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Computer Graphics and Applications, IEEE

Issue 4 • Date July 1990

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Displaying Results 1 - 8 of 8
  • Surfaces-techniques for cubic algebraic surfaces

    Publication Year: 1990 , Page(s): 14 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1057 KB)  

    The tutorial presents some tools for free-form modeling with algebraic surfaces, that is, surfaces that can be defined using an implicit polynomial equation f(x, y, z)=0. Cubic algebraic surfaces (defined by an implicit equation of degree 3) are emphasized. While much of this material applies only to cubic surfaces, some applies to algebraic surfaces of any degree. This area of the tutorial introduces terminology, presents different methods for defining and modeling with cubic surfaces, and examines the power basis representation of algebraic surfaces. Methods of forcing an algebraic surface to interpolate a set of points or a space curve are also discussed. The parametric definition of cubic surfaces by imposing base points is treated, along with the classical result that a cubic surface can be defined as the intersection locus of three two-parameter families of planes. Computer-generated images of algebraic surfaces created using a polygonization algorithm and Movie. BYU software illustrate the concepts presented.<> View full abstract»

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  • Radiosity redistribution for dynamic environments

    Publication Year: 1990 , Page(s): 26 - 34
    Cited by:  Papers (6)  |  Patents (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (947 KB)  

    The radiosity algorithm is extended to dynamic environments, providing global-illumination simulations to scenes that are modified interactively. The illumination effects introduced by a change in position, shape, or attributes of any object in the scene are computed very rapidly by redistributing the energy already exchanged between objects. Corrections are made by shooting positive and negative energy, accounting for increased illumination and the creation of shadows. Object coherence is used to minimize computation, and progressive-refinement techniques are used to accelerate convergence. The extended algorithm yields excellent approximations to the exact solutions at interactive speeds.<> View full abstract»

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  • Visibility determination on projected grid surfaces

    Publication Year: 1990 , Page(s): 36 - 43
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB)  

    An algorithm is presented for solving the hidden-line and hidden-surface problems on grid surfaces, such as graphs of bivariate functions specified by their values on a set of grid points. The algorithm is implemented in image space, taking advantage of the raster display resolution. The procedure examines the edges of a projected grid surface in a systematic order to find all points visible to the observer from which a visible periphery for the surface is established. As the algorithm proceeds, this changing periphery floats toward the edges of the visible parts of the solid surface and determines the visibility of every point of the edges being processed. The procedure is therefore termed the floating perimeter algorithm. (FPA).<> View full abstract»

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  • RenderMan: pursuing the future of graphics

    Publication Year: 1990 , Page(s): 44 - 49
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (665 KB)  

    RenderMan, a powerful, consistent, yet simple 3-D interface that can adequately describe the most common rendering techniques and provides expandability for future growth is described. The RenderMan interface partitions the process of generating realistic images into two distinct areas, modeling and rendering. RenderMan's features are briefly outlined, and the RenderMan Shading language and interface bytestream protocol are examined. Hardware independence and the acceptance of RenderMan are discussed.<> View full abstract»

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  • A visualization programming environment for multicomputers

    Publication Year: 1990 , Page(s): 50 - 58
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (747 KB)  

    The programming and run-time environment used for the authors' multicomputer visualization software are described. The particular approach to using multicomputers for scientific visualization provides a uniform interface to system and communications facilities and promotes modularity and code reuse. No breakthrough technology is involved; rather, a collection of methods that have been developed by others has been optimized for visual computing applications and unified into a system that is simple to use and easy to port to new hardware. The C language is used. Initial experience with the system has been good.<> View full abstract»

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  • A dataflow toolkit for visualization

    Publication Year: 1990 , Page(s): 60 - 69
    Cited by:  Papers (34)  |  Patents (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1145 KB)  

    A toolkit known as apE is presented. Originally, this was an acronym for animation production environment, but apE has become known as a software designed for more than just animation. Previous work is briefly reviewed, and the processing of designing the system is discussed. Common elements in building any graphics system as well as elements particular to building a large system are examined. The design and construction of apE 1.1 and apE 2.0 are described. The policy governing the distribution of apE and the advantages of academic software development are discussed.<> View full abstract»

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  • Portability of interactive graphics software

    Publication Year: 1990 , Page(s): 70 - 75
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    One solution to obtaining a portable graphics architecture is presented. By abstracting the functionality present in most 3-D graphics systems and augmenting it with advanced rendering features, a highly portable, efficient, and modern graphics architecture for interactive 3-D graphics applications (including modeling, animation, and scientific visualization) is obtained. Using appropriate object-oriented design procedures ensures the efficiency, maintainability, and portability of the architecture. The design and implementation of the graphics system used to achieve this high degree of portability are described.<> View full abstract»

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  • NetCDF: an interface for scientific data access

    Publication Year: 1990 , Page(s): 76 - 82
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (665 KB)  

    The network common data form (NetCDF), a data abstraction for storing and retrieving multidimensional data, is described. NetCDF is distributed as a software library that provides a concrete implementation of that abstraction. The implementation provides a machine-independent format for representing scientific data. Together, the abstraction, library, and data format support the creation, access, and sharing of scientific information. NetCDF is useful for supporting objects that contain dissimilar kinds of data in a heterogeneous network environment and for writing application software that does not depend on application-specific formats. Independence from particular machine representations is achieved by using a nonproprietary standard for external data representation. The discussion covers NetCDF data abstraction and interface; dimensions, variables, and attributes; direct access and hyperslab access, the NetCDF library; the data format; ncdump and ncgen utilities; experience, usability, and performance; limitations of NetCDF; and future plans.<> View full abstract»

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IEEE Computer Graphics and Applications bridges the theory and practice of computer graphics.

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L. Miguel Encarnação
University of Iowa