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    Perceived Rendering Thresholds for High-Fidelity Graphics on Small Screen Devices
    (The Eurographics Association, 2006) Aranha, M.; Debattista, K.; Chalmers, A.; Hill, S.; Louise M. Lever and Mary McDerby
    Small screen devices, also known as small-form-factor (SFF) devices including mobile phones and ultra mobile PCs are increasingly ubiquitous. Their uses includes gaming, navigation and interactive visualisation. SFF devices are, however, inherently limited by their physical characteristics for perception as well as limited processing and battery power. High-fidelity graphic systems have significant computational requirements which can be reduced through use of perceptually-based rendering techniques. In order to exploit these techniques on SFF devices a sound understanding of the perceptual characteristics of the display device is needed. This paper investigates the perceived rendering threshold specific for SFF devices in comparison to traditional display devices. We show that the threshold for SFF systems differs significantly from typical displays indicating substantial savings in rendering quality and thus computational resources can be achieved for SFF devices.
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    Simulating Caustics due to Liquid-Solid Interface Menisci
    (The Eurographics Association, 2006) Bourque, Eric; Dufort, Jean-François; Laprade, Michelle; Poulin, Pierre; Norishige Chiba and Eric Galin
    A solid partially immersed in a liquid creates a local deformation of the liquid surface at their interface. This deformation, called a meniscus, exhibits high curvature, and as such, produces very intriguing caustic patterns. However, this natural phenomena has been neglected in almost all previous liquid simulation techniques. We propose a complete solution to model and render meniscal illumination effects. First, we outline a physicallymotivated approach to approximating the geometry of the meniscus. We then describe the targeted photon map, an adapted photon map which facilitates efficient sampling of the finely tessellated menisci. This technique, which integrates well within traditional photon mapping, allows for automatically rendering illumination effects for complex solid-liquid interfaces. Several images rendered using this technique are presented and are compared to their real-world counterparts.
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    Physically Based Simulation and Visualization of Fire in Real-Time using the GPU
    (The Eurographics Association, 2006) Rødal, Samuel; Storli, Geir; Gundersen, Odd Erik; Louise M. Lever and Mary McDerby
    In this paper we present a physically based framework for real-time simulation and visualization of fire using the GPU. The physics of fire is modeled through a combination of a fluid solver and a combustion process causing the characteristic motion of fire. The simulation results are then rendered using a particle system combined with a black-body radiation model where the physically based simulation governs both the motion and appearance of the particles. By performing individual slice simulations in 2D and combining them using volumetric extrusion we achieve better performance than by performing the simulation in 3D without compromising the visual quality. Thus, achieving our goal of visualizing bonfire and torch-like fire effects with high visual quality in real-time.
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    Designing a Virtual Reality Game for the CAVE
    (The Eurographics Association, 2006) Livatino, S.; Agerbech, V.; Johansen, A.; Johansen, B.; S. Battiato and G. Gallo and F. Stanco
    Virtual Reality has for many years been a technology which has stagnated in application and software development for games. The applications available for VR environments have increased but they mostly remain related to scientific purposes while computer games in VR are still being developed and only show a part of their actual potential. The game industry has begun to see the possibilities of VR games in a near future with the implementation of some popular games to a CAVE system. However, a full immersion VR solution still remains uncommon and expensive. This paper aims to demonstrate the potential of VR games, and in particular games for the CAVE, now that affordable solutions are close to reach as more powerful hardware is available at low price. The focus is also on the methodology to be pursued while designing a VR game. Results were encouraging and tests performed on a first prototype demonstrates system feasibility.
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    Fast Rendering of Complex Dynamic Scenes
    (The Eurographics Association, 2006) Kovalcík, Vit; Sochor, Jiri; Louise M. Lever and Mary McDerby
    We present a novel algorithm capable of rendering complex dynamic scenes at high frame rates. The key part of the algorithm is occlusion culling which is performed by an optimized usage of the hardware occlusion queries. The spatial organization of the scene using 2-level BSP-like hierarchy helps to speed up evaluating full and partial occlusion of the objects. The algorithm handles both static and dynamic objects and places no restrictions on the shape of objects.
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    Wavelet Radiance Transport for Interactive Indirect Lighting
    (The Eurographics Association, 2006) Kontkanen, Janne; Turquin, Emmanuel; Holzschuch, Nicolas; Sillion, François X.; Tomas Akenine-Moeller and Wolfgang Heidrich
    Global illumination is a complex all-frequency phenomenon including subtle effects caused by indirect lighting. Computing global illumination interactively for dynamic lighting conditions has many potential applications, notably in architecture, motion pictures and computer games. It remains a challenging issue, despite the considerable amount of research work devoted to finding efficient methods. This paper presents a novel method for fast computation of indirect lighting; combined with a separate calculation of direct lighting, we provide interactive global illumination for scenes with diffuse and glossy materials, and arbitrarily distributed point light sources. To achieve this goal, we introduce three new tools: a 4D wavelet basis for concise radiance expression, an efficient hierarchical pre-computation of the Global Transport Operator representing the entire propagation of radiance in the scene in a single operation, and a run-time projection of direct lighting on to our wavelet basis. The resulting technique allows unprecedented freedom in the interactive manipulation of lighting for static scenes.