In this paper we identify sources of error in global illumination algorithms and derive bounds for each distinct category. Errors arise from three sources: inaccuracies in the boundary data, discretization, and computation. Boundary data consists of surface geometry, reflectance functions, and emission functions, all of which may be perturbed by errors in measurement or simulation, or by simplifications made for computational efficiency. Discretization error is introduced by replacing the continuous radiative transfer equation with a finite-dimensional linear system, usually by means of boundary elements and a corresponding projection method. Finally, computational errors perturb the finite-dimensional linear system through imprecise form factors, inner products, visibility, etc., as well as by halting iterative solvers after a finite number of steps. Using the error taxonomy introduced in the paper we examine existing global illumination algorithms and suggest new avenues of research.
{"title":"A framework for the analysis of error in global illumination algorithms","authors":"J. Arvo, K. Torrance, Brian E. Smits","doi":"10.1145/192161.192179","DOIUrl":"https://doi.org/10.1145/192161.192179","url":null,"abstract":"In this paper we identify sources of error in global illumination algorithms and derive bounds for each distinct category. Errors arise from three sources: inaccuracies in the boundary data, discretization, and computation. Boundary data consists of surface geometry, reflectance functions, and emission functions, all of which may be perturbed by errors in measurement or simulation, or by simplifications made for computational efficiency. Discretization error is introduced by replacing the continuous radiative transfer equation with a finite-dimensional linear system, usually by means of boundary elements and a corresponding projection method. Finally, computational errors perturb the finite-dimensional linear system through imprecise form factors, inner products, visibility, etc., as well as by halting iterative solvers after a finite number of steps. Using the error taxonomy introduced in the paper we examine existing global illumination algorithms and suggest new avenues of research.","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115418397","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}
Hugues Hoppe, T. DeRose, T. Duchamp, Mark A. Halstead, H. Jin, J. McDonald, Jean Schweitzer, W. Stuetzle
We present a general method for automatic reconstruction of accurate, concise, piecewise smooth surface models from scattered range data. The method can be used in a variety of applications such as reverse engineering—the automatic generation of CAD models from physical objects. Novel aspects of the method are its ability to model surfaces of arbitrary topological type and to recover sharp features such as creases and corners. The method has proven to be effective, as demonstrated by a number of examples using both simulated and real data. A key ingredient in the method, and a principal contribution of this paper, is the introduction of a new class of piecewise smooth surface representations based on subdivision. These surfaces have a number of properties that make them ideal for use in surface reconstruction: they are simple to implement, they can model sharp features concisely, and they can be fit to scattered range data using an unconstrained optimization procedure.
{"title":"Piecewise smooth surface reconstruction","authors":"Hugues Hoppe, T. DeRose, T. Duchamp, Mark A. Halstead, H. Jin, J. McDonald, Jean Schweitzer, W. Stuetzle","doi":"10.1145/192161.192233","DOIUrl":"https://doi.org/10.1145/192161.192233","url":null,"abstract":"We present a general method for automatic reconstruction of accurate, concise, piecewise smooth surface models from scattered range data. The method can be used in a variety of applications such as reverse engineering—the automatic generation of CAD models from physical objects. Novel aspects of the method are its ability to model surfaces of arbitrary topological type and to recover sharp features such as creases and corners. The method has proven to be effective, as demonstrated by a number of examples using both simulated and real data. A key ingredient in the method, and a principal contribution of this paper, is the introduction of a new class of piecewise smooth surface representations based on subdivision. These surfaces have a number of properties that make them ideal for use in surface reconstruction: they are simple to implement, they can model sharp features concisely, and they can be fit to scattered range data using an unconstrained optimization procedure.","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125176136","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}
J. Marks, Michael F. Cohen, J. Ngo, S. Shieber, John M. Snyder
practitioner in computer graphics was a solid background in geometry, algebra, calculus, topology, probability, mechanics, electromagnetism, signal processing, image processing, electrical engineering, mechanical engineering, optics, information theory, structured programming, basic algorithms and data structures, complexity theory, computer architecture, human factors, perceptual psychology, colorimetry, graphic design, industrial design, semiotics, and art! Unfortunately, the list is growing, and one more topic can now be included: optimization. A perusal of the computer-graphics literature reveals a recent trend towards using optimization to solve problems in image rendering, object modeling, animation, and even chart graphics. The techniques used run the gamut from standard function-optimization algorithms that have their roots in continuous mathematics [10], to black-art stochastic techniques that are inspired by natural processes like evolution and annealing [2]. The participants in the panel reflect this diversity in problem domain and optimization approach. Each panelist will list problems in his areas of expertise for which optimization techniques have proven effective, describe the optimization methods that have been most successful for these problems, present a representative example from the panelist’s own research of an optimization problem and method, attempt to predict the future impact of optimization on computer graphics, and suggest how engineers and artists might apply optimization techniques to practical problems.
{"title":"Optimization—an emerging tool in computer graphics","authors":"J. Marks, Michael F. Cohen, J. Ngo, S. Shieber, John M. Snyder","doi":"10.1145/192161.192294","DOIUrl":"https://doi.org/10.1145/192161.192294","url":null,"abstract":"practitioner in computer graphics was a solid background in geometry, algebra, calculus, topology, probability, mechanics, electromagnetism, signal processing, image processing, electrical engineering, mechanical engineering, optics, information theory, structured programming, basic algorithms and data structures, complexity theory, computer architecture, human factors, perceptual psychology, colorimetry, graphic design, industrial design, semiotics, and art! Unfortunately, the list is growing, and one more topic can now be included: optimization. A perusal of the computer-graphics literature reveals a recent trend towards using optimization to solve problems in image rendering, object modeling, animation, and even chart graphics. The techniques used run the gamut from standard function-optimization algorithms that have their roots in continuous mathematics [10], to black-art stochastic techniques that are inspired by natural processes like evolution and annealing [2]. The participants in the panel reflect this diversity in problem domain and optimization approach. Each panelist will list problems in his areas of expertise for which optimization techniques have proven effective, describe the optimization methods that have been most successful for these problems, present a representative example from the panelist’s own research of an optimization problem and method, attempt to predict the future impact of optimization on computer graphics, and suggest how engineers and artists might apply optimization techniques to practical problems.","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129771941","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}
Surface reflections of an environment can be rendered in real time if hardware calculates an unnormalized reflection vector at each pixel. Conventional perspective-correct texture hardware can then be leveraged to draw high-quality reflections of an environment or specular highlights in real time. This fully accommodates area light sources, allows a local viewer to move interactively, and is especially well suited to the inspection of surface orientation and curvature. By emphasizing the richness of the incoming illumination rather than physical surface properties, it represents a new direction for real-time shading hardware.
{"title":"Reflection vector shading hardware","authors":"D. Voorhies, Jim Foran","doi":"10.1145/192161.192193","DOIUrl":"https://doi.org/10.1145/192161.192193","url":null,"abstract":"Surface reflections of an environment can be rendered in real time if hardware calculates an unnormalized reflection vector at each pixel. Conventional perspective-correct texture hardware can then be leveraged to draw high-quality reflections of an environment or specular highlights in real time. This fully accommodates area light sources, allows a local viewer to move interactively, and is especially well suited to the inspection of surface orientation and curvature. By emphasizing the richness of the incoming illumination rather than physical surface properties, it represents a new direction for real-time shading hardware.","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128475220","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 irradiance at a point on a surface due to a polyhedral source of uniform brightness is given by a well-known analytic formula. In this paper we derive the corresponding analytic expression for the irradiance Jacobian, the derivative of the vector representation of irradiance. Although the result is elementary for unoccluded sources, within penumbrae the irradiance Jacobian must incorporate more information about blockers than either the irradiance or vector irradiance. The expression presented here holds for any number of polyhedral blockers and requires only a minor extension of standard polygon clipping to evaluate. To illustrate its use, three related applications are briefing described: direct computation of isolux contours, finding local irradiance extrema, and iso-meshing. Isolux contours are curves of constant irradiance across a surface that can be followed using a predictor-corrector method based on the irradiance Jacobian. Similarly, local extrema can be found using a descent method. Finally, iso-meshing is a new approach to surface mesh generation that incorporates families of isolux contours.
{"title":"The irradiance Jacobian for partially occluded polyhedral sources","authors":"J. Arvo","doi":"10.1145/192161.192250","DOIUrl":"https://doi.org/10.1145/192161.192250","url":null,"abstract":"The irradiance at a point on a surface due to a polyhedral source of uniform brightness is given by a well-known analytic formula. In this paper we derive the corresponding analytic expression for the irradiance Jacobian, the derivative of the vector representation of irradiance. Although the result is elementary for unoccluded sources, within penumbrae the irradiance Jacobian must incorporate more information about blockers than either the irradiance or vector irradiance. The expression presented here holds for any number of polyhedral blockers and requires only a minor extension of standard polygon clipping to evaluate. To illustrate its use, three related applications are briefing described: direct computation of isolux contours, finding local irradiance extrema, and iso-meshing. Isolux contours are curves of constant irradiance across a surface that can be followed using a predictor-corrector method based on the irradiance Jacobian. Similarly, local extrema can be found using a descent method. Finally, iso-meshing is a new approach to surface mesh generation that incorporates families of isolux contours.","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"16 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126668688","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 proposes a framework for animation that can achieve the intricacy of motion evident in certain natural ecosystems with minimal input from the animator. The realistic appearance, movement, and behavior of individual animals, as well as the patterns of behavior evident in groups of animals fall within the scope of the framework. Our approach to emulating this level of natural complexity is to model each animal holistically as an autonomous agent situated in its physical world. To demonstrate the approach, we develop a physics-based, virtual marine world. The world is inhabited by artificial fishes that can swim hydrodynamically in simulated water through the motor control of internal muscles that motivates fins. Their repertoire of behaviors relies on their perception of the dynamic environment. As in nature, the detailed motions of artificial fishes in their virtual habitat are not entirely predictable because they are not scripted.
{"title":"Artificial fishes: physics, locomotion, perception, behavior","authors":"Xiaoyuan Tu, Demetri Terzopoulos","doi":"10.1145/192161.192170","DOIUrl":"https://doi.org/10.1145/192161.192170","url":null,"abstract":"This paper proposes a framework for animation that can achieve the intricacy of motion evident in certain natural ecosystems with minimal input from the animator. The realistic appearance, movement, and behavior of individual animals, as well as the patterns of behavior evident in groups of animals fall within the scope of the framework. Our approach to emulating this level of natural complexity is to model each animal holistically as an autonomous agent situated in its physical world. To demonstrate the approach, we develop a physics-based, virtual marine world. The world is inhabited by artificial fishes that can swim hydrodynamically in simulated water through the motor control of internal muscles that motivates fins. Their repertoire of behaviors relies on their perception of the dynamic environment. As in nature, the detailed motions of artificial fishes in their virtual habitat are not entirely predictable because they are not scripted.","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121430679","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}
T. Rhyne, George H. Brett, D. Brutzman, D. Cox, Adelino Santos
and collaboration using high speed networking, multimedia and interactive computer graphics techniques. Efforts among researchers, programmers, and artists (i.e. Renissance Teams) to use the new National Information Infrastructure (NII) as well as international telecommunication systems are featured. Software tools which support collaborative visualization across heterogenous platforms for research, education and commerical purposes are highlighted. Collaborative computing involves facilitating information discovery and scientific visualization activities between researchers located at various remote sites. It includes the use of visualization and information retrieval in a high speed networked environment. Computing resources become transparently available to researchers via the networked environment and this results in a metacomputer. Some collaborations involve interdisciplinary teams focused on solving a single problem while others encompass the sharing of different methodologies and resulting solutions to similar problems. Positive aspects associated with these high speed networked collaborations center on real time visualization and information discovery among geographically remote research or Renaissance Teams. There are also negative impacts or roadblocks associated with metacomputing. Network transmission difficulties and differences in desktop workstation architectures can cloud the actual visualization two collaborating researchers are simultaneously viewing and steering. Setting up and learning to use the metacomputing infrastructure can be all consuming and thus refocus the basic education or scientific discovery process. Various perspectives on these concerns are debated by the panelists.
{"title":"Exploiting networks for visualization and collaboration: no network roadblocks?","authors":"T. Rhyne, George H. Brett, D. Brutzman, D. Cox, Adelino Santos","doi":"10.1145/192161.192292","DOIUrl":"https://doi.org/10.1145/192161.192292","url":null,"abstract":"and collaboration using high speed networking, multimedia and interactive computer graphics techniques. Efforts among researchers, programmers, and artists (i.e. Renissance Teams) to use the new National Information Infrastructure (NII) as well as international telecommunication systems are featured. Software tools which support collaborative visualization across heterogenous platforms for research, education and commerical purposes are highlighted. Collaborative computing involves facilitating information discovery and scientific visualization activities between researchers located at various remote sites. It includes the use of visualization and information retrieval in a high speed networked environment. Computing resources become transparently available to researchers via the networked environment and this results in a metacomputer. Some collaborations involve interdisciplinary teams focused on solving a single problem while others encompass the sharing of different methodologies and resulting solutions to similar problems. Positive aspects associated with these high speed networked collaborations center on real time visualization and information discovery among geographically remote research or Renaissance Teams. There are also negative impacts or roadblocks associated with metacomputing. Network transmission difficulties and differences in desktop workstation architectures can cloud the actual visualization two collaborating researchers are simultaneously viewing and steering. Setting up and learning to use the metacomputing infrastructure can be all consuming and thus refocus the basic education or scientific discovery process. Various perspectives on these concerns are debated by the panelists.","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126262838","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. R. Mitchell, Stuart Rosen, W. Bricken, Ron Martinez, B. Laurel
Psychological immersivity is the most important performance measure of effectiveness for media experiences, from watching a computer generated animation to having an interactive experience in a virtual reality (VR) environment. To offer and foster the best value hardware systems and the most effecive software media, we need to know what determines immersivity: realistic graphics, realistic action , or some sort of balance? The panel will address this critical question with presentations by five experts with varied points of view. The four key concepts of the panel are Psychological Immersivity, VR, Realistic Action, and Realistic Graphics. Psychological Immersivity is a process in which many of a person’s senses are stimulated by an artificial environment, to the point where emotions and intellect follow as though actually in a real-world or other-world event. VR is a computer generated, real time, interactive environment of three-dimensional visual, aural, and other sensed phenomena. Realistic action refers to both the quality of a VR story line or adventure scenario and the fidelity of its dynamic realization, including attributes such as motion, voice generation or recongnition, and virtual character behavior. Realistic graphics refers to visual fidelity attributes, such as resolution, field of view, frame rate, polygon density, and texture map complexity. The psychologist Mihaly Csikszentmihalyi, writing about years of research into what causes happiness in life’s experiences, has identified a state called “flow.” Flow is a process characteristic of certain human activities that is akin to what we call psychological immersion for VR experiences. This research supports the contention that psychological immersivity is the most important measure of merit and that interactivity is critical for optimized consumer happiness. But the work does not answer the basic question of whether realistic graphics or realistic action is the greater determinant of immersivity. The location-based and home entertainment industries are becoming aware that distributed interactive simulation systems developed for Army training (SimNet and Close Combat Tactical Trainer) indicate that VR envrironments can produce a greater depth of immersivity than any other simulation training experience. That evidence from military training is reinforced by reports from consumers of newly emerging location-based and home entertainment VR products. But why is that so? VR graphics are usually inferior to animations due to the need for real time rendering. We also note that VR action can offer a higher level of interactivity because of the four-dimensional, space-time degrees of freedom. Does this mean that realistic action is more important than realistic graphics? Designers of networked, interactive computer games (MUDs) generally believe that action is much more important than graphics. Players of these text-based adventure games have hours of immersivity. Is this more evidence that
{"title":"Determinants of immersivity in virtual reality: graphics vs. action","authors":"A. R. Mitchell, Stuart Rosen, W. Bricken, Ron Martinez, B. Laurel","doi":"10.1145/192161.192303","DOIUrl":"https://doi.org/10.1145/192161.192303","url":null,"abstract":"Psychological immersivity is the most important performance measure of effectiveness for media experiences, from watching a computer generated animation to having an interactive experience in a virtual reality (VR) environment. To offer and foster the best value hardware systems and the most effecive software media, we need to know what determines immersivity: realistic graphics, realistic action , or some sort of balance? The panel will address this critical question with presentations by five experts with varied points of view. The four key concepts of the panel are Psychological Immersivity, VR, Realistic Action, and Realistic Graphics. Psychological Immersivity is a process in which many of a person’s senses are stimulated by an artificial environment, to the point where emotions and intellect follow as though actually in a real-world or other-world event. VR is a computer generated, real time, interactive environment of three-dimensional visual, aural, and other sensed phenomena. Realistic action refers to both the quality of a VR story line or adventure scenario and the fidelity of its dynamic realization, including attributes such as motion, voice generation or recongnition, and virtual character behavior. Realistic graphics refers to visual fidelity attributes, such as resolution, field of view, frame rate, polygon density, and texture map complexity. The psychologist Mihaly Csikszentmihalyi, writing about years of research into what causes happiness in life’s experiences, has identified a state called “flow.” Flow is a process characteristic of certain human activities that is akin to what we call psychological immersion for VR experiences. This research supports the contention that psychological immersivity is the most important measure of merit and that interactivity is critical for optimized consumer happiness. But the work does not answer the basic question of whether realistic graphics or realistic action is the greater determinant of immersivity. The location-based and home entertainment industries are becoming aware that distributed interactive simulation systems developed for Army training (SimNet and Close Combat Tactical Trainer) indicate that VR envrironments can produce a greater depth of immersivity than any other simulation training experience. That evidence from military training is reinforced by reports from consumers of newly emerging location-based and home entertainment VR products. But why is that so? VR graphics are usually inferior to animations due to the need for real time rendering. We also note that VR action can offer a higher level of interactivity because of the four-dimensional, space-time degrees of freedom. Does this mean that realistic action is more important than realistic graphics? Designers of networked, interactive computer games (MUDs) generally believe that action is much more important than graphics. Players of these text-based adventure games have hours of immersivity. Is this more evidence that ","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115865561","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 considers an idealized subclass of surface reflectivities; namely a simple superposition of ideal diffuse and ideal specular, restricted to point light sources. The paper derives a model of diffuse and specular illumination in arbitrarily large dimensions, based on a few characteristics of material and light in 3-space. It describes how to adjust for the anomaly of excess brightness in large codimensions. If a surface is grooved or furry, it can be illuminated with a hybrid model that incorporates both the ID geometry (the grooves or fur) and the 2D geometry (the surface).
{"title":"Illumination in diverse codimensions","authors":"D. Banks","doi":"10.1145/192161.192246","DOIUrl":"https://doi.org/10.1145/192161.192246","url":null,"abstract":"This paper considers an idealized subclass of surface reflectivities; namely a simple superposition of ideal diffuse and ideal specular, restricted to point light sources. The paper derives a model of diffuse and specular illumination in arbitrarily large dimensions, based on a few characteristics of material and light in 3-space. It describes how to adjust for the anomaly of excess brightness in large codimensions. If a surface is grooved or furry, it can be illuminated with a hybrid model that incorporates both the ID geometry (the grooves or fur) and the 2D geometry (the surface).","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130713697","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 novel system for creating virtual creatures that move and behave in simulated three-dimensional physical worlds. The morphologies of creatures and the neural systems for controlling their muscle forces are both generated automatically using genetic algorithms. Different fitness evaluation functions are used to direct simulated evolutions towards specific behaviors such as swimming, walking, jumping, and following. A genetic language is presented that uses nodes and connections as its primitive elements to represent directed graphs, which are used to describe both the morphology and the neural circuitry of these creatures. This genetic language defines a hyperspace containing an indefinite number of possible creatures with behaviors, and when it is searched using optimization techniques, a variety of successful and interesting locomotion strategies emerge, some of which would be difficult to invent or built by design.
{"title":"Evolving virtual creatures","authors":"Karl Sims","doi":"10.1145/192161.192167","DOIUrl":"https://doi.org/10.1145/192161.192167","url":null,"abstract":"This paper describes a novel system for creating virtual creatures that move and behave in simulated three-dimensional physical worlds. The morphologies of creatures and the neural systems for controlling their muscle forces are both generated automatically using genetic algorithms. Different fitness evaluation functions are used to direct simulated evolutions towards specific behaviors such as swimming, walking, jumping, and following. A genetic language is presented that uses nodes and connections as its primitive elements to represent directed graphs, which are used to describe both the morphology and the neural circuitry of these creatures. This genetic language defines a hyperspace containing an indefinite number of possible creatures with behaviors, and when it is searched using optimization techniques, a variety of successful and interesting locomotion strategies emerge, some of which would be difficult to invent or built by design.","PeriodicalId":151245,"journal":{"name":"Proceedings of the 21st annual conference on Computer graphics and interactive techniques","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123957755","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：