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Proton: Multitouch Gestures as Regular Expressions Kenrick Kin, Bjoern Hartmann, Tony DeRose, Maneesh Agrawala January 2012 Current multitouch frameworks require application developers to write recognition code for custom gestures; this code is split across multiple event-handling callbacks. As the number of custom gestures grows it becomes increasingly difficult to 1) know if new gestures will conflict with existing gestures, and 2) know how to extend existing ... [more] To appear in CHI 2012 Available as Pixar Technical Memo #12-02 |
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Importance Sampling of Reflections from Hair Fibers Christophe Hery, Ravi Ramamoorthi December 2011 Hair and fur are increasingly important visual features in production rendering, and physically-based light scattering models are now commonly used. In this paper, we enable efficient Monte Carlo rendering of reflections from hair fibers by describing a simple and practical importance sampling strategy for the reflection term in the Marschner hair model. Our ... [more] Available as Pixar Technical Memo #11-07 |
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Eden: A Professional Multitouch Tool for Constructing Virtual Organic Environments Kenrick Kin, Tom Miller, Bjoern Bollensdorff, Tony DeRose, Bjoern Hartmann, Maneesh Agrawala January 2011 Set construction is the process of selecting and positioning virtual geometric objects to create a virtual environment used in a computer-animated film. Set construction artists often have a clear mental image of the set composition, but find it tedious to build their intended sets with current mouse and keyboard interfaces. We investigate whether multitouch input can ... [more] To appear in the proceedings of SIGCHI 2011 Available as Pixar Technical Memo #11-04 |
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Point-Based Global Illumination for Movie Production Per H. Christensen July 2010 This course note describes a fast point-based method for computing diffuse and glossy global illumination, area light illumination and soft shadows, HDRI environment map illumination, multiple diffuse reflection bounces, final gathering for photon mapping, ambient occlusion, reflection occlusion, and volume scattering. The results are free of noise and the ... [more] Additional materials: [Slides.pdf] |
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Smoothed Local Histogram Filters Michael Kass, Justin Solomon May 2010 Local image histograms contain a great deal of information useful for applications in computer graphics, computer vision and computational photography. Making use of that information has been challenging because of the expense of computing histogram properties over large neighborhoods. Efficient algorithms exist for some specific computations like the bilateral filter, but not others. ... [more] To appear in the Proceedings of SIGGRAPH 2010 Available as Pixar Technical Memo #10-02 |
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Determining the Benefits of Direct-Touch, Bimanual, and Multifinger Input on a Multitouch Workstation Kenrick Kin, Maneesh Agrawala, Tony DeRose May 2009 Multitouch workstations support direct-touch, bimanual, and multifinger interaction. Previous studies have separately examined the benefits of these three interaction attributes over mouse-based interactions. In contrast, we present an empirical user study that considers these three interaction attributes together for a single task, such that we can quantify and compare the performances of each attribute. In our ... [more] To appear in Graphics Interface 2009 |
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Point-Based Approximate Color Bleeding Per H. Christensen July 2008 This technical memo describes a fast point-based method for computing diffuse global illumination (color bleeding). The computation is 4-10 times faster than ray tracing, uses less memory, has no noise, and its run-time does not increase due to displacement-mapped surfaces, complex shaders, or many complex light sources. These properties make the method suitable ... [more] Additional materials: [SlidesFromAnnecy09.pdf] Available as Pixar Technical Memo #08-01 |
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Animating Oscillatory Motion With Overlap: Wiggly Splines Michael Kass, John Anderson June 2008 Oscillatory motion is ubiquitous in computer graphics, yet existing animation techniques are ill-suited to its authoring. We introduce a new type of spline for this purpose, known as a ``Wiggly Spline.'' The spline generalizes traditional piecewise cubics when its resonance and damping are set to zero, but creates oscillatory animation when its resonance and damping ... [more] Available in SIGGRAPH 2008 Available as Pixar Technical Memo #06-06a Other versions: |
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Volume Conserving Finite Element Simulations of Deformable Models Geoffrey Irving, Craig Schroeder, Ronald Fedkiw August 2007 We propose a numerical method for modeling highly deformable nonlinear incompressible solids that conserves the volume locally near each node in a finite element mesh. Our method works with arbitrary constitutive models, is applicable to both passive and active materials (e.g. muscles), and works with simple tetrahedra without the need for multiple quadrature points ... [more] Available in the proceedings of SIGGRAPH 2007. |
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High-Quality Rendering Using Ray Tracing and Photon Mapping Henrik Wann Jensen, Per H. Christensen August 2007 Detailed descriptions of the ray-tracing and photon-mapping algorithms for rendering complex scenes with indirect illumination, caustics, participating media, and subsurface scattering. The emphasis is on the practical insight necessary to use and implement these algorithms in production of high-quality image in movies, games, architecture, etc. Available as Siggraph 2007 course notes, Course Number 8 |
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Anyone Can Cook -- Inside Ratatouille's Kitchen Jun Han Cho, Athena Xenakis, Stefan Gronsky, Apurva Shah July 2007 The passion for cooking and food are the central theme of Pixar's recent film - Ratatouille. This complex and multi-faceted problem posed many challenges that were solved using diverse computer graphics and production techniques. In this course we will comprehensively cover all aspects including modeling, dressing, shading, lighting and effects.
The ... [more] |
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Rat-Sized Water Effects in Ratatouille Gary Bruins, Jon Reisch May 2007 A particularly heavy effects sequence in the film Ratatouille depicts a colony of rats fleeing their home and crossing a long narrow river in several makeshift boats during a rainy afternoon. Nearly the entire sequence was photographed inches above the ground from a s perspective. Although this perspective provided a very interesting point of view ... [more] Available as Pixar Technical Memo #07-14 |
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Effective Toon-Style Rendering Control Using Scalar Fields Alex Harvill May 2007 An illustration of Gusteau comes to life and introduces a new facet of the film Ratatouille. To do this, a technique was needed to convert an animated 3D character into a 2D illustration. Existing renderman shaders based on normal and depth maps were difficult to control. Post processing per gprim id ... [more] Available as Pixar Technical Memo #07-08 |
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3D Paint Baking Proposal Robert L. Cook May 2007 3d paint has long been one of the most expensive parts of rendering at Pixar. This proposal is for a new baking technique that would greatly reduce the run-time cost of 3d paint and require no changes to the existing workflow. The implementation makes heavy use of existing code, which ... [more] Available as Pixar Technical Memo #07-16 |
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Harmonic Coordinates for Character Articulation Pushkar Joshi, Mark Meyer, Tony DeRose, Brian Green, Tom Sanocki May 2007 In this paper we consider the problem of creating and controlling volume deformations used to articulate characters for use in high-end applications such as computer generated feature films. We introduce a method we call harmonic coordinates that significantly improves upon existing volume deformation techniques. Our deformations are controlled using a topologically flexible structure, called a cage, ... [more] Additional materials: [SiggraphSlides.pdf], [HarmonicCoordinates.divx] Available in the proceedings of Siggraph 2007. Available as Pixar Technical Memo #06-02b Other versions: |
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Key Point Subspace Acceleration and Soft Caching Mark Meyer, John Anderson May 2007 Many applications in Computer Graphics contain computationally expensive calculations. These calculations are often performed at many points to produce a full solution, even though the subspace of reasonable solutions may be of a relatively low dimension. The calculation of facial articulation and rendering of scenes with global illumination are two example applications that ... [more] Additional materials: [SiggraphSlides.pdf], [softCaching.mov] Available in the proceedings of Siggraph 2007 Available as Pixar Technical Memo #06-04b Other versions: |
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Virtual Tailoring for Ratatouille: Clothing the Fattest Man in the World Christine Waggoner, David Baraff May 2007 He's fat. Enormously so. Essentially a clothed sphere. (A very deformable and complexly animated sphere, with legs, arms, and no neck.) For Ratatouille, creating dynamic costumes for every human character in the film required extensive development and innovation in Pixar's cloth pipeline, particularly for the character Gusteau. Modeling and shepherding ... [more] Available as Pixar Technical Memo #07-07 |
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500 Million and Counting: Hair Rendering on Ratatouille David Ryu May 2007 Featuring plush rats, well-groomed humans, and a colony of rodents numbering a thousand strong, Ratatouille had shots where the original scene descriptions contained many hundreds of millions of hairs. To make these shots renderable, we developed many new technologies to optimize our RenderMan-based hair rendering pipeline, including caching to speed up runtime sculpting, a technique ... [more] Available as Pixar Technical Memo #07-09 |
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Chop It Up! Animation-Driven Modeling, Simulation, and Shading in the Kitchen Patrick Coleman, Eric Froemling May 2007 In Disney/Pixar's Ratatouille, the creation of believable cooking environments with all their complexity has been an important element in presenting a rich world that helps draw the audience into the story. Part of that complexity arises in the preparation of food before cooking. To create complex animations of food in preparation, we designed a system ... [more] Available as Pixar Technical Memo #07-13 |
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Simulating Whitewater Rapids in Ratatouille Eric Froemling, Tolga Goktekin, Darwyn Peachey May 2007 In Pixar's Ratatouille, a key story point involves a rat being swept through the sewers of Paris, plummeting down waterfalls and along steeply sloping tunnels, through a series of high-speed S- bends which cause the torrent of water to bank up sharply on each turn. Bringing ... [more] Available as Pixar Technical Memo #07-03 |
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Fast, Soft Reflections Using Radiance Caches Apurva Shah, Justin Ritter, Chris King, Stefan Gronsky May 2007 In Pixar's Ratatouille a lot of scenes take place inside the kitchen where reflective surfaces like counter tops, stoves, pots and pans abound. Furthermore, these surfaces were often burnished or covered with dents, scratches or other displacements, which meant that the reflections were soft and fuzzy. Physically accurate reflections are most ... [more] Available as Pixar Technical Memo #07-04 |
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Extracting and Parametrizing Temporally Coherent Surfaces from Particles Chen Shen, Apurva Shah May 2007 From pouring sauces to sudsy sink water to violent sewer rapids, realistic animation of fluids presented interesting challenges in Ratatouille. The various fluid effects were simulated either using a physically-based solver or directly with generic particle systems. Although the simulated particles move as a whole like a fluid, the number ... [more] Available as Pixar Technical Memo #07-05 |
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An Effects Recipe for Rolling Dough, Cracking Eggs and Pouring Sauce Tolga Goktekin, Jon Reisch, Darwyn Peachey, Apurva Shah May 2007 Creating the digital effects for cooking in Ratatouille posed a number of unique challanges. First we had to adopt efficient methods for simulating a wide variety of material behaviours. Second we needed to direct our simulations in order to match the expressiveness of the character's animation, e.g. forming specific shapes while the character pounds a ... [more] Available as Pixar Technical Memo #07-06 |
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Acting with Contact in Ratatouille - Cartoon Collision and Response Gordon Cameron, Robert Russ, Adam Woodbury May 2007 Contact is natural in the real world but often avoided in 3D animated features. Animators tend to make acting decisions that minimise or avoid contact within and between their characters and the world, and when apparent contact does occur, it can tend to feel both "floaty" and unrealistic. "Ratatouille" called for dynamic, tactile characters that ... [more] Available as Pixar Technical Memo #07-10 |
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Stochastic Simplification of Aggregate Detail Robert L. Cook, John Halstead, Maxwell Planck, David Ryu May 2007 Many renderers perform poorly on scenes that contain a lot of detailed geometry. The load on the renderer can be alleviated by simplification techniques, which create less expensive representations of geometry that is small on the screen. Current simplification techniques for high-quality surface-based rendering tend to work best with element ... [more] Additional materials: [SiggraphSlides.pdf], [WithAndWithoutSimplification.mov] Available in the Proceedings of Siggraph 2007. Available as Pixar Technical Memo #06-05a Other versions: |
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Articulating the Appeal Sonoko Konishi, Michael Venturini May 2007 It's difficult. In our society, rodents are usual portrayed in a negative manner. To overcome this, every department on Ratatouille strove to create appeal. In this sketch we will focus on how this was achieved through articulation. Available as Pixar Technical Memo #07-12 |
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Rivers of Rodents: An Animation-Centric Crowds Pipeline for
Ratatouille David Ryu, Paul Kanyuk May 2007 One of the major technical challenges in the animated film Ratatouille was creating a believable rat colony. In numbers as high as a thousand, these rats participated in highly complex and coordinated behaviors ranging from chaotic swarming to gourmet cooking. Often, the colony was ... [more] Available as Pixar Technical Memo #07-02 |
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Ray Tracing for the Movie 'Cars' Per H. Christensen, Julian Fong, David M. Laur, Dana Batali September 2006 This paper describes how we extended Pixar's RenderMan renderer with ray tracing abilities. In order to ray trace highly complex scenes we use multiresolution geometry and texture caches, and use ray differentials to determine the appropriate resolution. With this method we are able to efficiently ray trace scenes with much more geometry and ... [more] Available in Proceedings of the IEEE Symposium on Interactive Ray Tracing 2006, pages 1-6. IEEE 2006 |
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Efficient Simulation of Large Bodies of Water by Coupling Two and Three Dimensional Techniques Geoffrey Irving, Eran Guendelman, Frank Losasso, Ronald Fedkiw January 2006 We present a new method for the efficient simulation of large bodies of water, especially effective when three-dimensional surface effects are important. Similar to a traditional two-dimensional height field approach, most of the water volume is represented by tall cells which are assumed to have linear pressure profiles. In order to avoid the limitations typically ... [more] Additional materials: [movie.avi] Available in the proceedings of SIGGRAPH 2006 |
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Interactive Depth of Field Michael Kass, Aaron Lefohn, John Owens January 2006 Accurate computation of depth-of-field effects in computer graphics rendering is generally very time consuming, creating a problematic workflow for film authoring. The computation is particularly challenging because it depends on large-scale spatially-varying filtering that must accurately respect complex boundaries. Here we introduce an approximate depth-of-field computation that is good enough for film preview, yet ... [more] Additional materials: [movie.avi] Available as Pixar Technical Memo #06-01 |
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Statistical Acceleration for Animated Global Illumination Mark Meyer, John Anderson January 2006 Global illumination provides important visual cues to an animation, however its computational expense limits its use in practice. In this paper, we present an easy to implement technique for accelerating the computation of indirect illumination for an animated sequence using stochastic ray tracing. We begin by computing a quick but noisy solution using a ... [more] Additional materials: [ShotRender.mov] To appear in SIGGRAPH 2006 Available as Pixar Technical Memo #06-03 |
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Lpics: a Hybrid Hardware-Accelerated Relighting Engine for
Computer Cinematography Fabio Pellacini, Kiril Vidimce, Aaron Lefohn, Alex Mohr, Mark Leone, John Warren August 2005 In computer cinematography, the process of lighting design involves placing and configuring lights to define the visual appearance of environments and to enhance story elements. This process is labor intensive and time consuming, primarily because ... [more] Additional materials: [lpics_siggraph.mp4] Available in the Proceedings of SIGGRAPH 2005 |
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Wavelet Noise Robert L. Cook, Tony DeRose August 2005 Noise functions are an essential building block for writing procedural shaders in 3D computer graphics. The original noise function introduced by Ken Perlin is still the most popular because it is simple and fast, and many spectacular images have been made ... [more] Additional materials: [RapLyrics.txt] Available in the Proceedings of SIGGRAPH 2005 |
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Volumetric Methods for Simulation and Rendering of Hair Lena Petrovic, Mark Henne, John Anderson January 2005 Hair is one of the crucial elements in representing believable digital humans. It is one of the most challenging elements, too, due to the large number of hairs on a human head, their length, and their complex interactions. Hair appearance, in rendering and simulation, is ... [more] Additional materials: [clip1.mp4], [clip4.mp4], [clip2.mp4], [clip5.mp4], [clip6.mp4], [clip3.mp4] Available as Pixar Technical Memo #06-08 |
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Mio: Fast Multipass Partitioning via Priority-Based Instruction Scheduling Andrew Riffel, Aaron Lefohn, Kiril Vidimce, Mark Leone, John Owens August 2004 Real-time graphics hardware continues to offer improved resources for programmable vertex and fragment shaders. However, shader programmers continue to write shaders that require more resources than are available in the hardware. One way to virtualize the resources necessary to run complex shaders is to partition the ... [more] Available in the Proceedings of Graphics Hardware 2004 |
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An Irradiance Atlas for Global Illumination in Complex Production Scenes Per H. Christensen, Dana Batali June 2004 We introduce a tiled 3D MIP map representation of global illumination data. The representation is an adaptive sparse octree with a "brick" at each octree node; each brick consists of 8 cubed voxels with sparse irradiance values. The representation is designed to enable efficient caching. Combined with ... [more] Published as pp. 133-141 in the Proceedings of the Eurographics Symposium on Rendering 2004, Eurographics/ACM, June 2004. |
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Ray Differentials and Multiresolution Geometry Caching for Distribution Ray
Tracing in Complex Scenes Per H. Christensen, David M. Laur, Julian Fong, Wayne L. Wooten, Dana Batali September 2003 When rendering only directly visible objects, ray tracing a few levels of specular reflection from large, low curvatures surfaces, and ray tracing shadows from point-like light sources, the accessed geometry is coherent and a geometry cache performs well. But in many other cases, ... [more] Published as pp. pp. 543-552 in Computer Graphics Forum (Eurographics 2003 Conference Proceedings), Blackwell Publishers, September 2003. |
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Untangling Cloth David Baraff, Andrew Witkin, Michael Kass August 2003 Deficient cloth-to-cloth collision response is the most serious shortcoming of most cloth simulation systems. Past approaches to cloth-cloth collision have used history to decide wheter nearby cloth regions have interpenetrated. The biggest pitfall of history-based methods is that an error anywhere along the way can give rise to persistent tangles...This ... [more] Available in the Proceedings of SIGGRAPH 2003 |
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RenderMan, Theory and Practice Dana Batali, Byron Bashforth, Chris Bernardi, Per H. Christensen, David M. Laur, Christophe Hery, Guido Quaroni, Erin Tomson, Thomas Jordan, Wayne L. Wooten July 2003 Siggraph 2003 course notes. |
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Adjoints and Importance in Rendering: an Overview Per H. Christensen July 2003 This survey gives an overview of the use of importance, an adjoint of light, in speeding up rendering. The importance of a light distribution indicates its contribution to the region of most interest --- typically the directly visible parts of a scene. Importance can therefore be used to concentrate global illumination and ray ... [more] Available as IEEE Transactions on Visualization and Computer Graphics (TVCG), Volume 9, Number 3, pages 329-340. IEEE, July 2003. |
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Advanced Issues in Level of Detail Martin Reddy August 2002 Siggraph 2002 course slides. See the abstracts in the additional materials below for more details. Additional materials: [4-terrain.pdf], [3-terrain-abstract.txt], [2-perception.pdf], [1-perception-abstract.txt] |
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Deep Shadow Maps Tom Lokovic, Eric Veach August 2000 We introduce deep shadow maps, a technique that produces fast, high-quality shadows for primitives such as hair, fur, and smoke. Unlike traditional shadow maps, which store a single depth at each pixel, deep shadow maps store a representation of the fractional visibility through a pixel at all possible depths. Deep ... [more] Available in the Proceedings of SIGGRAPH 2000. |
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Subdivision Surfaces in Character Animation Tony DeRose, Michael Kass, Tien Truong August 1998 The creation of believable and endearing characters in computer graphics presents a number of technical challenges, including the modeling, animation and rendering of complex shapes such as heads, hands, and clothing. Traditionally, these shapes have been modeled ... [more] Available in the Proceedings of SIGGRAPH 1998. |
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Dinosaur Input Device Brian Knep, Craig Hayes, Rick Sayre, Tom Williams June 1995 We present a system for animating an articulate figure using a physical skeleton, or armature, connected to a workstation. The skeleton is covered with sensors that monitor the orientations of the joints and send this information to the computer via custom-built hardware. ... [more] Appeared in the Proceedings of SIGCHI 1995 |
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Texture On Demand Darwyn Peachey 1990 Texture On Demand (TOD) is a technique for organizing large amounts of stored texture data in disk files and accessing it efficiently. Simply reading entire texture images into memory is not a good solution for real memory systems or for virtual memory systems. Texture data should be read from disk files only on ... [more] Available as Pixar Technical Memo #217 |
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Rendering Antialiased Shadows with Depth Maps Bill Reeves, David Salesin, Robert L. Cook July 1987 We present a solution to the aliasing problem for shadow algorithms that use depth maps. The solution is based on a new filtering technique called percentage closer filtering. In addition to antialiasing, the improved algorithm provides soft shadow boundaries that resemble penumbrae. We describe ... [more] Available in the Proceedings of SIGGRAPH 1987. |
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The Reyes Rendering Architecture Robert L. Cook, Loren Carpenter, Edwin Catmull July 1987 An architecture is presented for fast high-quality rendering of complex images. All objects are reduced to common world-space geometric entities called micropolygons, and all of the shading and visibility calculations operate on these micropolygons. Each type of calculation is performed in a coordinate system that is ... [more] |
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Stochastic Sampling in Computer Graphics Robert L. Cook January 1986 Ray tracing, ray casting, and other forms of point sampling are important techniques in computer graphics, but their usefulness has been undermined by aliasing artifacts. In this paper it is shown that these artifacts are not an inherent part of point sampling, but a consequence of ... [more] Available in ACM Transactions on Graphics, Volume 6, Number 1, January 1996. |
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Distributed Ray Tracing Robert L. Cook, Thomas Porter, Loren Carpenter July 1984 Ray tracing is one of the most elegant techniques in computer graphics. Many phenomena that are difficult or impossible with other techniques are simple with ray tracing, including shadows, reflections, and refracted light. Ray directions, however, have been determined precisely, and this had limited the capabilities of ray tracing. By ... [more] Available in the Proceedings of SIGGRAPH 1984 |
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Compositing Digital Images Thomas Porter, Tom Duff July 1984 Most computer graphics pictures have been computed all at once, so that the rendering program takes care of all computations relating to the overlap of objects. There are several applications, however, where elements must be rendered separately, relying on compositing techniques for the anti-aliased accumulation of the full image. This ... [more] Available in the Proceedings of SIGGRAPH 1984. |
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Shade Trees Robert L. Cook July 1984 Shading is an important part of computer imagery, but shaders have been based on fixed models to which all surfaces must conform. As computer imagery becomes more sophisticated, surfaces have more complex shading characteristics and thus require a less rigid shading model. This paper presents a flexible tree-structured shading model ... [more] Available in the Proceedings of SIGGRAPH 1984. |
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A Reflectance Model for Computer Graphics Robert L. Cook, Kenneth E. Torrance January 1982 A new reflectance model for rendering computer sythesized images is presented. The model accounts for the relative brightness of different materials and light sources in the same scene. It describes the directional distribution of the reflected light and a color shift that occurs as ... [more] Published in Transactions on Graphics, Vol. 1, No. 1, January 1982. |