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 has limited the capabilities of ray tracing. By distributing the directions of the rays according to the analytic function they sample, ray tracing can incorporate fuzzy phenomena. This provides correct and easy solutions to some previously unsolved or partially solved problems, including motion blur, depth of field, penumbras, translucency, and fuzzy reflections. Motion blur and depth of field calculations can be integrated with the visible surface calculations, avoiding the problems found in previous methods.
{"title":"Distributed ray tracing","authors":"R. L. Cook, Thomas K. Porter, L. Carpenter","doi":"10.1145/280811.280978","DOIUrl":"https://doi.org/10.1145/280811.280978","url":null,"abstract":"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 has limited the capabilities of ray tracing. By distributing the directions of the rays according to the analytic function they sample, ray tracing can incorporate fuzzy phenomena. This provides correct and easy solutions to some previously unsolved or partially solved problems, including motion blur, depth of field, penumbras, translucency, and fuzzy reflections. Motion blur and depth of field calculations can be integrated with the visible surface calculations, avoiding the problems found in previous methods.","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123468289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shadowing has historically been used to increase the intelligibility of scenes in electron microscopy and aerial survey. Various methods have been published for the determination of shadows in computer synthesized scenes. The display of shadows may make the shape and relative position of objects in such scenes more comprehensible; it is a technique lending vividness and realism to computer animation. To date, algorithms for the determination of shadows have been restricted to scenes constructed of planar polygons. A simple algorithm is described which utilizes Z-buffer visible surface computation to display shadows cast by objects modelled of smooth surface patches. The method can be applied to all environments, in fact, for which visible surfaces can be computed. The cost of determining the shadows associated with each light source is roughly twice the cost of rendering the scene without shadows, plus a fixed transformation overhead which depends on the image resolution. No extra entities are added to the scene description in the shadowing process. This comprehensive algorithm, which permits curved shadows to be cast on curved surfaces, is contrasted with a less costly method for casting the shadows of the environment on a single ground plane. In order to attain good results, the discrete nature of the visible-surface computations must be treated with care. The effects of dither, interpolation, and geometric quantization at different stages of the shadowing algorithm are examined. The special problems posed by self-shadowing surfaces are described.
{"title":"Casting curved shadows on curved surfaces","authors":"Lance Williams","doi":"10.1145/280811.280975","DOIUrl":"https://doi.org/10.1145/280811.280975","url":null,"abstract":"Shadowing has historically been used to increase the intelligibility of scenes in electron microscopy and aerial survey. Various methods have been published for the determination of shadows in computer synthesized scenes. The display of shadows may make the shape and relative position of objects in such scenes more comprehensible; it is a technique lending vividness and realism to computer animation. To date, algorithms for the determination of shadows have been restricted to scenes constructed of planar polygons. A simple algorithm is described which utilizes Z-buffer visible surface computation to display shadows cast by objects modelled of smooth surface patches. The method can be applied to all environments, in fact, for which visible surfaces can be computed. The cost of determining the shadows associated with each light source is roughly twice the cost of rendering the scene without shadows, plus a fixed transformation overhead which depends on the image resolution. No extra entities are added to the scene description in the shadowing process. This comprehensive algorithm, which permits curved shadows to be cast on curved surfaces, is contrasted with a less costly method for casting the shadows of the environment on a single ground plane. In order to attain good results, the discrete nature of the visible-surface computations must be treated with care. The effects of dither, interpolation, and geometric quantization at different stages of the shadowing algorithm are examined. The special problems posed by self-shadowing surfaces are described.","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125871334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We introduce the concept of a Pixel Stream Editor. This forms the basis for an interactive synthesizer for designing highly realistic Computer Generated Imagery. The designer works in an interactive Very High Level programming environment which provides a very fast concept/implement/view iteration cycle.Naturalistic visual complexity is built up by composition of non-linear functions, as opposed to the more conventional texture mapping or growth model algorithms. Powerful primitives are included for creating controlled stochastic effects. We introduce the concept of "solid texture" to the field of CGI.We have used this system to create very convincing representations of clouds, fire, water, stars, marble, wood, rock, soap films and crystal. The algorithms created with this paradigm are generally extremely fast, highly realistic, and asynchronously parallelizable at the pixel level.
我们介绍了像素流编辑器的概念。这构成了设计高度逼真的计算机生成图像的交互式合成器的基础。设计师在一个交互式的Very High Level编程环境中工作，这提供了一个非常快的概念/实现/视图迭代周期。自然的视觉复杂性是通过非线性函数的组合来建立的，这与更传统的纹理映射或增长模型算法相反。包括用于创建受控随机效果的强大原语。我们将“实体纹理”的概念引入到CGI领域。我们用这个系统创造了云、火、水、星星、大理石、木头、岩石、肥皂膜和水晶的非常令人信服的表现。使用此范例创建的算法通常非常快，高度逼真，并且在像素级别上可异步并行化。
{"title":"An image synthesizer","authors":"K. Perlin","doi":"10.1145/280811.280986","DOIUrl":"https://doi.org/10.1145/280811.280986","url":null,"abstract":"We introduce the concept of a Pixel Stream Editor. This forms the basis for an interactive synthesizer for designing highly realistic Computer Generated Imagery. The designer works in an interactive Very High Level programming environment which provides a very fast concept/implement/view iteration cycle.Naturalistic visual complexity is built up by composition of non-linear functions, as opposed to the more conventional texture mapping or growth model algorithms. Powerful primitives are included for creating controlled stochastic effects. We introduce the concept of \"solid texture\" to the field of CGI.We have used this system to create very convincing representations of clouds, fire, water, stars, marble, wood, rock, soap films and crystal. The algorithms created with this paradigm are generally extremely fast, highly realistic, and asynchronously parallelizable at the pixel level.","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132626797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A technique for rendering images of volumes containing mixtures of materials is presented. The shading model allows both the interior of a material and the boundary between materials to be colored. Image projection is performed by simulating the absorption of light along the ray path to the eye. The algorithms used are designed to avoid artifacts caused by aliasing and quantization and can be efficiently implemented on an image computer. Images from a variety of applications are shown.
{"title":"Volume rendering","authors":"R. A. Drebin, L. Carpenter, P. Hanrahan","doi":"10.1145/280811.281028","DOIUrl":"https://doi.org/10.1145/280811.281028","url":null,"abstract":"A technique for rendering images of volumes containing mixtures of materials is presented. The shading model allows both the interior of a material and the boundary between materials to be colored. Image projection is performed by simulating the absorption of light along the ray path to the eye. The algorithms used are designed to avoid artifacts caused by aliasing and quantization and can be efficiently implemented on an image computer. Images from a variety of applications are shown.","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126881633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aggregate motion of a flock of birds, a herd of land animals, or a school of fish is a beautiful and familiar part of the natural world. But this type of complex motion is rarely seen in computer animation. This paper explores an approach based on simulation as an alternative to scripting the paths of each bird individually. The simulated flock is an elaboration of a particle systems, with the simulated birds being the particles. The aggregate motion of the simulated flock is created by a distributed behavioral model much like that at work in a natural flock; the birds choose their own course. Each simulated bird is implemented as an independent actor that navigates according to its local perception of the dynamic environment, the laws of simulated physics that rule its motion, and a set of behaviors programmed into it by the "animator." The aggregate motion of the simulated flock is the result of the dense interaction of the relatively simple behaviors of the individual simulated birds.
{"title":"Flocks, herds, and schools: a distributed behavioral model","authors":"Craig W. Reynolds","doi":"10.1145/280811.281008","DOIUrl":"https://doi.org/10.1145/280811.281008","url":null,"abstract":"The aggregate motion of a flock of birds, a herd of land animals, or a school of fish is a beautiful and familiar part of the natural world. But this type of complex motion is rarely seen in computer animation. This paper explores an approach based on simulation as an alternative to scripting the paths of each bird individually. The simulated flock is an elaboration of a particle systems, with the simulated birds being the particles. The aggregate motion of the simulated flock is created by a distributed behavioral model much like that at work in a natural flock; the birds choose their own course. Each simulated bird is implemented as an independent actor that navigates according to its local perception of the dynamic environment, the laws of simulated physics that rule its motion, and a set of behaviors programmed into it by the \"animator.\" The aggregate motion of the simulated flock is the result of the dense interaction of the relatively simple behaviors of the individual simulated birds.","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129106524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes a method for recursively generating surfaces that approximate points lying-on a mesh of arbitrary topology. The method is presented as a generalization of a recursive bicubic 8-spline patch subdivision algorithm. For rectangular control-point meshes, the method generates a standard 8-spline surface. For nonrectangular meshes, it yenerates surfaces that are shown to reduce to a standard 8-spline surface except at a small number of points, called extraordinary points. Therefore, everywhere except at these points the surface is continuous in tangent and curvature. At the extraordinary points, the pictures of the surface indicate that the surface is at least continuous in tangent, but no proof of continuity is given. A similar algorithm for biquadratic 8-splines is also presented.
{"title":"Recursively generated B-spline surfaces on arbitrary topological meshes","authors":"E. Catmull, J. Clark","doi":"10.1145/280811.280992","DOIUrl":"https://doi.org/10.1145/280811.280992","url":null,"abstract":"This paper describes a method for recursively generating surfaces that approximate points lying-on a mesh of arbitrary topology. The method is presented as a generalization of a recursive bicubic 8-spline patch subdivision algorithm. For rectangular control-point meshes, the method generates a standard 8-spline surface. For nonrectangular meshes, it yenerates surfaces that are shown to reduce to a standard 8-spline surface except at a small number of points, called extraordinary points. Therefore, everywhere except at these points the surface is continuous in tangent and curvature. At the extraordinary points, the pictures of the surface indicate that the surface is at least continuous in tangent, but no proof of continuity is given. A similar algorithm for biquadratic 8-splines is also presented.","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127837209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The behaviour of the limit surface defined by a recursive division construction can be analysed in terms of the eigenvalues of a set of matrices. This analysis predicts effects actually observed, and leads to suggestions for the further improvement of the method.
{"title":"Behaviour of recursive division surfaces near extraordinary points","authors":"D. Doo, M. Sabin","doi":"10.1145/280811.280991","DOIUrl":"https://doi.org/10.1145/280811.280991","url":null,"abstract":"The behaviour of the limit surface defined by a recursive division construction can be analysed in terms of the eigenvalues of a set of matrices. This analysis predicts effects actually observed, and leads to suggestions for the further improvement of the method.","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114779484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An algorithm is given for computer control of a digital plotter. The algorithm may be programmed without multiplication or division instructions and is efficient with respect to speed of execution and memory utilization.
{"title":"Algorithm for computer control of a digital plotter","authors":"J. Bresenham","doi":"10.1145/280811.280913","DOIUrl":"https://doi.org/10.1145/280811.280913","url":null,"abstract":"An algorithm is given for computer control of a digital plotter. The algorithm may be programmed without multiplication or division instructions and is efficient with respect to speed of execution and memory utilization.","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1965-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130030357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Seminal graphics: pioneering efforts that shaped the field","authors":"R. J. Wolfe","doi":"10.1145/280811","DOIUrl":"https://doi.org/10.1145/280811","url":null,"abstract":"","PeriodicalId":236803,"journal":{"name":"Seminal graphics: pioneering efforts that shaped the field","volume":"446 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122483281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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