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Item Fast Previewing Techniques in Raster Graphics(The Eurographics Association, 1983) Jansen, F.W.; Wijk, J.J. van; P.J.W. ten HagenThe long processing times inherent in the use of raster graphics techniques for the shading of complex scenes, complicate the design and debugging of a picture. The efficiency of the picture-generating process can, however, be improved by adding several interactive facilities to the system. In particular, fast previewing techniques are valuable for checking the modeling and for getting a good impression in an early stage of the picture-definition process. A discussion of raster graphics system design is followed by examples of fast pre-viewing techniques for the shading and texture mapping of surface models and for the shading of solid models using a raycasting technique.Item A Delaunay-Based Method for Surface Approximation(The Eurographics Association, 1983) Floriani, L.De; Falcidieno, B.; C.Pienovi,; P.J.W. ten HagenThis paper describes a method for constructing a surface representation model from a given set of data points.A Triangulated Irregular. Network has been chosen as data structure, thus representing the surface as a set of contiguous non -overlapping and irregurarly shaped triangular facets.The proposed method makes use of a Delaunay triangular grid adapted to non-convex domains. Using only representative subsets of the given set of points, the method allows the construction of approximating surfaces which rest within a predefined tolerance.Item GKS-300 - PASCAL Implementation of the Graphical Kernel System (GKS) on a Minicomputer Based Graphical Workstation(The Eurographics Association, 1983) Schmitgen, Günther; P.J.W. ten HagenItem Non-Rectangular Surface Patches Suitable for Inclusion in a B-Spline Surface(The Eurographics Association, 1983) Sabin, M.A.; P.J.W. ten HagenItem Closed 2D Contour Algorithms for 3D Reconstruction(The Eurographics Association, 1983) Huijsmans, D. P.; P.J.W. ten HagenIn collaboration with the department of Anatomy a software package (FORTRAN 77) for 3D reconstruction of anatomical material is under development. Input material consists of a series of planparallel slices of an embedded specimen. 3D reconstruction of volume segments with closed 3D surface boundaries is achieved by taking closed 2D contour boundaries within each intersecting plane.Item Syntactic Methods in Computer Graphics(The Eurographics Association, 1983) Slavik, P.; P.J.W. ten HagenItem Refinement of the Stress Contour Plots by the Local Interpolations, Extrapolations ans Averaging(The Eurographics Association, 1983) Draskovic, Z.; Berkovic, M.; P.J.W. ten HagenThe purpose of this paper is an attempt to improve the stress contour plots for the simplest two-dimensional finite elements. The proposed approach is achieved by the use of the simple local interpolations, extrapolations and averaging of the existing stress analysis results. The usual and the proposed, refined procedure are compared for two typical examples.Item Interactive Graphical Planning(The Eurographics Association, 1983) Jackson, Michael J.; Clark, Tony; P.J.W. ten HagenAccurate planning is an essential part of efficient project management, but computer-aided techniques have, in the past, not fulfilled their potential in this important field, This paper describes how interactive graphics techniques have been used to help the planner in the design of his programme of work and in the dissemination of his recommended plan.Item The GHOST-80 Colour Raster Extensions(The Eurographics Association, 1983) Prior, W.A.J.; Sutherland, R.J.; P.J.W. ten HagenThe GHOST Graphical Output System has been developed over a long period. The most recent version, GHOST-80 has been enhanced with routines for colour raster displays. The integration of these routines with the existing package is described and their ease of use is emphasised.Item On Developing a GKS Driver Architecture for Raster Workstations(The Eurographics Association, 1983) Rix, Joachim; P.J.W. ten HagenThe use of raster graphics devices needs adapting to graphics applications. The first graphics standard, the Graphics Kernel System GKS, defines a logical interface on an application and device independent level. The workstation driver maps the logical GKS functions to device functions. First some special raster device facilities are outlined and then it is shown how to use them within the driver. To reduce the amount of driver implementations a common driver concept is sought here, especially for raster devices.