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912
ArtDefo  Accurate Real Time Deformable Objects
, 1999
"... We present an algorithm for fast, physically accurate simulation of deformable objects suitable for real time animation and virtual environment interaction. We describe the boundary integral equation formulation of static linear elasticity as well as the related Boundary Element Method (BEM) discret ..."
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Cited by 217 (17 self)
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We present an algorithm for fast, physically accurate simulation of deformable objects suitable for real time animation and virtual environment interaction. We describe the boundary integral equation formulation of static linear elasticity as well as the related Boundary Element Method (BEM) discretization technique. In addition, we show how to exploit the coherence of typical interactions to achieve low latency; the boundary formulation lends itself well to a fast update method when a few boundary conditions change. The algorithms are described in detail with examples from ArtDefo, our implementation.
Metropolis Light Transport
 Computer Graphics (SIGGRAPH '97 Proceedings
, 1997
"... We present a new Monte Carlo method for solving the light transport problem, inspired by the Metropolis sampling method in computational physics. To render an image, we generate a sequence of light transport paths by randomly mutating a single current path (e.g. adding a new vertex to the path). Eac ..."
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Cited by 203 (1 self)
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We present a new Monte Carlo method for solving the light transport problem, inspired by the Metropolis sampling method in computational physics. To render an image, we generate a sequence of light transport paths by randomly mutating a single current path (e.g. adding a new vertex to the path). Each mutation is accepted or rejected with a carefully chosen probability, to ensure that paths are sampled according to the contribution they make to the ideal image. We then estimate this image by sampling many paths, and recording their locations on the image plane. Our algorithm is unbiased, handles general geometric and scattering models, uses little storage, and can be orders of magnitude more e#cient than previous unbiased approaches. It performs especially well on problems that are usually considered di#cult, e.g. those involving bright indirect light, small geometric holes, or glossy surfaces. Furthermore, it is competitive with previous unbiased algorithms even for relatively simple ...
Generating antialiased images at low sampling densities
 In SIGGRAPH ’87: Proceedings of the 14th annual conference on Computer graphics and interactive techniques, ACM
, 1987
"... Ray tracing produces point samples of an image from a 3D model. Constructing an antialiased digital picture from point samples is difficult without resorting to extremely high sampling densities. This paper describes a program that focuses on that problem. While it is impossible to totally eliminat ..."
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Cited by 186 (7 self)
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Ray tracing produces point samples of an image from a 3D model. Constructing an antialiased digital picture from point samples is difficult without resorting to extremely high sampling densities. This paper describes a program that focuses on that problem. While it is impossible to totally eliminate aliasing, it has been shown that nonuniform sampling yields aliasing that is less conspicuous to the observer. An algorithm is presented for fast generation of nonuniform sampling patterns that are optimal in some sense. Some regions of an image may require extra sampling to avoid strong aliasing. Deciding where to do extra sampling can be guided by knowledge of how the eye perceives noise as a function of contrast and color. Finally, to generate the digital picture, the image must be reconstructed from the samples and resampled at the display pixel rate. The nonuniformity of the samples complicates this process, and a new nonuniform reconstruction filter is presented which solves this problem efficiently. This paper was presented in SIGGRAPH 87.
Predicting reflectance functions from complex surfaces
, 1992
"... This thesis describes a physicallybased Monte Carlo technique for approximating bidirectional reflectance distribution functions (BRDFs) for a large class of geometries by directly simulating geometric optical scattering from surfaces. The method is more general than previous analytical models: it ..."
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Cited by 174 (6 self)
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This thesis describes a physicallybased Monte Carlo technique for approximating bidirectional reflectance distribution functions (BRDFs) for a large class of geometries by directly simulating geometric optical scattering from surfaces. The method is more general than previous analytical models: it removes most restrictions on surface microgeometry. Three main points are described: a new representation of the BRDF, a Monte Carlo technique to estimate the coefficients of the representation, and the means of creating a milliscale BRDF from microscale scattering events. The combination of these techniques allows the prediction of scattering from essentially arbitrary roughness geometries. The BRDF is concisely represented by a matrix of spherical harmonic coefficients; the matrix is directly estimated from a geometric optics simulation, enforcing exact reciprocity. Microscale scattering events are represented by direct simulation (e.g., specular reflection and transmission by individual textile fibers) or by a microscaleaveraged model (e.g., a waveopticsbased statistical BRDF) depend
Optimally Combining Sampling Techniques for Monte Carlo Rendering
, 1995
"... Monte Carlo integration is a powerful technique for the evaluation of difficult integrals. Applications in rendering include distribution ray tracing, Monte Carlo path tracing, and formfactor computation for radiosity methods. In these cases variance can often be significantly reduced by drawing sa ..."
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Cited by 173 (2 self)
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Monte Carlo integration is a powerful technique for the evaluation of difficult integrals. Applications in rendering include distribution ray tracing, Monte Carlo path tracing, and formfactor computation for radiosity methods. In these cases variance can often be significantly reduced by drawing samples from several distributions, each designed to sample well some difficult aspect of the integrand. Normally this is done by explicitly partitioning the integration domain into regions that are sampled differently. We present a powerful alternative for constructing robust Monte Carlo estimators, by combining samples from several distributions in a way that is provably good. These estimators are unbiased, and can reduce variance significantly at little additional cost. We present experiments and measurements from several areas in rendering: calculation of glossy highlights from area light sources, the “final gather” pass of some radiosity algorithms, and direct solution of the rendering equation using bidirectional path tracing.
BiDirectional Path Tracing
 PROCEEDINGS OF THIRD INTERNATIONAL CONFERENCE ON COMPUTATIONAL GRAPHICS AND VISUALIZATION TECHNIQUES (COMPUGRAPHICS ’93
, 1993
"... In this paper we present a new Monte Carlo rendering algorithm that seamlessly integrates the ideas of ..."
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Cited by 168 (10 self)
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In this paper we present a new Monte Carlo rendering algorithm that seamlessly integrates the ideas of
Wavelet Radiosity
, 1993
"... Radiosity methods have been shown to be an effective means to solve the global illumination problem in Lambertian diffuse environments. These methods approximate the radiosity integral equation by projecting the unknown radiosity function into a set of basis functions with limited support resulting ..."
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Cited by 165 (10 self)
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Radiosity methods have been shown to be an effective means to solve the global illumination problem in Lambertian diffuse environments. These methods approximate the radiosity integral equation by projecting the unknown radiosity function into a set of basis functions with limited support resulting in a set of n linear equations where n is the number of discrete elements in the scene. Classical radiosity methods required the evaluation of n 2 interaction coefficients. Efforts to reduce the number of required coefficients without compromising error bounds have focused on raising the order of the basis functions, meshing, accounting for discontinuities, and on developing hierarchical approaches, which have been shown to reduce the required interactions to O(n). In this paper we show that the hierarchical radiosity formulation is an instance of a more general set of methods based on wavelet theory. This general framework offers a unified view of both higher order element approaches to...
A Perceptually Based Physical Error Metric for Realistic Image Synthesis
, 1999
"... We introduce a new concept for accelerating realistic image synthesis algorithms. At the core of this procedure is a novel physical error metric that correctly predicts the perceptual threshold for detecting artifacts in scene features. Built into this metric is a computational model of the human vi ..."
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Cited by 152 (7 self)
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We introduce a new concept for accelerating realistic image synthesis algorithms. At the core of this procedure is a novel physical error metric that correctly predicts the perceptual threshold for detecting artifacts in scene features. Built into this metric is a computational model of the human visual system's loss of sensitivity at high background illumination levels, high spatial frequencies, and high contrast levels (visual masking). An important feature of our model is that it handles the luminancedependent processing and spatiallydependent processing independently. This allows us to precompute the expensive spatiallydependent component, making our model extremely efficient. We illustrate the utility of our procedure with global illumination algorithms used for realistic image synthesis. The expense of global illumination computations is many orders of magnitude higher than the expense of direct illumination computations and can greatly benefit by applying our perceptually bas...
Photon Mapping on Programmable Graphics Hardware
 GRAPHICS HARDWARE
, 2003
"... We present a modified photon mapping algorithm capable of running entirely on GPUs. Our implementation uses breadthfirst photon tracing to distribute photons using the GPU. The photons are stored in a gridbased photon map that is constructed directly on the graphics hardware using one of two met ..."
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Cited by 151 (4 self)
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We present a modified photon mapping algorithm capable of running entirely on GPUs. Our implementation uses breadthfirst photon tracing to distribute photons using the GPU. The photons are stored in a gridbased photon map that is constructed directly on the graphics hardware using one of two methods: the first method is a multipass technique that uses fragment programs to directly sort the photons into a compact grid. The second method uses a single rendering pass combining a vertex program and the stencil buffer to route photons to their respective grid cells, producing an approximate photon map. We also present an efficient method for locating the nearest photons in the grid, which makes it possible to compute an estimate of the radiance at any surface location in the scene. Finally, we describe a breadthfirst stochastic ray tracer that uses the photon map to simulate full global illumination directly on the graphics hardware. Our implementation demonstrates that current graphics hardware is capable of fully simulating global illumination with progressive, interactive feedback to the user.
A survey of shadow algorithms
 IEEE Computer Graphics and Applications
, 1990
"... Essential to realistic and visually appealing images, shadows are difficult ta compute in most display environments. This survey characterizes the various types of shadows. It also describes most existing shadow algorithms and discusses their complexities, advantages, and shommings. We examine herd ..."
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Cited by 147 (3 self)
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Essential to realistic and visually appealing images, shadows are difficult ta compute in most display environments. This survey characterizes the various types of shadows. It also describes most existing shadow algorithms and discusses their complexities, advantages, and shommings. We examine herd shadows, soft shadbws, shadows of transparent objects, and shadows for complex modeling primitives. For each type, we examine shadow algorithms within various rendswing techniques. This survey attempts to provide readem with enough background and insight on the various rmthods to dow them to choose the algorithm best wpuited to their W. We also hope that our analysis will h&p identify the a m that need more research and point bo possible sotutkms. A shadowa region of relative darkness within an not necessarily attenuate the light it occludes. In fact, illuminated regionoccurs when an object totally or it can concentrate light. However, as is traditional in partially occludes the light. A transparent object does image synthesis, lve will consider a region to be in