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Now showing 1 - 10 of 65
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    Towards a Z-Buffer and Ray-Tracing Multimode System based on Parallel Architecture and VLSI chips
    (The Eurographics Association, 1986) P.Lemy,; W. Strasser
    After the hidden surfaces algorithms for 3D rastergraphics, hardware design isthe main problem, for many applicat ions, such as : Audiovisual animat ions. CADCAM,and simulation.After a short description of our CUBI 7 system (a 3D real-time Z-buffer system),and its CRISTAL module which increases RAY-TRACING computations, we present ourhardware project based on :-Parallel architecture for RAY-TRACING, special effects ; This module is alsouseful for pre-processing the image : (rotations, clipping, perspective transform... ).-A or Z-BUFFER which will be designed on VLSI chips polygon filling will be alsodesigned with pipe-lined chips."
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    Biom orphs: Computer Displays of Biological Forms Generated from Mathematical Feedback Loops
    (Blackwell Publishing Ltd and the Eurographics Association, 1986) Pickover, C.A.
    A computer graphics algorithm is used to create complicated forms resembling invertebrate organisms. These natural morphologies are generated through the iteration of mathematical transformations. Several illustrations are chosen as examples of the diversity of biological structures which result from this technique.
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    Multi-Dimensional Graphics: Algorithms & Applications
    (The Eurographics Association, 1986) Inselberg, Alfred; A.A.G. Requicha
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    An Introduction to the Graphics Systems Processor
    (The Eurographics Association, 1986) Short, Graham; A.A.G. Requicha
    This paper describes the system applications of the Graphics System Processor (GSP) produced by Texas Instruments Inc. The paper discusses the general-purpose capabilities of the GSP which make it a flexible processor to use. It then goes on to show how the graphics-specific parts of the GSP make it a powerful tool, ideally suited to graphics applications. Finally the paper discusses some of the programmable hardware functions of the GSP which make it easy to design into any graphics system.
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    Overlap Operations and Raster Graphics
    (Blackwell Publishing Ltd and the Eurographics Association, 1986) Thomas, A.L.
    This paper outlines the development of a volume and surfaces modelling system for use with raster graphic displays. The ideas are presented in a historical framework to make the reasoning behind the design decisions clear and to indicate the main influences which have guided the work. There are two outcomes of importance: a language form for defining volumes and surfaces and hardware to convert this representation directly into a display. The hardware provides hidden-line or hidden-area removal as a display primitive which, in an appropriate implementation, can be fast enough to support a range of real-time display applications. Linked to this hidden-line, hidden-area removal facility is an ability to provide interference tests for objects that are being moved around in a scene. Again there appears to be a hierarchy of applications ranging in complexity from interactive volume editing to robot control and vision systems. The new facilities complement existing point and line based display operations, on which most current displays- hardware is based. A good case is emerging for integrating the two approaches into a single hardware implementation for CAD workstations and for simulator display systems.
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    Two Algorithms for Decomposing a Polyhedron into Convex Parts
    (Blackwell Publishing Ltd and the Eurographics Association, 1986) Szilvasi-Nagy, M.
    Two algorithms are presented for splitting a polyhedron into convex components: one for the case of a simple polyhedron and one for a more general case, when the polyhedron may have ring-shaped faces and cavities. The time requirement in both cases is O(DNlogN), where D is the number of concave dihedral angles and N is the number of edges. The algorithm for the simple oasis produces at most D+ 1 convex pieces which is the minimal number of the convex components.
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    The Priority Tree, a HL/HSR Approach for PHIGS
    (Blackwell Publishing Ltd and the Eurographics Association, 1986) Abi-Ezzi, S.S.
    The Programmer-s Hierarchical Interactive Grahics System (PHIGS) specifies an interface for programming device-independent computer graphics applications. PHIGS provides a powerful data grouping mechanism, called the PHIGS structure, that may be used to model the geometry of 3D objects. Hidden Line/Hidden Surface Removal (HL/HSR) is a required process to produce realistic solid views of the modeled objects. Modeling clip is an essential process for viewing a clipped portion of the modeled objects. A technique is presented that provides HL/HSR and modeling clip as added utilities to PHIGS. The technique is based on the Binary Space Partitioning (BSP) tree (sometimes called priority tree), and involves a back to front sorting of the primitives of a PHIGS structure network to another PHIGS structure. Modeling clip is achieved by limiting the sorting to those primitives in a specified clip ping region of the object space. The resulting structure when displayed on a raster device produces a realistic view of the possibly clipped object that was originally modeled by the PHIGS structure network.
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    Fast Operations on Raster Images with SIMD Machine Architectures
    (Blackwell Publishing Ltd and the Eurographics Association, 1986) Arabnia, H. R.; Oliver, M. A.
    Algorithms for fast operations on a raster image data structure are described. The data structure and algorithms have been designed to exploit SIMD parallel architectures. Images of lines, discs and circles can be created efficiently. Images can be translated, scaled, and combined. The data structure is closely related to runlength encodement. The algorithms have been implemented on an ICL DAP on which the operations can be done in real time (on non-trivial images).
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    Multiprocessor Ray Tracing
    (Blackwell Publishing Ltd and the Eurographics Association, 1986) Cleary, John G.; Wyvill, Brian M.; Birtwistle, Graham M. and Vatti, Reddy
    A multiprocessor algorithm for ray tracing is described. The performance of the algorithm is analysed for a cubic and square array of processors with only local communication between near neighbours. Theoretical expressions for the speedup of the system as a function of the number of processors are derived. These analytic results are supported by simulations of ray tracing on a number of simple scenes with polygonal surfaces. It is found that a square network of processors generally performs better than a cubic network. Some comments are made on the construction of such a system using current (1985) microprocessor technology.
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    An Implementation of the GKS-3D/Phigs Viewing Pipeline
    (The Eurographics Association, 1986) Singleton, Karen; A.A.G. Requicha
    Following the establishment of GKS as the first international standard for computer graphics, two new standards, GKS-3D and PHIGS, are emerging which cater for three dimensional graphics. In order to display a 3-D object, a description of how it is to be viewed must be given. GKS-3D and PHIGS provide a viewing pipeline to generate the parallel or perspective view required. This paper describes in detail the functionality and an implementation of the GKS-3D/PHIGS viewing pipeline.