Volume 05 (1986)
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Item EDITORIAL(Blackwell Publishing Ltd and the Eurographics Association, 1986)Item High Performance Colour Displays for Computer Graphics(Blackwell Publishing Ltd and the Eurographics Association, 1986) Denham, DenHigh-performance computer graphics displays for CAD utilize the Shadow-Mask CRT (SMCRT). Factors affecting colour-display quality and ergonomics include beam-to-beam convergence, beamspot profile, resolution, brightness, mask pitch, and image linearity. This paper briefly covers the results of recent experiments on eye fatique and vision. In particular, the effects of beam-to-beam misconvergence and poor spot performance in colour displays. Extensive discussion is given on beam-to-beam misconvergence: What it is, how it is corrected in different SMCRT types, and state-of-the-art techniques for controlling it. Emphasis is given to the digital-processor based convergence system employing feedback (autoconvergence). Also included are considerations given to selection of CRT types for high-performance graphics. CRTs are available with dot, slot, or line screens. There are also inline and delta configuration electron guns. Each combination of screen and gun offers tradeoffs in quality, performance, and cost.Item EUROGRAPHICS Individual Membership Application(Blackwell Publishing Ltd and the Eurographics Association, 1986)Item Generating Lines Using Quadgraph Patterns(Blackwell Publishing Ltd and the Eurographics Association, 1986) Parsons, Michael S.Item A Method of Displaying Transformed Picture Rectangles Using GKS Raster Functions(Blackwell Publishing Ltd and the Eurographics Association, 1986) Schumann, H.; Kotzauer, A.The GKS raster functions Fill Area and Cell Array allow area primitives in Computer Graphics to be used in a GKS environment.In implementing these functions, the computing time and memory required are important factors in deciding their usability especially for interactive work. The trend in the implementation of algorithms for such primitives is to use specialized hardware.In this paper, algorithms are introduced which are suitable for computers of low and middle efficiency and provide a sufficient image quality and an acceptable response time for dialogues.Item A Geometric Modeller Based on the Exact Octtree Representation of Polyhedra(Blackwell Publishing Ltd and the Eurographics Association, 1986) Navazo, I.; Avala, D.; Brunet, P.Geometric Modellers based on a Boundary Representation scheme are well suited for display operations, but boolean operations require algorithms with quadratic complexity. Using a class of extended octtrees which is presented here, boolean operations become linear, while exact recomputation of the boundary model in the case of polyhedral objects is possible, and memory requirements are less than in classical octtree encodings. Some bounds on the memory savings are given and discussed. The DMI system, a Geometric Modeller based on a hybrid model Boundary - Extended Octtrees, is presented, discussing the main operations and the interface between both models. Some modelling examples are shown. Finally, a generalization of the extended octtree encoding which allows the exact representation of objects limited by sculptured surfaces is presented.Item A Token Based Graphics System(Blackwell Publishing Ltd and the Eurographics Association, 1986) Reynolds, Graham J.This paper presents the design of a novel process oriented graphics systems architecture suitable for emulating many general purpose computer graphics systems. The systems architecture has been designed loosely on the actor model of computation, and consists of a number of functionally distinct modules or processes, which communicate solely by token (message) passing. The design addresses a specific requirement for configurability and adaptability of and between modules identified within interactive computer graphics systems.Item First Time Classroom Computer Graphics(Blackwell Publishing Ltd and the Eurographics Association, 1986) Kelly, Mary B.Item Image Generation by Space Sweep(Blackwell Publishing Ltd and the Eurographics Association, 1986) Muller, H.A method of using spatial coherence in image generation by raytracing is presented. The idea is to trace a set of rays in parallel. This is carried out by space sweep. Space sweep consists of moving a plane through the object space. The rays intersected by the plane are organized into a dynamic data structure R for range searching. When an object is met by the sweeping plane, those rays intersecting the object are found by a range search with the object in R. Exact complexity bounds are given for this algorithm, as well as details to allow practical application of this approach in image operation.Item Offers to EUROGRAPHICS Members(Blackwell Publishing Ltd and the Eurographics Association, 1986)Item General Assembly of the EUROGRAPHICS Association Thursday 28 August International Fair, Lisbon, Portugal.(Blackwell Publishing Ltd and the Eurographics Association, 1986)Item Teaching Workshop - December 1985(Blackwell Publishing Ltd and the Eurographics Association, 1986) Duce, D.A.Item Proposed Revisions to the EUROGRAPHICS UK Chapter Constitution(Blackwell Publishing Ltd and the Eurographics Association, 1986)Item EUROGRAPHICS -86(Blackwell Publishing Ltd and the Eurographics Association, 1986)Item EUROGRAPHICS Association, Geneva BALANCE SHEET AS AT JUNE 30th, 1986(Blackwell Publishing Ltd and the Eurographics Association, 1986)Item Multiprocessor Ray Tracing(Blackwell Publishing Ltd and the Eurographics Association, 1986) Cleary, John G.; Wyvill, Brian M.; Birtwistle, Graham M. and Vatti, ReddyA 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.Item A Survey of Contouring Methods(Blackwell Publishing Ltd and the Eurographics Association, 1986) Sabin, MalcolmItem CALL FOR PAPERS(Blackwell Publishing Ltd and the Eurographics Association, 1986)Item EUROCRAPHICS UK 1986: Clasgow Conference(Blackwell Publishing Ltd and the Eurographics Association, 1986) Matthew, A.J.The Conference was held on the three days 24th to 26th March at Glasgow University, the first day devoted to two parallel tutorials, the second day opening the conference proper and including meetings of special interest groups and the final day consisting of submitted and invited papers.Item EUROGRAPHICS Institutional Membership Form(Blackwell Publishing Ltd and the Eurographics Association, 1986)