EG1985 Proceedings (Technical Papers)
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HUTWINDOWS: AN APPROACH TO USER INTERFACE DEVELOPMENT
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Koivunen, Marja-Riitta
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Mntyl, Martti
THE USE OF GRAPHICAL SYMBOLIC COMMANDS (ICONS) IN APPLICATION PROGRAMS
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Woodgate, H. Sam
An illumination model for ray-tracing
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MONTCEL, Bruno TEZENAS DU
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NICOLAS, Alain
GRAPHICS PROGRAMMING FOR KNOWLEDGE-GUIDED INTERACTION
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Tibbert, Lee
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Bergeron, R. Daniel
PIPEMATIC: A DISTRIBUTED SYSTEM FOR THE DESIGN OF GEOMETRICALLY TIGHT PIPING STRUCTURES
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Sulonen, Reijo
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Tikkanen, Matti
A CONCEPT FOR A GKS MACHINE
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Herman, Iván
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Reviczky, János
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Tolnay-Knefély, Tibor
SUBACTOR DATA TYPES AS HIERARCHICAL PROCEDURAL MODELS FOR COMPUTER ANIMATION
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Magnenat-Thalmann, N.
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D.Thalmann,
CREATING CSG MODELLED PICTURES FOR RAY-CASTING DISPLAY
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CORDONNIER, E.
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BOUVILLE, C.
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DUBOIS, J.L.
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MARCHAL, I.
A Three-Dimensional Shaded Display Method for Voxel-Based Representation
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OHASHI, Toshiaki
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UCHIKI, Tetsuya
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TOKORO, Mario
DETERMINATION OF LOCAL COORDINATE SYSTEMS FOR TEXTURE SYNTHESIS ON 3-D SURFACES
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MA, SONG DE
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GAGALOWICZ, ANDRE
MODEL DRIVEN SYNTHESIS OF NATURAL TEXTURES FOR 3-D SCENES
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GAGALOWICZ, ANDRE
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MA, SONG DE
GEOMETRIC MODELLING USING EXACT OCTREE REPRESENTATION OF POLYHEDRAL OBJECTS
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Brunet, Pere
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Navazo, Isabel
TOUCHSCREEN AND COMPUTER GRAPHICS IN A SCIENCE MUSEUM
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Clerget, Yves
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Cottrell, Vincent
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Raoust, Michel
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Withnell, Jean
INTEGRATED GRAPHICS ENIVRONMENT EASES AVIONIC DISPLAY SOFTWARE DEVELOPMENT
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BRATEL, Alain
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CLAPIER, Christian
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ETTER, Michel
NEM: A LANGUAGE FOR ANIMATION OF ACTORS AND OBJECTS
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Marino, Giuseppe
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Morasso, Pietro
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Zaccaria, Renato
VIEWING SOLID MODELS BY BINTREE CONVERSION
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Koistinen, Petri
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Tamminen, Markku
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Samet, Hanan
EXTENDING GKS TO A DISTRIBUTED ARCHITECTURE
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R.Bettarini,
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G.Faconti,
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L.Moltedo,
BICEPS - THE INTERACTIVE GRAPHICS AIDED SYSTEM FOR BI-DIMENSIONAL GEOMETRY YODELING, NESTING AND FLAME CUTTING TECHNOLOGY
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Kobvlinski, Wiktor J.
FRACTIONAL BROWNIAN RELIEF : AN EXACT LOCAL METHOD
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FELLOUS, A.
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GRANARA, J.
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HOURCADE, J. C.
Graphics Programming with "Archetypes" - A Preliminary Study -
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Martins, Fernando Mar io
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Oliveira, Jose Nuno
AN INTERACTIVE RENDERING TECHNIQUE FOR 3-D SHAPES
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KONDO, Kunio
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KIMURA, Fumihiko
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TAJIMA, Taro
A GENERALISATION OF THE TIMMER BLENDING FUNCTIONS FOR BEZIER-TYPE CUBIC CURVES
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NTOKO, NZUMBE-MESAPE
Configuring Reference Systems for Certifying GKS Implementations
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Gbel, M.
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Hbner, W.
PIPELINE APPROACH FOR BUILDING THE PRESENTATION GRAPHICS SYSTEMS
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Klimenko, S.V.
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Kochin, V.N.
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Samarin, A.V.
TABLE LOOK-UP GRAPHlC INTERPOLAT ION
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Alia, G.
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Barsi, F.
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Martinelli, E.
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Tani, N.
GENERALIZATION OF CONTOUR TRACKING IN IMAGE SYNTHESIS, AND APPLICATION
[meta data] [files:
Hegron, Gerard
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Item HUTWINDOWS: AN APPROACH TO USER INTERFACE DEVELOPMENT(The Eurographics Association, 1985) Koivunen, Marja-Riitta; Mntyl, Martti; C.E. VandoniThe design and implementation of good graphical user interfaces is a difficult task requiring good taste and proper tools. The HutWindows system under development at Helsinki University of Technology is intended to be an easy-to-use set of tools for implementing a graphical user interface to an application having a simple text-oriented interface. It provides a single input channel for interleaved input from a collection of non-overlapping windows, and output primitives for the display of text and graphics. All details of the user interface are effectively hidden from the application, and can be modified by the user without touching the application code.Item THE USE OF GRAPHICAL SYMBOLIC COMMANDS (ICONS) IN APPLICATION PROGRAMS(The Eurographics Association, 1985) Woodgate, H. Sam; C.E. VandoniThis paper describes the use of Graphical Symbols (Icons) as a means of communicating operating commands between application program and users. detailed in the paper is the operational command system for a "Spread Sheet Calculator" which was &signed to be driven entirely by Graphical Symbols using a "point and activate" command method. 83 Graphical Symbols were required to operate the program and these were developed using a "graphical symbol generator". The example User experiences are also discussed.Item An illumination model for ray-tracing(The Eurographics Association, 1985) MONTCEL, Bruno TEZENAS DU; NICOLAS, Alain; C.E. VandoniItem Item GRAPHICS PROGRAMMING FOR KNOWLEDGE-GUIDED INTERACTION(The Eurographics Association, 1985) Tibbert, Lee; Bergeron, R. Daniel; C.E. VandoniThis paper describes a design approach that combines knowledge engineering techniques with an interactive graphics program. A prototype for specifying computer systems interactively is used to demonstrate the design approach. The program incorporates a rule-based knowledge engineering module which allows for both data base consistency and the ability to guide the user through an interactive dialogue.Item A CSG LIST PRIORITY HIDDEN SURFACE ALGORITHM(The Eurographics Association, 1985) Jansen, F.W.; C.E. VandoniSeveral algorithms exist for visualizing geometric models defined by constructive solid geometry (CSG). Each of these algorithms is based on standard hidden surface methods, such as ray tracing, scan-line and z-buffer algorithms. In this paper a CSG list priority algorithm is described that is combined with a ray tracing algorithm in the use of a spatial subdivision technique and a CSG list structure to exploit CSG coherence. The combined algorithm is designed for interactive viewing and high quality rendering of CSG models with faceted primitives.Item PIPEMATIC: A DISTRIBUTED SYSTEM FOR THE DESIGN OF GEOMETRICALLY TIGHT PIPING STRUCTURES(The Eurographics Association, 1985) Sulonen, Reijo; Tikkanen, Matti; C.E. VandoniThe main principles of an interactive design system intended for the solution of 3D geometric placement problems are described. The first applications for the system will be related to the design of machine rooms in ships where a large number of geometric objects must be placed and connected together with appropriate piping structures. However, the system is application independent. The emphasis of this paper is on the systems structure, algorithmic problems are not dealt with. Implementation of the system is currently underway.Item A CONCEPT FOR A GKS MACHINE(The Eurographics Association, 1985) Herman, Iván; Reviczky, János; Tolnay-Knefély, Tibor; C.E. VandoniGeneral ideas for the creation of a very intelligent graphic terminal are presented; this terminal should know all GKS functionalities, including the future 3D Standard as well. Multiple Workstation concept is maintained and it i s realized by linking it to a multiple context-frame handling.Item SUBACTOR DATA TYPES AS HIERARCHICAL PROCEDURAL MODELS FOR COMPUTER ANIMATION(The Eurographics Association, 1985) Magnenat-Thalmann, N.; D.Thalmann,; C.E. VandoniAn innovative kind of procedural model for computer animation is presented in the form of subactor data types. When a subactor data type is defined, many instances of this type may be defined. Each occurrence has the same parameters, but the animation laws applied to the parameters may be completely different. These occurrences of subactors as well as the associated animation laws are controlled in a user-friendly way. Several subactors may be dependent on an actor which may also be globally animated. Subactors based on Coons surfaces and beta-splines surfaces are discussed. Several examples are presented including a clock, a robot and a mask.Item CREATING CSG MODELLED PICTURES FOR RAY-CASTING DISPLAY(The Eurographics Association, 1985) CORDONNIER, E.; BOUVILLE, C.; DUBOIS, J.L.; MARCHAL, I.; C.E. Vandoni30-picture synthesis systems used for instance in the audiovisual field or networked services require the implementation of easy-to-use aids to composition. This particular composition software realizes the sizing and locating of even complex CSG objects in a simple and direct manner. The Ray-casting method is used for display and designation.Item A Three-Dimensional Shaded Display Method for Voxel-Based Representation(The Eurographics Association, 1985) OHASHI, Toshiaki; UCHIKI, Tetsuya; TOKORO, Mario; C.E. VandoniIn this paper, methods for displaying solid objects represented by a three-dimensional array of voxels are described. The Linear Interpolating Projection Method is proposed as a method by which such objects can be projected onto the screen in perspective. In order to shade the projected images, the Depth only Shading Method is proposed. These methods are so simple that three-dimensional perspective images with shading can be produced rapidly. This paper also describes an architecture based on these methods for generating animation interactively.Item DETERMINATION OF LOCAL COORDINATE SYSTEMS FOR TEXTURE SYNTHESIS ON 3-D SURFACES(The Eurographics Association, 1985) MA, SONG DE; GAGALOWICZ, ANDRE; C.E. VandoniWe propose and compare three types of local coordinate systems and describe their geometric properties Several results of texture synthesis on 3-D surfaces using these local coordinate systems are presented The synthesis procedure is driven by a texture model including only a small amount of statistical parametersItem GKS Inquiry Functions within Prolog(The Eurographics Association, 1985) Sykes, Pete; Krishnamurti, Ramesh; C.E. VandoniThis paper discusses the semantics of the GKS inquiry functions within a Prolog environment and illustrates the flexibility built into a proposed Prolog binding.Item A 3-D CELLULAR FRAME BUFFER(The Eurographics Association, 1985) Kaufman, Arie; Bakalash, Reuven; C.E. VandoniA new architecture for storing and processing of threedimensional (3-D) graphics is described, The 3-D objects are discretized and stored in a full 3-D cellular memory of voxels. A 3-D graphics processor scan-converts 3-D geometric objects into the cellular representation. A 3-D frame buffer processor manipulates 3-D cellular sub-boxes and controls 3-D interaction. Displaying 2-D orthographic projections from a given view position and direction is accomplished by a 3-D viewing processor. With this new architecture, there is neither a need for repeatedly scan-converting modified geometric objects nor a need for removing hidden-surfaces.Item MODEL DRIVEN SYNTHESIS OF NATURAL TEXTURES FOR 3-D SCENES(The Eurographics Association, 1985) GAGALOWICZ, ANDRE; MA, SONG DE; C.E. VandoniThis paper presents a new method for the synthesis of textures on 3-D surfaces. With the exception of fractals, graftals and particle systems used for very restricted types of textures, one basic technique for the faithful reproduction of textures has been presented in the literature up to now. In this standard method, textures are synthesized by mapping a rectangular template onto a patch of the curved surface. In the method proposed here, the synthesis is achieved continuously on the surface by interpolating only statistics of the texture which have a much narrower spectrum than the texture itself so that there are no aliasing effects. A vast class of textures can be reproduced with a visual appearance similar to the reference texture used. The method applies for any 3-D surface and is relatively quick and easy.Item GEOMETRIC MODELLING USING EXACT OCTREE REPRESENTATION OF POLYHEDRAL OBJECTS(The Eurographics Association, 1985) Brunet, Pere; Navazo, Isabel; C.E. VandoniIn the last few years, octrees have been proposed for the representation of solids in Geometric Modelling systems. Using them, boolean operations are simple; however, they use a great amount of memory and it is very difficult to obtain smooth graphical outputs from them or to recompute the boundary model. In the present paper, a new class of Octtrees is introduced, which allows face, edge and vertex nodes as well as the classical white, black and grey nodes. The required amount of storage is less than in the case of classical Octtrees, and boolean operations are also simple. Futhermore, there exists an algorithm for the exact recomputation of the boundary model.Item TOUCHSCREEN AND COMPUTER GRAPHICS IN A SCIENCE MUSEUM(The Eurographics Association, 1985) Clerget, Yves; Cottrell, Vincent; Raoust, Michel; Withnell, Jean; C.E. VandoniScientific information presented by a Science Museum must be both easily understood and easily memorized. Public interest must be maintained at a very high level during the presentation: interaction of the public with the message is greatly desirable. Computer techniques which mix user-friendly software, colour graphics and a touch-screen as the input device satisfy these requirements. This paper describes a scientific "game" designed to teach the player the sensitivity of architecture and climate in indoor comfort and energy consumption. It is based on a micro-computer, the IBM-PC, and a touch-screen and it uses colour graphics to convey information. The software benefits from a three-year experience at La Villette in the design of scientific exhibits for a large public. In this article the cost of software and hardware are mentioned.Item INTEGRATED GRAPHICS ENIVRONMENT EASES AVIONIC DISPLAY SOFTWARE DEVELOPMENT(The Eurographics Association, 1985) BRATEL, Alain; CLAPIER, Christian; ETTER, Michel; C.E. VandoniAn original methodology to develop real-time graphics software is presented. It will supply efficient software production for avionic display systems. The purpose is a complete specification, simulation and programming environment. The first available tool is ODISSEE, a computer aided design software for avionic symbologies including a graphics editor and a database manager. Although it is part of the avionic display integrated environment, ODISSEE is a portable graphics device independent and highly interactive general purpose software.Item AN IMPROVEMENT OF THE RAY-TRACING ALGORITHM(The Eurographics Association, 1985) COQUILLART, Sabine; C.E. VandoniThis paper describes an improvement of the ray-tracing algorithm. The new method takes advantage of a data structure which allows us to consider only the closest objects to the path of the ray. This technique can be applied to primary and secondary rays. Using this method, the run-time depends more on the complexity of the generated picture than on the complexity of the scene.Item NEM: A LANGUAGE FOR ANIMATION OF ACTORS AND OBJECTS(The Eurographics Association, 1985) Marino, Giuseppe; Morasso, Pietro; Zaccaria, Renato; C.E. VandoniThe animation of actors and objects is considered in the framework of knowledge representation, with particular regard to motor knowledge. In our opinion, a formal model for motor knowledge should fill a gap between action planning and low level computer animation graphics; such model should be able to "virtualize" the actor and the interaction with the environment so that the planner could produce (and rely on) high level abstract actions, characterized by high autonomy and naturality. The paper discusses some general aspects about actions, actors, and scenes, and finally describes the NEM language, for the representation and animation of humanoids in a scene, which is meant to provide a software laboratory for experimenting with action schemas.Item VIEWING SOLID MODELS BY BINTREE CONVERSION(The Eurographics Association, 1985) Koistinen, Petri; Tamminen, Markku; Samet, Hanan; C.E. VandoniA hidden surface algorithm is presented for viewing constructive solid geometry representations of solids (CSG trees) by converting them implicitly into a 3-d recursive spatial subdivision (bintree). The algorithm prunes the CSG tree to its minimal representation within each bintree block and does not evaluate it in regions of space (bintree nodes) that are totally hidden to the observer.Item EXTENDING GKS TO A DISTRIBUTED ARCHITECTURE(The Eurographics Association, 1985) R.Bettarini,; G.Faconti,; L.Moltedo,; C.E. VandoniThe recently adopted standards in the fields of computer networks and computer graphics has given to the opportunity to start a project to develop a distributed model of the Graphical Kernel System (GKS). The aim of this project is to offer a uniform accessible set of graphical services to the community of scientific and technical users belonging to the National Reserch Council, Universities and other research institutions in Italy. This paper outlines some major problems encountered in the definition of the model of the distributed GKS, and proposes solutions.Item RASTER ROTATION OF BILEVEL BITMAP IMAGES(The Eurographics Association, 1985) Hersch, Roger D.; C.E. VandoniA fast raster rotation algorithm based on nearest-neighbour interpolation is described. Essentially, the computation consists of two additions/subtractions and two rounding operations per rotated image pixel. The rotation time, is about equal to the time needed for the pixelwise duplification of an image of the same size. "Nearest-neighbour" interpolation and "ideal" interpolation are compared. Because of non-linearities introduced by binary threshold operations, both interpolation functions are found to be equivalent. From spectral analysis of nearest-neighbour interpolation and from spatial analysis of rotated pixels, it is shown that image frequencies should not be higher than one quarter of the sampling rate. In order to rotate large images, an image memory management module is used for swapping transparently image blocks between main memory and disk.Item BICEPS - THE INTERACTIVE GRAPHICS AIDED SYSTEM FOR BI-DIMENSIONAL GEOMETRY YODELING, NESTING AND FLAME CUTTING TECHNOLOGY(The Eurographics Association, 1985) Kobvlinski, Wiktor J.; C.E. VandoniAn essential condition for effective usage of numerically controlled devices is their correct and efficient programming. Especially in cutting applications every nesting layout requires a new control program tape. The BICEPS system referred here has been implemented in work shops with both: batch production - very stable one and simple part cutting in repair shops where every day new parts are manufactured. In both cases significant material savings (by narrow nesting) and reduction of production preparation time are obtained. The present paper deals with the very first step of production preparation process: modeling of the geometry of Bi-dimensional (2D) contours of Darts manufactured.Item FRACTIONAL BROWNIAN RELIEF : AN EXACT LOCAL METHOD(The Eurographics Association, 1985) FELLOUS, A.; GRANARA, J.; HOURCADE, J. C.; Vandoni, C. E.Fractional Brownian process has been widely used for computer rendering of terrain models. The implementation constraints in Computer Graphics have led to the use of recursive methods, based on some local properties of this model. We present in this article s mathematical study of these local properties and propose a local model for fractal modeling based on strict observance of fractional Brownian probability law.Item Graphics Programming with "Archetypes" - A Preliminary Study -(The Eurographics Association, 1985) Martins, Fernando Mar io; Oliveira, Jose Nuno; C.E. VandoniThis paper is a brief report on the initial phase of the formal development of a graphics programming system. At this stage of the specification, the system architecture is just outlined and attention is focussed on the conceptual level. The abstract notion of a graphic 'archetype' is introduced and proposed as a basis for the style of graphics programming to be implemented. The formal description of this meta-concept of the system is sketched.Item AN INTERACTIVE RENDERING TECHNIQUE FOR 3-D SHAPES(The Eurographics Association, 1985) KONDO, Kunio; KIMURA, Fumihiko; TAJIMA, Taro; C.E. VandoniThis paper describes an interactive rendering technique for giving an impression of 3-D shapes. The following points are discussed : 1) The classification of continuous tone patterns 2) Methods of drawing pictures to enhance 3-D shapes 3) Rules of rendering for the representation of 3-D shapes. The following results are obtained: The use of the rendering rules and CARP facilitates the clear representation of these characteristics and is proved to be effective in creating a picture in which the shapes of bodies are clearly defined,Item A NORMAL-BUFFER VECTORIZED SURFACE SHADING MODEL(The Eurographics Association, 1985) Curington, Ian J.; C.E. VandoniA surface rendering implementation is described that separates visibility operations from surface shading operations with a Normal-Buffer data structure. This allows for scene complexity independent shading operations at a fixed computational cost per frame. The Normal-Buffer approach also allows the implementation of a fully vectorized surface-shading algorithm when the shading model is applied to each pixel in the scene. The vectorized shader is described using an array processor with a directly attatched frame store in a high performance scene-generation system.Item A GENERALISATION OF THE TIMMER BLENDING FUNCTIONS FOR BEZIER-TYPE CUBIC CURVES(The Eurographics Association, 1985) NTOKO, NZUMBE-MESAPE; C.E. VandoniAlternative blending functions are derived for a Bezier-type cubic curve touching the middle side of its control polygon. Three shape parameters are used which determine the point on the middle side of the control polygon where the curve touches the polygon. It is then shown that the blending functions proposed are generalizations of those proposed by Timmer.Item Configuring Reference Systems for Certifying GKS Implementations(The Eurographics Association, 1985) Gbel, M.; Hbner, W.; C.E. VandoniThe development of test packages for certifying GKS implementations is based on the falsification approach which provides a useful framework in the area of software validation. Although there are different test strategies, most of them follow the method of comparing test results against valid reference data. Comparison can be done either in an automatic way or by human judgement. References used for certifying graphics systems are pictures or data which represent a picture at a particular interface. This paper will outline reference data used for testing GKS implementations at the device interface. Furthermore the process of configuring a GKS reference implementation and it's usage for certifying candidate GKS implementations will be presented in detail.Item PIPELINE APPROACH FOR BUILDING THE PRESENTATION GRAPHICS SYSTEMS(The Eurographics Association, 1985) Klimenko, S.V.; Kochin, V.N.; Samarin, A.V.; C.E. VandoniA pipeline approach is suggested for building up presentation graphics systems from modules performing elementary transformations of graphics objects. Different ways of composing pipelines are discussed which allow the minimal system configuration and the best use of graphics hardware capabilities. It is shown that the pipeline model of a virtual graphics device yields drivers, minimal in size and simple to implementation.Item TABLE LOOK-UP GRAPHlC INTERPOLAT ION(The Eurographics Association, 1985) Alia, G.; Barsi, F.; Martinelli, E.; Tani, N.; C.E. VandoniIn this paper a fast procedure is presented to fairly interpolate a given set of points, which is mainly based on the use of table look-up techniques. Storage amounts required can be easily supplied by present memories technology. Though our procedure can be applied to any interpolation method, it is well suited for a spline, using an angle as a parameter, which was defined by the authors in a previous paper. Benefits and limits of the procedure are discussed and several examples of its behaviour are given.Item MULTI-DIMENSIONAL GRAPHICS(The Eurographics Association, 1985) Inselberg, Alfred; C.E. VandoniItem GENERALIZATION OF CONTOUR TRACKING IN IMAGE SYNTHESIS, AND APPLICATION(The Eurographics Association, 1985) Hegron, Gerard; C.E. VandoniIn this report, we propose to present most of the treatments about convex and nonconvex colored shapes from a data structure of their contour which is the general approach of contour tracking . Contour filling and oblique cross-hatching take advantage of the coherence between adjacent scan lines and adjacent hatching lines. The position of a point with respect to a nonconvex polygon is solved from filling logic, and the clipping of a line segment by a nonconvex polygon uses the slant cross-hatching idea. We present the clipping of the two nonconvex polygon set. From the area filling of non polygonal blobs, contour tracking is generalized to three geometric problems : position of a point, clipping of a line segment and of a circular arc by a non-polygonal contour, Finally, we discuss the general advantages of contour tracking and application in the writing of a text in a nonconvex polygon.Item TOWARDS OBJECT-ORIENTED GRAPHICS STANDARDS(The Eurographics Association, 1985) Wisskirchen, Peter; C.E. VandoniThe introduction of powerful object-oriented systems such as Smalltalk-80 and ZetaLisp Flavors offers a number of potential benefits to the field of computer graphics. This paper examines the potential for marrying object-oriented programming languages to emerging graphics kernel standards definitions. Examples of object-oriented hierarchies of graphics structures are provided, and modifications and extensions to kernel standards are suggested in order to both simplify the standards and more readily embrace the objectoriented approach.Item GRAPHICAL DATA BASES BUILT ON PEANO SPACE-FILLING CURVES(The Eurographics Association, 1985) LAURINI, Robert; C.E. VandoniThis paper is devoted to the applications of Peano spacefilling curves for modelling graphics information. These curves, based on bit interlacing, allow the modelling, easily, of images with quadtrees, solids with octrees and ray casting techniques, colour coding for paint systems, terrains and some kinds of animation in film bases. Finally, Peano keys and space-filling curves appear to be an efficient tool for logical modelling of computer-graphics objects.