Showing papers in "IEEE Computer Graphics and Applications in 1983"
TL;DR: By allowing the use of quadrants with cut corners, this modeling technique overcomes some of the drawbacks of standard quadtree encoding for finite element mesh generation.
Abstract: By allowing the use of quadrants with cut corners, this modeling technique overcomes some of the drawbacks of standard quadtree encoding for finite element mesh generation.
333 citations
TL;DR: Nonuniform, rational B-splines, capable of representing both precise quadric primitives and free-form curves and surfaces, offer an efficient mathematical form for geometric modeling systems.
Abstract: Nonuniform, rational B-splines, capable of representing both precise quadric primitives and free-form curves and surfaces, offer an efficient mathematical form for geometric modeling systems
328 citations
TL;DR: The proliferation of commercial systems over the past two years is noted, changes in system organization are discussed, work aimed at enhancing the geometric coverage, the applications coverage, and the performance of solid modeling systems is surveyed.
Abstract: The March 1982 issue of IEEE Computer Graphics and Applications was devoted to solid modeling. The lead article in that issuel summarized the history of the field and its status as of late 1981; this article is an update to the 1982 article. Here, we shall note the proliferation of commercial systems over the past two years, discuss changes in system organization, and summarize applications support. We shall also survey work aimed at enhancing the geometric coverage, the applications coverage, and the performance of solid modeling systems. Research is progressing swiftly on several fronts, and it is virtually certain that late-1980s solid modelers will be markedly more powerful than those available now.
318 citations
TL;DR: Classical ray-tracing techniques, which have produced the most realistic computer-generated images to date, are being enhanced in this developmental system.
Abstract: Classical ray-tracing techniques, which have produced the most realistic computer-generated images to date, are being enhanced in this developmental system.
234 citations
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TL;DR: Icons are not just religious images from Czarist Russia they are also pictures used by computer graphics designers to help improve the man-machine interface.
Abstract: Icons are not just religious images from Czarist Russia? they are also pictures used by computer graphics designers to help improve the man-machine interface.
176 citations
TL;DR: These new approaches to 3-D medical imaging promise better and more cost-effective object identification, representation, and manipulation in space and time.
Abstract: These new approaches to 3-D medical imaging promise better and more cost-effective object identification, representation, and manipulation in space and time.
119 citations
TL;DR: Digitally formatted 3-D imaging will become increasingly important in medical diagnosis, so what is the best trade-off of speed, picture quality, and storage requirements?
Abstract: Digitally formatted 3-D imaging will become increasingly important in medical diagnosis. What is the best trade-off of speed, picture quality, and storage requirements?
100 citations
TL;DR: A graphical extension of Pascal enables programmers to build complex 3-D objects and to describe their motions.
Abstract: A graphical extension of Pascal enables programmers to build complex 3-D objects and to describe their motions.
70 citations
TL;DR: Reduced data storage, simplified data, and faster plotting of designs on graphics displays' this algorithm has much to offer for IC mask making and CAD applications.
Abstract: Reduced data storage, simplified data, and faster plotting of designs on graphics displays?this algorithm has much to offer for IC mask making and CAD applications.
54 citations
TL;DR: The more complex the physical system, the greater the likelihood that hands-on operator training can damage it, and a computer model like Steamer offers a somewhat safer alternative.
Abstract: The more complex the physical system, the greater the likelihood that hands-on operator training can damage it. A computer model like Steamer offers a somewhat safer alternative.
46 citations
TL;DR: The GMSolid system can be implemented in most current geometric modeling systems as discussed by the authors, and it can be used in most of the current GMSOLVER systems, as well.
Abstract: Already operational in General Motors' GMSolid system, this technique can be implemented in most current geometric modeling systems.
TL;DR: In this detailed analysis of the two basic approaches to computer models for quadric surfaces, internal consistency emerges as the primary virtue of the superior model.
Abstract: In this detailed analysis of the two basic approaches to computer models for quadric surfaces, internal consistency emerges as the primary virtue of the superior model.
TL;DR: This technique for smooth surface interpolation over grid data reduces the number of extraneous local optima and inflection points of the surface.
Abstract: Compared with other methods, this technique for smooth surface interpolation over grid data reduces the number of extraneous local optima and inflection points of the surface.
TL;DR: The author covers Surface form selection (Interpolation versus approximation; Representation versus design; Smoothness; Shape fidelity; Local versus global methods; and Rendering), and Interpolation surfaces.
Abstract: The surface appropriate for a given problem depends on the application; there is no universal surface form. The numerous applications of surface methods include modeling physical phenomena (e.g., combustion) and designing objects such as airplanes and cars. In addition to these 3D surfaces, there are interesting 4D "surfaces" such as temperature as a function of the three spatial variables. Because the geometric information for these problems can be located arbitrarily in 3D or 4-Dimensional space, the schemes must be able to handle arbitrarily located data. The standard (and easier) approach to surfacesusing tensor products of curve methods-restricts the surface method's applicability to rectangularly "gridded" data. Two broad classes of methods suitable for solving these problems (i.e., problems for which simplifying geometric assumptions cannot be made) are (1) surface interpolants defined over triangles or tetrahedra and (2) distanceweighted interpolants. Users ordinarily want smoother surfaces than their data imply directly, so additional information must usually be created. (A notable feature of the methods shown here is that the smoothness of the surface is always greater than or equal to the smoothness of the defining data. The author covers Surface form selection (Interpolation versus approximation; Representation versus design; Smoothness; Shape fidelity; Local versus global methods; and Rendering), and Interpolation surfaces. It is noted that triangular interpolants and distance-weighted interpolants excel as surface methods because of their smooth interpolation of arbitrarily located data.
TL;DR: Solid modeling on an IBM PC?
Abstract: Solid modeling on an IBM PC? One exhibitor at NCGA '83?the National Computer Graphics Association's Fourth Annual Conference and Exposition held June 26-30 in Chicago?claimed such capability, while several other vendors demonstrated more conventional 2-D drafting capabilities on the PC. At each summer's round of graphics conferences, certain developments mark the latest direction of the industry. This year, the IBM PC-based systems indicate that graphics manufacturers are turning to a mostly untapped market?low-end CAD.
TL;DR: The data exchange specification is now well developed and tested, and more than 30 graphics system vendors have promised to supply IGES translators for their products.
Abstract: The data exchange specification is now well developed and tested, and more than 30 graphics system vendors have promised to supply IGES translators for their products.
TL;DR: A subpixel addressability feature allows this algorithm to address vector end points between pixel centers and helps it eliminate the Achilles' heel of raster displays¿jaggies.
Abstract: A subpixel addressability feature allows this algorithm to address vector end points between pixel centers and helps it eliminate the Achilles' heel of raster displays?jaggies.
TL;DR: This article is a retrospective look at a modeling effort involving the generation of a computer model from informal drawings and a plastic model of a helicopter, to gain some insights into the kinds of computeraided geometric design tools that would be appropriate to support this kind of work.
Abstract: This article is a retrospective look at a modeling effort involving the generation of a computer model from informal drawings and a plastic model of a helicopter When the exercise was taken on at the suggestion of a sponsor at the US Army Ballistic Research Laboratory (BRL) in Aberdeen, Maryland, we accepted the task as a means of examining a significant class of objects in which lofting was the predominant, characterizing modeling technique During the course of this modeling effort, we were able to gain some insights into the kinds of computeraided geometric design tools that would be appropriate to support this kind of work It is our expectation that from the results of a project like this we will see ways to develop a set of mathematical software tools in a "workbench environment" - tools that will make subsequent efforts to model related objects a much more straightforward process The Alpha_I System, which is an experimental spline-based solid modeler used to generate the models discussed in this article, is being developed in the Computer Science Department at the University of Utah Alpha_1 is intended to become part of an interactive environment that will eventually provide the designer with the kind of workbench necessary to carry out a large variety of tasks beyond specialized lofting projects
TL;DR: The algorithm presented here provides an adequately accurate mathematical representation of the intersection curve and provides a database to simplify such operations as hidden-surface removal, surface rendering, profile identification, and interference or clearance computations.
Abstract: When primitive parametric surfaces are combined and modified inferactively to form complex intersecting surfaces, it becomes important to find the curves of intersection. One must distinguish between finding the shape of the intersection curve, which might only be useful for display, and finding an accurate mathematical representation of the curve. The latter is important for any meaningful geometric modeling, analysis, design, or manufacture involving the intersection. The intersection curve between parametric surfaces is important in such computer-aided design and manufacturing (CAD/CAM) functions as shape design, analysis of groins, design of fillets, and computation of numerically controlled tooling paths. The algorithm presented here provides an adequately accurate mathematical representation of the intersection curve. It also provides a database to simplify such operations as hidden-surface removal, surface rendering, profile identification, and interference or clearance computations. Further, the algorithm facilitates creating and changing a finite element mesh in the intersection region.
TL;DR: The human brain responds to visual variables in predictable ways-something many graphics display creators should take into account when they organize and symbolize data.
Abstract: The human brain responds to visual variables in predictable ways-something many graphics display creators should take into account when they organize and symbolize data.
TL;DR: Many scientists and technicians rarely venture beyond 2-D plots in their computer graphics, but since an additional dimension is so helpful and accessible 3-D should be exploited.
Abstract: Many scientists and technicians rarely venture beyond 2-D plots in their computer graphics. Since an additional dimension is so helpful?and accessible?3-D should be exploited.
TL;DR: This integrated CAD/CAM system uses B-spline surfaces to model ship hulls and uses the resulting surface for the production of wooden towing tank models.
Abstract: This integrated CAD/CAM system uses B-spline surfaces to model ship hulls and uses the resulting surface for the production of wooden towing tank models.
TL;DR: The recent proliferation of algorithms that produce vector or raster drawings of space-filling models has advanced the understanding of the 3-D structure of molecules.
Abstract: The recent proliferation of algorithms that produce vector or raster drawings of space-filling models has advanced our understanding of the 3-D structure of molecules.
TL;DR: These shapes are easier to analyze and use in solid modeling systems than the more general quadric surfaces because they are naturally in mechanical design.
Abstract: Arising naturally in mechanical design, these shapes are easier to analyze and use in solid modeling systems than the more general quadric surfaces.
TL;DR: Converting from boundary to faceted representation results in a model that is well suited for fast hidden-surface removal, shaded pictures, and finite element mesh generation.
Abstract: Converting from boundary to faceted representation results in a model that is well suited for fast hidden-surface removal, shaded pictures, and finite element mesh generation.
TL;DR: A software processor developed at RPI adds color-shaded imaging capability to 3D geometric modeling systems, greatly enhancing their usefulness in industrial design applications as mentioned in this paper, which greatly enhances their usefulness.
Abstract: A software processor developed at RPI adds color-shaded imaging capability to 3-D geometric modeling systems, greatly enhancing their usefulness in industrial design applications.
TL;DR: In concentrating on developing the computer's internal electronic communicative abilities, we have neglected the interface between the machine's display surface and the human viewer as discussed by the authors, which is the most important interface between a human and a computer.
Abstract: In concentrating on developing the computer's internal electronic communicative abilities, we have neglected the interface between the machine's display surface and the human viewer.
TL;DR: By considering the linear operators associated with bivariate and multivariate interpolation/approximation schemes, it is shown how they can be compounded by operator multiplication and Boolean addition to obtain a distributive lattice of approximation operators.
Abstract: The mathematical techniques which form the foundation for most of the surface and volume modeling techniques used in practice are briefly described. An outline of what may be termed an operator calculus for the approximation and interpolation of functions of more than one independent variable is presented. By considering the linear operators associated with bivariate and multivariate interpolation/approximation schemes, it is shown how they can be compounded by operator multiplication and Boolean addition to obtain a distributive lattice of approximation operators. It is then demonstrated via specific examples how this operator calculus leads to practical techniques for sculptured surface and volume modeling.
TL;DR: If a computer and a draftsman are asked to draw a curve through identical planar data, the draftsman's curve frequently looks better.
Abstract: If a computer and a draftsman are asked to draw a curve through identical planar data, the draftsman's curve frequently looks better. Must it be this way?
TL;DR: The author explores the link between probability and geometry and concludes that urn models are a powerful tool for generating discrete probability distributions, and built into these special distributions are many propitious properties essential to the blending functions of computer-aided geometric design.
Abstract: The author explores the link between probability and geometry. In the process, he shows how to exploit simple probabilistic arguments to derive many of the classical geometric properties of the parametric curves and surfaces currently in vogue in computer-aided geometric design. He also uses this probabilistic approach to introduce many new types of curves and surfaces into computer-aided geometric design, and demonstrates how probability theory can be used to simplify, unify, and generalize many well-known results. He concludes that urn models are a powerful tool for generating discrete probability distributions, and built into these special distributions are many propitious properties essential to the blending functions of computer-aided geometric design. This fact allows mathematicians to use probabilistic arguments to simplify, unify, and generalize many geometric results. He believes that this link between probability and geometry will ultimately prove beneficial to both disciplines, and expects that it will continue to be a productive area for future inspiration and research.