Metamouse is a device enabling the user of a drawing program to specify graphical procedures by supplying example execution traces. The user manipulates objects directly on the screen, creating graphical tools where necessary to help make constraints explicit; the system records the sequence of actions and induces a procedure. Generalization is used both to identify the key features of individual program steps, disregarding coincidental events; and to connect the steps into a program graph, creating loops and conditional branches as appropriate. Metamouse operates within a 2D click-and-drag drafting package, and incorporates a strong model of the relative importance of different types of graphical constraint. Close attention is paid to user interface aspects, and Metamouse helps the user by predicting and performing actions, thus reducing the tedium of repetitive graphical editing tasks.
{"title":"Metamouse: specifying graphical procedures by example","authors":"D. Maulsby, I. Witten, Kenneth A. Kittlitz","doi":"10.1145/74333.74346","DOIUrl":"https://doi.org/10.1145/74333.74346","url":null,"abstract":"Metamouse is a device enabling the user of a drawing program to specify graphical procedures by supplying example execution traces. The user manipulates objects directly on the screen, creating graphical tools where necessary to help make constraints explicit; the system records the sequence of actions and induces a procedure. Generalization is used both to identify the key features of individual program steps, disregarding coincidental events; and to connect the steps into a program graph, creating loops and conditional branches as appropriate. Metamouse operates within a 2D click-and-drag drafting package, and incorporates a strong model of the relative importance of different types of graphical constraint. Close attention is paid to user interface aspects, and Metamouse helps the user by predicting and performing actions, thus reducing the tedium of repetitive graphical editing tasks.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116858978","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}
Image warping refers to the 2-D resampling of a source image onto a target image. In the general case, this requires costly 2-D filtering operations. Simplifications are possible when the warp can be expressed as a cascade of orthogonal 1-D transformations. In these cases, separable transformations have been introduced to realize large performance gains. The central ideas in this area were formulated in the 2-pass algorithm by Catmull and Smith. Although that method applies over an important class of transformations, there are intrinsic problems which limit its usefulness.The goal of this work is to extend the 2-pass approach to handle arbitrary spatial mapping functions. We address the difficulties intrinsic to 2-pass scanline algorithms: bottlenecking, foldovers, and the lack of closed-form inverse solutions. These problems are shown to be resolved in a general, efficient, separable technique, with graceful degradation for transformations of increasing complexity.
{"title":"Separable image warping with spatial lookup tables","authors":"G. Wolberg, T. Boult","doi":"10.1145/74333.74371","DOIUrl":"https://doi.org/10.1145/74333.74371","url":null,"abstract":"Image warping refers to the 2-D resampling of a source image onto a target image. In the general case, this requires costly 2-D filtering operations. Simplifications are possible when the warp can be expressed as a cascade of orthogonal 1-D transformations. In these cases, separable transformations have been introduced to realize large performance gains. The central ideas in this area were formulated in the 2-pass algorithm by Catmull and Smith. Although that method applies over an important class of transformations, there are intrinsic problems which limit its usefulness.The goal of this work is to extend the 2-pass approach to handle arbitrary spatial mapping functions. We address the difficulties intrinsic to 2-pass scanline algorithms: bottlenecking, foldovers, and the lack of closed-form inverse solutions. These problems are shown to be resolved in a general, efficient, separable technique, with graceful degradation for transformations of increasing complexity.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123583154","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 concerned in this paper with associations between spline curves that will hold at all inbetween positions when the control points of these curves are used as key points for animation or sweeping. It is established that any association between two spline curves that can be expressed as the equality of two linear mappings will hold throughout an inbetweening process provided the inbetweening trajectories are coordinated splines that uniquely interpolate the control-point key positions. Multiple associations are possible, so long as the basic requirements of linearity and coordination are observed.
{"title":"Curve-to-curve associations in spline-based inbetweening and sweeping","authors":"R. Bartels, Ronald T. Hardock","doi":"10.1145/74333.74350","DOIUrl":"https://doi.org/10.1145/74333.74350","url":null,"abstract":"We are concerned in this paper with associations between spline curves that will hold at all inbetween positions when the control points of these curves are used as key points for animation or sweeping. It is established that any association between two spline curves that can be expressed as the equality of two linear mappings will hold throughout an inbetweening process provided the inbetweening trajectories are coordinated splines that uniquely interpolate the control-point key positions. Multiple associations are possible, so long as the basic requirements of linearity and coordination are observed.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126423418","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 robust algorithm is presented for scan line display of algebraic surfaces of arbitrary degree and topology. The algorithm correctly displays singularities of any complexity, even those missed by ray tracing or polygonization, and (for surfaces of degree less than eight) offers a significant speed improvement over ray tracing. Antialiasing can generally be accomplished very quickly. In addition to its typical function of shaded raster display, the algorithm is particularly adept at quickly plotting silhouette and intersection curves. A practical use for the algorithm is to display boolean combinations of algebraic half spaces, including blend surfaces.A new polynomial basis is introduced, referred to as the Bernstein pyramid polynomial basis, which enhances numerical stability and which simplifies several computations such as scan planesurface intersection and silhouette detection.
{"title":"Scan line display of algebraic surfaces","authors":"T. Sederberg, A. Zundel","doi":"10.1145/74333.74348","DOIUrl":"https://doi.org/10.1145/74333.74348","url":null,"abstract":"A robust algorithm is presented for scan line display of algebraic surfaces of arbitrary degree and topology. The algorithm correctly displays singularities of any complexity, even those missed by ray tracing or polygonization, and (for surfaces of degree less than eight) offers a significant speed improvement over ray tracing. Antialiasing can generally be accomplished very quickly. In addition to its typical function of shaded raster display, the algorithm is particularly adept at quickly plotting silhouette and intersection curves. A practical use for the algorithm is to display boolean combinations of algebraic half spaces, including blend surfaces.A new polynomial basis is introduced, referred to as the Bernstein pyramid polynomial basis, which enhances numerical stability and which simplifies several computations such as scan planesurface intersection and silhouette detection.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128273710","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}
As shown in 1982, Julia sets of quadratic functions as well as many other deterministic fractals exist in spaces of higher dimensionality than the complex plane. Originally a boundary-tracking algorithm was used to view these structures but required a large amount of storage space to operate. By ray tracing these objects, the storage facilities of a graphics workstation frame buffer are sufficient. A short discussion of a specific set of 3-D deterministic fractals precedes a full description of a ray-tracing algorithm applied to these objects. A comparison with the boundary-tracking method and applications to other 3-D deterministic fractals are also included.
{"title":"Ray tracing deterministic 3-D fractals","authors":"J. Hart, D. Sandin, L. Kauffman","doi":"10.1145/74333.74363","DOIUrl":"https://doi.org/10.1145/74333.74363","url":null,"abstract":"As shown in 1982, Julia sets of quadratic functions as well as many other deterministic fractals exist in spaces of higher dimensionality than the complex plane. Originally a boundary-tracking algorithm was used to view these structures but required a large amount of storage space to operate. By ray tracing these objects, the storage facilities of a graphics workstation frame buffer are sufficient. A short discussion of a specific set of 3-D deterministic fractals precedes a full description of a ray-tracing algorithm applied to these objects. A comparison with the boundary-tracking method and applications to other 3-D deterministic fractals are also included.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130966293","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}
X. Viennot, Georges Eyrolles, N. Janey, Didier Arquds
Herein is presented a new procedural method for generating images of trees. Many other algorithms have already been proposed in the last few years focusing on particle systems, fractals, graftals and L-systems or realistic botanical models. Usually the final visual aspect of the tree depends on the development process leading to this form. Our approach differs from all the previous ones. We begin by defining a certain "measure" of the form of a tree or a branching pattern. This is done by introducing the new concept of ramification matrix of a tree. Then we give an algorithm for generating a random tree having as ramification matrix a given arbitrary stochastic triangular matrix. The geometry of the tree is defined from the combinatorial parameters implied in the analysis of the forms of trees. We obtain a method with powerful control of the final form, simple enough to produce quick designs of trees without loosing in the variety and rendering of the images. We also introduce a new rapid drawing of the leaves. The underlying combinatorics constitute a refinment of some work introduced in hydrogeology in the morphological study of river networks. The concept of ramification matrix has been used very recently in physics in the study of fractal ramified patterns.
{"title":"Combinatorial analysis of ramified patterns and computer imagery of trees","authors":"X. Viennot, Georges Eyrolles, N. Janey, Didier Arquds","doi":"10.1145/74333.74336","DOIUrl":"https://doi.org/10.1145/74333.74336","url":null,"abstract":"Herein is presented a new procedural method for generating images of trees. Many other algorithms have already been proposed in the last few years focusing on particle systems, fractals, graftals and L-systems or realistic botanical models. Usually the final visual aspect of the tree depends on the development process leading to this form. Our approach differs from all the previous ones. We begin by defining a certain \"measure\" of the form of a tree or a branching pattern. This is done by introducing the new concept of ramification matrix of a tree. Then we give an algorithm for generating a random tree having as ramification matrix a given arbitrary stochastic triangular matrix. The geometry of the tree is defined from the combinatorial parameters implied in the analysis of the forms of trees. We obtain a method with powerful control of the final form, simple enough to produce quick designs of trees without loosing in the variety and rendering of the images. We also introduce a new rapid drawing of the leaves. The underlying combinatorics constitute a refinment of some work introduced in hydrogeology in the morphological study of river networks. The concept of ramification matrix has been used very recently in physics in the study of fractal ramified patterns.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121446894","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 solid noise is a function that defines a random value at each point in space. Solid noises have immediate and powerful applications in surface texturing, stochastic modeling, and the animation of natural phenomena.Existing solid noise synthesis algorithms are surveyed and two new algorithms are presented. The first uses Wiener interpolation to interpolate random values on a discrete lattice. The second is an efficient sparse convolution algorithm. Both algorithms are developed for model-directed synthesis, in which sampling and construction of the noise occur only at points where the noise value is required, rather than over a regularly sampled region of space. The paper attempts to present the rationale for the selection of these particular algorithms.The new algorithms have advantages of efficiency, improved control over the noise power spectrum, and the absence of artifacts. The convolution algorithm additionally allows quality to be traded for efficiency without introducing obvious deterministic effects. The algorithms are particularly suitable for applications where high-quality solid noises are required. Several sample applications in stochastic modeling and solid texturing are shown.
{"title":"Algorithms for solid noise synthesis","authors":"J. P. Lewis","doi":"10.1145/74333.74360","DOIUrl":"https://doi.org/10.1145/74333.74360","url":null,"abstract":"A solid noise is a function that defines a random value at each point in space. Solid noises have immediate and powerful applications in surface texturing, stochastic modeling, and the animation of natural phenomena.Existing solid noise synthesis algorithms are surveyed and two new algorithms are presented. The first uses Wiener interpolation to interpolate random values on a discrete lattice. The second is an efficient sparse convolution algorithm. Both algorithms are developed for model-directed synthesis, in which sampling and construction of the noise occur only at points where the noise value is required, rather than over a regularly sampled region of space. The paper attempts to present the rationale for the selection of these particular algorithms.The new algorithms have advantages of efficiency, improved control over the noise power spectrum, and the absence of artifacts. The convolution algorithm additionally allows quality to be traded for efficiency without introducing obvious deterministic effects. The algorithms are particularly suitable for applications where high-quality solid noises are required. Several sample applications in stochastic modeling and solid texturing are shown.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"240 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124635593","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}
Rational tensor product surfaces, (Bézier, NURBS, Hermite, polynomial, etc.) are rendered in real-time by uniform faceting. The described methods are modular and can be balanced for optimal implementation on different hardware platforms. Discretization anomalies such as angularities, Mach banding, cracking etc. are avoided by tessellating the surface patches and segmenting the trimming curves based on the view.
{"title":"Real-time rendering of trimmed surfaces","authors":"A. Rockwood, Kurt Heaton, Tom Davis","doi":"10.1145/74333.74344","DOIUrl":"https://doi.org/10.1145/74333.74344","url":null,"abstract":"Rational tensor product surfaces, (Bézier, NURBS, Hermite, polynomial, etc.) are rendered in real-time by uniform faceting. The described methods are modular and can be balanced for optimal implementation on different hardware platforms. Discretization anomalies such as angularities, Mach banding, cracking etc. are avoided by tessellating the surface patches and segmenting the trimming curves based on the view.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"393 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115915383","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 model phenomena intermediate between shape and texture by using space-filling applicative functions to modulate density. The model is essentially an extension of procedural solid texture synthesis, but evaluated throughout a volumetric region instead of only at surfaces.We have been able to obtain visually realistic representations of such shape+texture (hypertexture) phenomena as hair, fur, fire, glass, fluid flow and erosion effects. We show how this is done, first by describing a set of base level functions to provide basic texture and control capability, then by combining these to synthesize various phenomena.Hypertexture exists within an intermediate region between object and not-object. We introduce a notion of generalized boolean shape operators to combine shapes having such a region.Rendering is accomplished by ray marching from the eye point through the volume to accumulate opacity along each ray. We have implemented our hypertexture rendering algorithms on a traditional serial computer, a distributed network of computers and a coarse-grain MIMD computer. Extensions to the rendering technique incorporating refraction and reflection effects are discussed.
{"title":"Hypertexture","authors":"K. Perlin, Eric M. Hoffert","doi":"10.1145/74333.74359","DOIUrl":"https://doi.org/10.1145/74333.74359","url":null,"abstract":"We model phenomena intermediate between shape and texture by using space-filling applicative functions to modulate density. The model is essentially an extension of procedural solid texture synthesis, but evaluated throughout a volumetric region instead of only at surfaces.We have been able to obtain visually realistic representations of such shape+texture (hypertexture) phenomena as hair, fur, fire, glass, fluid flow and erosion effects. We show how this is done, first by describing a set of base level functions to provide basic texture and control capability, then by combining these to synthesize various phenomena.Hypertexture exists within an intermediate region between object and not-object. We introduce a notion of generalized boolean shape operators to combine shapes having such a region.Rendering is accomplished by ray marching from the eye point through the volume to accumulate opacity along each ray. We have implemented our hypertexture rendering algorithms on a traditional serial computer, a distributed network of computers and a coarse-grain MIMD computer. Extensions to the rendering technique incorporating refraction and reflection effects are discussed.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129150685","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}
N. Gharachorloo, S. Gupta, R. Sproull, I. Sutherland
With widespread use of raster scan displays and the ever-increasing desire for faster interactivity, higher image complexity, and higher resolution in displayed images, several techniques have been proposed for rasterizing primitive graphical objects. This paper characterizes the performance of these techniques and shows how they evolve for more complex images on higher resolution displays. This characterization will not only show the strengths and deficiencies of existing rasterization techniques, but will also reveal new architectures for future raster graphics systems.
{"title":"A characterization of ten rasterization techniques","authors":"N. Gharachorloo, S. Gupta, R. Sproull, I. Sutherland","doi":"10.1145/74333.74370","DOIUrl":"https://doi.org/10.1145/74333.74370","url":null,"abstract":"With widespread use of raster scan displays and the ever-increasing desire for faster interactivity, higher image complexity, and higher resolution in displayed images, several techniques have been proposed for rasterizing primitive graphical objects. This paper characterizes the performance of these techniques and shows how they evolve for more complex images on higher resolution displays. This characterization will not only show the strengths and deficiencies of existing rasterization techniques, but will also reveal new architectures for future raster graphics systems.","PeriodicalId":422743,"journal":{"name":"Proceedings of the 16th annual conference on Computer graphics and interactive techniques","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127079201","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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