A new algorithm for speeding up ray-object intersection calculations is presented. Objects are bounded by a new type of extent, which can be made to fit convex hulls arbitrarily tightly. The objects are placed into a hierarchy. A new hierarchy traversal algorithm is presented which is efficient in the sense that objects along the ray are queried in an efficient order.Results are presented which demonstrate that our technique is several times faster than other published algorithms. Furthermore, we demonstrate that it is currently possible to ray trace scenes containing hundreds of thousands of objects.
{"title":"Ray tracing complex scenes","authors":"Timothy L. Kay, J. Kajiya","doi":"10.1145/15922.15916","DOIUrl":"https://doi.org/10.1145/15922.15916","url":null,"abstract":"A new algorithm for speeding up ray-object intersection calculations is presented. Objects are bounded by a new type of extent, which can be made to fit convex hulls arbitrarily tightly. The objects are placed into a hierarchy. A new hierarchy traversal algorithm is presented which is efficient in the sense that objects along the ray are queried in an efficient order.Results are presented which demonstrate that our technique is several times faster than other published algorithms. Furthermore, we demonstrate that it is currently possible to ray trace scenes containing hundreds of thousands of objects.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"2011 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86327402","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 present a simple model for the surface of the ocean, suitable for the modeling and rendering of most common waves where the disturbing force is from the wind and the restoring force from gravity.It is based on the Gerstner, or Rankine, model where particles of water describe circular or elliptical stationary orbits. The model can easily produce realistic waves shapes which are varied according to the parameters of the orbits. The surface of the ocean floor affects the refraction and the breaking of waves on the shore. The model can also determine the position, direction, and speed of breakers.The ocean surface is modeled as a parametric surface, permitting the use of traditional rendering methods, including ray-tracing and adaptive subdivision. Animation is easy, since time is built into the model. The foam generated by the breakers is modeled by particle systems whose direction, speed and life expectancy is given by the surface model.To give designers control over the shape of the ocean, the model of the overall surface includes multiple trains of waves, each with its own set of parameters and optional stochastic elements. The overall "randomness" and "short-crestedness" of the ocean is achieved by a combination of small variations within a train and large variations between trains.Rendered examples of oceans waves generated by the model are given and a 10 second animation is described.
{"title":"A simple model of ocean waves","authors":"A. Fournier, W. Reeves","doi":"10.1145/15922.15894","DOIUrl":"https://doi.org/10.1145/15922.15894","url":null,"abstract":"We present a simple model for the surface of the ocean, suitable for the modeling and rendering of most common waves where the disturbing force is from the wind and the restoring force from gravity.It is based on the Gerstner, or Rankine, model where particles of water describe circular or elliptical stationary orbits. The model can easily produce realistic waves shapes which are varied according to the parameters of the orbits. The surface of the ocean floor affects the refraction and the breaking of waves on the shore. The model can also determine the position, direction, and speed of breakers.The ocean surface is modeled as a parametric surface, permitting the use of traditional rendering methods, including ray-tracing and adaptive subdivision. Animation is easy, since time is built into the model. The foam generated by the breakers is modeled by particle systems whose direction, speed and life expectancy is given by the surface model.To give designers control over the shape of the ocean, the model of the overall surface includes multiple trains of waves, each with its own set of parameters and optional stochastic elements. The overall \"randomness\" and \"short-crestedness\" of the ocean is achieved by a combination of small variations within a train and large variations between trains.Rendered examples of oceans waves generated by the model are given and a 10 second animation is described.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84972508","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 new algorithm for ray tracing parametric surface patches is presented. The method uses quasi-Newton iteration to solve for the ray/surface intersection and utilizes ray-to-ray coherence by using numerical information from adjoining rays as initial approximations to the quasi-Newton algorithm. Techniques based upon object space subdivision are used to insure convergence to the correct interesection point. Examples are given of the use of the algorithm in scenes containing Bézier surface patches. Results show that a significant number of ray/surface intersections on these parametric surface patches can be found using very few iterations, giving a significant computational savings.
{"title":"Ray tracing parametric surface patches utilizing numerical techniques and ray coherence","authors":"K. Joy, M. Bhetanabhotla","doi":"10.1145/15922.15917","DOIUrl":"https://doi.org/10.1145/15922.15917","url":null,"abstract":"A new algorithm for ray tracing parametric surface patches is presented. The method uses quasi-Newton iteration to solve for the ray/surface intersection and utilizes ray-to-ray coherence by using numerical information from adjoining rays as initial approximations to the quasi-Newton algorithm. Techniques based upon object space subdivision are used to insure convergence to the correct interesection point. Examples are given of the use of the algorithm in scenes containing Bézier surface patches. Results show that a significant number of ray/surface intersections on these parametric surface patches can be found using very few iterations, giving a significant computational savings.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76417155","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 system of computer programs has been established to generate high quality montage image of considerable usefulness in architectural simulation which combine computer-generated images and photographed background pictures.Traditionally, there are two methods of creating architectural montages: (1) an artist paints new buildings onto a background scene usually generated photographically, and (2) a three-dimensional scale model is created to simulate the whole landscape, and this model is then photographed. The montage method described here combines aspects of both traditional montage methods with significant improvement in accuracy and reduction of time and cost of preparation. Specifically, a digitized photograph is used as a background scene onto which is superimposed a 3D computer-generated image of a new building. The outstanding points of the new method are:(i) The shading and shadows of each computer generated image are calculated with higher accuracy, (ii) the fog effect is taken into account, and (iii) a new anti-aliasing technique improves the quality of the final montage image.
{"title":"A montage method: the overlaying of the computer generated images onto a background photograph","authors":"E. Nakamae, K. Harada, T. Ishizaki, T. Nishita","doi":"10.1145/15922.15909","DOIUrl":"https://doi.org/10.1145/15922.15909","url":null,"abstract":"A system of computer programs has been established to generate high quality montage image of considerable usefulness in architectural simulation which combine computer-generated images and photographed background pictures.Traditionally, there are two methods of creating architectural montages: (1) an artist paints new buildings onto a background scene usually generated photographically, and (2) a three-dimensional scale model is created to simulate the whole landscape, and this model is then photographed. The montage method described here combines aspects of both traditional montage methods with significant improvement in accuracy and reduction of time and cost of preparation. Specifically, a digitized photograph is used as a background scene onto which is superimposed a 3D computer-generated image of a new building. The outstanding points of the new method are:(i) The shading and shadows of each computer generated image are calculated with higher accuracy, (ii) the fog effect is taken into account, and (iii) a new anti-aliasing technique improves the quality of the final montage image.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76522932","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 techniques for improving the performance of image rendering on personal workstations by using CPU cycles going idle while the user is examining a static image on the screen. In that spirit, we believe that a renderer's work is never done. Our goal is to convey the most information to the user as early as possible, with image quality constantly improving with time. We do this by first generating a crude image rapidly and then adaptively refining it where necessary as long as the user does not change viewing parameters. The renderer operates in a succession of phases, first displaying only vertices of polygons, next polygon edges, then flat shading polygons, then shadowing polygons, then Gouraud shading polygons, then Phong shading polygons, and finally anti-aliasing. Performance is enhanced by each phase using results from previous phases and trimming the amount of data needed by the next phase. In this way, only a fraction of the pixels in an image may be Phong shaded while the rest may be Gouraud or flat shaded. Similarly anti-aliasing is performed only on pixels around which there is significant color change. The system features fast response to user intervention, encourages user intervention at any moment, and makes useful the idle cycles in a personal computer.
{"title":"Image rendering by adaptive refinement","authors":"L. Bergman, H. Fuchs, E. Grant, S. Spach","doi":"10.1145/15922.15889","DOIUrl":"https://doi.org/10.1145/15922.15889","url":null,"abstract":"This paper describes techniques for improving the performance of image rendering on personal workstations by using CPU cycles going idle while the user is examining a static image on the screen. In that spirit, we believe that a renderer's work is never done. Our goal is to convey the most information to the user as early as possible, with image quality constantly improving with time. We do this by first generating a crude image rapidly and then adaptively refining it where necessary as long as the user does not change viewing parameters. The renderer operates in a succession of phases, first displaying only vertices of polygons, next polygon edges, then flat shading polygons, then shadowing polygons, then Gouraud shading polygons, then Phong shading polygons, and finally anti-aliasing. Performance is enhanced by each phase using results from previous phases and trimming the amount of data needed by the next phase. In this way, only a fraction of the pixels in an image may be Phong shaded while the rest may be Gouraud or flat shaded. Similarly anti-aliasing is performed only on pixels around which there is significant color change. The system features fast response to user intervention, encourages user intervention at any moment, and makes useful the idle cycles in a personal computer.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86115267","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 are interested in the problem of making precise line drawings using interactive computer graphics. In precise line drawings, specific relationships are expected to hold between points and lines. In published interactive drawing systems, precise relationships have been achieved by using rectangular grids or by solving simultaneous equations (constraints). The availability of fast display hardware and plentiful computational power suggest that we should take another look at the ruler and compass techniques traditionally used by draftsmen. Snap-dragging uses the ruler and compass metaphor to help the user place his next point with precision, and uses heuristics to automatically place guiding lines and circles that are likely to help the user construct each shape. Snap-dragging also provides translation, rotation, and scaling operations that take advantage of the precision placement capability. We show that snap-dragging compares favorably in power and ease of use with grid or constraint techniques.
{"title":"Snap-dragging","authors":"E. Bier, M. Stone","doi":"10.1145/15922.15912","DOIUrl":"https://doi.org/10.1145/15922.15912","url":null,"abstract":"We are interested in the problem of making precise line drawings using interactive computer graphics. In precise line drawings, specific relationships are expected to hold between points and lines. In published interactive drawing systems, precise relationships have been achieved by using rectangular grids or by solving simultaneous equations (constraints). The availability of fast display hardware and plentiful computational power suggest that we should take another look at the ruler and compass techniques traditionally used by draftsmen. Snap-dragging uses the ruler and compass metaphor to help the user place his next point with precision, and uses heuristics to automatically place guiding lines and circles that are likely to help the user construct each shape. Snap-dragging also provides translation, rotation, and scaling operations that take advantage of the precision placement capability. We show that snap-dragging compares favorably in power and ease of use with grid or constraint techniques.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85068533","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 present an integral equation which generalizes a variety of known rendering algorithms. In the course of discussing a monte carlo solution we also present a new form of variance reduction, called Hierarchical sampling and give a number of elaborations shows that it may be an efficient new technique for a wide variety of monte carlo procedures. The resulting rendering algorithm extends the range of optical phenomena which can be effectively simulated.
{"title":"The rendering equation","authors":"J. Kajiya","doi":"10.1145/15922.15902","DOIUrl":"https://doi.org/10.1145/15922.15902","url":null,"abstract":"We present an integral equation which generalizes a variety of known rendering algorithms. In the course of discussing a monte carlo solution we also present a new form of variance reduction, called Hierarchical sampling and give a number of elaborations shows that it may be an efficient new technique for a wide variety of monte carlo procedures. The resulting rendering algorithm extends the range of optical phenomena which can be effectively simulated.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86608344","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 an adaptive, iterative technique for obtaining texture samples of arbitrary precision when synthesizing a computer-generated image. The technique is an improvement on the sum table texturing method. To motivate the technique we analyze the error properties of the sum-table method. Based on that analysis we propose using a combination of tables independently or together to obtain a better estimate, and analyze the error properties of such methods. We then propose a new technique for obtaining texture samples whose accuracy is a function of the texture and the image. As part of this technique we propose the use of an auxiliary table which contains local estimates of the texture variance. We show how the iteration of a given sample may be controlled by values from this table. We then analyze the error in this method, and present images which demonstrate the improvement.
{"title":"Adaptive precision in texture mapping","authors":"A. Glassner","doi":"10.1145/15922.15919","DOIUrl":"https://doi.org/10.1145/15922.15919","url":null,"abstract":"We introduce an adaptive, iterative technique for obtaining texture samples of arbitrary precision when synthesizing a computer-generated image. The technique is an improvement on the sum table texturing method. To motivate the technique we analyze the error properties of the sum-table method. Based on that analysis we propose using a combination of tables independently or together to obtain a better estimate, and analyze the error properties of such methods. We then propose a new technique for obtaining texture samples whose accuracy is a function of the texture and the image. As part of this technique we propose the use of an auxiliary table which contains local estimates of the texture variance. We show how the iteration of a given sample may be controlled by values from this table. We then analyze the error in this method, and present images which demonstrate the improvement.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82161629","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 George Washington User Interface Management System (GWUIMS) has been designed as a test bed for comparing user interface models, as a tool for rapidly prototyping highly interactive graphic user interfaces, and as a vehicle for investigating the applicability of knowledge-based technology to user interface design. The GWUIMS was designed and implemented using the object-oriented programming paradigm and consists of a variety of object classes representing different levels of abstraction, Responsibility for lexical, syntactic, and semantic levels of both input parsing and feedback are distributed throughout these classes. We include a description of the GWUIMS and a brief scenario to demonstrate its capabilities. A description of the implementation is followed by a discussion of the future application of knowledge representation techniques and the evolution towards an intelligent assistant for the user interface designer.
{"title":"An object-oriented user interface management system","authors":"J. Sibert, W. D. Hurley, T. Bleser","doi":"10.1145/15922.15915","DOIUrl":"https://doi.org/10.1145/15922.15915","url":null,"abstract":"The George Washington User Interface Management System (GWUIMS) has been designed as a test bed for comparing user interface models, as a tool for rapidly prototyping highly interactive graphic user interfaces, and as a vehicle for investigating the applicability of knowledge-based technology to user interface design. The GWUIMS was designed and implemented using the object-oriented programming paradigm and consists of a variety of object classes representing different levels of abstraction, Responsibility for lexical, syntactic, and semantic levels of both input parsing and feedback are distributed throughout these classes. We include a description of the GWUIMS and a brief scenario to demonstrate its capabilities. A description of the implementation is followed by a discussion of the future application of knowledge representation techniques and the evolution towards an intelligent assistant for the user interface designer.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85697955","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 goal of science is to understand why things are the way they are. By emulating the logic of nature, computer simulation programs capture the essence of natural objects, thereby serving as a tool of science. When these programs express this essence visually, they serve as an instrument of art as well.This paper presents a fractal computer model of branching objects. This program generates pictures of simple orderly plants, complex gnarled trees, leaves, vein systems, as well as inorganic structures such as river deltas, snow flakes, etc. The geometry and topology of the model are controlled by numerical parameters which are analogous to the organism's DNA. By manipulating the genetic parameters, one can modify the geometry of the object in real time, using tree based graphics hardware. The random effects of the environment are taken into account, to produce greater diversity and realism. Increasing the number of significant parameters yields more complex and evolved species.The program provides a study in the structure of branching objects that is both scientific and artistic. The results suggest that organisms and computers deal with complexity in similar ways.
{"title":"Real time design and animation of fractal plants and trees","authors":"P. Oppenheimer","doi":"10.1145/15922.15892","DOIUrl":"https://doi.org/10.1145/15922.15892","url":null,"abstract":"The goal of science is to understand why things are the way they are. By emulating the logic of nature, computer simulation programs capture the essence of natural objects, thereby serving as a tool of science. When these programs express this essence visually, they serve as an instrument of art as well.This paper presents a fractal computer model of branching objects. This program generates pictures of simple orderly plants, complex gnarled trees, leaves, vein systems, as well as inorganic structures such as river deltas, snow flakes, etc. The geometry and topology of the model are controlled by numerical parameters which are analogous to the organism's DNA. By manipulating the genetic parameters, one can modify the geometry of the object in real time, using tree based graphics hardware. The random effects of the environment are taken into account, to produce greater diversity and realism. Increasing the number of significant parameters yields more complex and evolved species.The program provides a study in the structure of branching objects that is both scientific and artistic. The results suggest that organisms and computers deal with complexity in similar ways.","PeriodicalId":20524,"journal":{"name":"Proceedings of the 13th annual conference on Computer graphics and interactive techniques","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79557508","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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