We consider the problem of converting boundary representations of polyhedral objects into constructive-solid-geometry (CSG) representations. The CSG representations for a polyhedron P are based on the half-spaces supp...
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We consider the problem of converting boundary representations of polyhedral objects into constructive-solid-geometry (CSG) representations. The CSG representations for a polyhedron P are based on the half-spaces supporting the faces of P. For certain kinds of polyhedra this problem is equivalent to the corresponding problem for simple polygons in the plane. We give a new proof that the interior of each simple polygon can be represented by a monotone Boolean formula based on the half-planes supporting the sides of the polygon and using each such half-plane only once. Our contribution is an efficient and practical O(n log n) algorithm for doing this boundary-to-CSG conversion for a simple polygon of n sides. We also prove that such formulae do not always exist for general polyhedra in three dimensions.
Designing a complex system such as a control, automation or electronic system most engineering activities involve graphical representations for the different design and modelling stages. Starting the design cycle the ...
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Designing a complex system such as a control, automation or electronic system most engineering activities involve graphical representations for the different design and modelling stages. Starting the design cycle the structure and function of the system has to be specified. For the ease of imagination and decision the difficult interrelations between system components and subfunctions are frequently depicted by graphical schematics and diagrams. In this paper we introduce the idea and basic functions of a general purpose computer Aided Schematics (CAS) system, that may assist efficiently all schematics-based processes ranging from interactive to completely automatic drawing including the interfaces to further data processing. We discuss the benefits of the CAS approach as rapid generation and updating of correct and consistent graphics and its impact on the whole design and documentation cycle. Furthermore, some of the intricate, mainly graphtheoretical optimization problems inherent in the computer generated layout of schematic drawings are addressed. Finally, we outline the possible application of CAS techniques to different engineering disciplines, where graphical programming and documentation of programmable controllers (PC’s) is believed to be a profitable domain. First encouraging experience in the automatic documentation of complex control programs is reported on.
A behavioral and logic simulation system which uses extensive optimization and compilation techniques to obtain high performance is described. It incorporates data-flow analysis to optimize the evaluation of unordered...
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A behavioral and logic simulation system which uses extensive optimization and compilation techniques to obtain high performance is described. It incorporates data-flow analysis to optimize the evaluation of unordered assignment statements that define a hardware structure, and to extract clocking rules. An integral code generator produces efficient assembly code for three different machines, and an associated run-time library provides a flexible interactive debugging environment.< >
Trimmed non-uniform rational B-splines have become a very useful surface representation form in the mechanical CAD industry. Previous rendering methods use the de Boor algorithm to evaluate the surface at equal increm...
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Trimmed non-uniform rational B-splines have become a very useful surface representation form in the mechanical CAD industry. Previous rendering methods use the de Boor algorithm to evaluate the surface at equal increments in parameter space. This yields polygons which are then rendered. Alternatively the Oslo algorithm and Boehm's knot insertion algorithms are used in a subdivision approach. A new method is presented for rendering trimmed NURB surfaces of arbitrary order using the adaptive forward differencing (AFD) technique. This method extends the AFD technique to higher order, efficiently computes the basis matrix for each span, calculates the shading approximation functions for rational surfaces, and trims and image maps NURB surfaces. Trimming is accomplished by using AFD to scan convert the trimming curves in parameter space, thus producing the intersection points between the trim curves and an isoparametric curve across the surface. A winding rule is used to determine the regions bounded by the curve which are then rendered with AFD. The method is suitable for both hardware and software implementations;however, higher order surfaces require high precision due to the forward difference nature of the algorithm.
A concept for a software support system for the development of airborne graphics software is described. The advent of the CRT in cockpits and the current trend toward complex pictorial formats has caused a significant...
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A concept for a software support system for the development of airborne graphics software is described. The advent of the CRT in cockpits and the current trend toward complex pictorial formats has caused a significant increase in the amount of graphics software on board the aircraft. However, current software development tools relies on techniques that do not lend themselves to digital graphics. The software support system discussed provides several key items. An interactive workstation allows the designer to essentially draw the desired image and specify the dynamic attributes. A code generation system then creates hardware independent source code. A targetting compiler section creates hardware specific code and also modifies existing system code to accept the new graphics module. This automated system concept not only supports the initial graphics software creation but also supports the software maintenance of fielded systems. The system allows rapid production of software and significantly reduces the software skills required of the user.< >
A behavioral and logic simulation system which uses extensive optimization and compilation techniques to obtain high performance is described. It incorporates data flow analysis to optimize the evaluation of unordered...
ISBN:
(纸本)9780818688645
A behavioral and logic simulation system which uses extensive optimization and compilation techniques to obtain high performance is described. It incorporates data flow analysis to optimize the evaluation of unordered assignment statement that define a hardware structure, and extract clocking rules. An integral code generator produces efficient assembly code for three different machines, and an associated run-time library provides a flexible interactive debugging environment.
This paper presents rendering techniques that use volumes as the basic geometric primitives. It defines data structures composed of numerous subvolumes, in excess of 100,000. Over each subvolume, a scalar field descri...
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ISBN:
(纸本)9780897912754
This paper presents rendering techniques that use volumes as the basic geometric primitives. It defines data structures composed of numerous subvolumes, in excess of 100,000. Over each subvolume, a scalar field describes the variation of some physical quantity. The two rendering methods described herein assume a trilinear variation of this scalar field within each volume element, unlike voxel-based techniques that assume a constant value for each subvolume. The result is a higher order approximation of the structures within the volume. In addition, solid texture mapping, atmospheric attenuation, and transfer functions relating the dynamic range of the scalar field to color and opacity are used to isolate important data features. The result is a new method for the visualization of three-dimensional data resulting from numerical simulations and observations of natural phenomena. This method continuously covers the gap between surface-based and voxel-based techniques.
A formulation of the cable plant design problem using artificial intelligence and expert system techniques is described. The knowledge of the design engineer is captured in an interactive expert system. Such an expert...
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A formulation of the cable plant design problem using artificial intelligence and expert system techniques is described. The knowledge of the design engineer is captured in an interactive expert system. Such an expert system has been designed and implemented to provide the network designer with a tool to design the broadband cable plant. The design includes the knowledge representation for the cable plant components and design rules. The system is coded in Turbo PROLOG and executes on an IBM PC. The functional expert system parts include a user interface, inference engine and control, design knowledge base and graphics system. A user can provide an initial problem file or modify an existing one.< >
The Theater War Exercise (TWX) is a computer-assisted, theater level airpower employment exercise conducted by the Air Force Wargaming Center. Its primary purpose is to give senior level military officers a feel for t...
ISBN:
(纸本)9780911801422
The Theater War Exercise (TWX) is a computer-assisted, theater level airpower employment exercise conducted by the Air Force Wargaming Center. Its primary purpose is to give senior level military officers a feel for the intricacies of high level decision-making in a combined air/land conventional warfare situation. Until recently, output from TWX consisted of a large number of tabular hard-copy reports which were difficult to understand and cumbersome to use. This paper discusses the development of a map-based graphical interface to TWX which provides a much more user-friendly interface to the information and provides a baseline for the development of new techniques for user interaction with the exercise. The methodology and toolset developed for this project are of particular interest because of their applicability to a wide variety of other wargaming and simulation systems.
Current affordable architectures for high-speed display of shaded 3D objects operate orders of magnitude too slowly. Recent advances in floating point chip technology have outpaced polygon fill time, making the memory...
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ISBN:
(纸本)9780897912754
Current affordable architectures for high-speed display of shaded 3D objects operate orders of magnitude too slowly. Recent advances in floating point chip technology have outpaced polygon fill time, making the memory access bottleneck between the drawing processor and the frame buffer the most significant factor to be accelerated. Massively parallel VLSI system have the potential to bypass this bottleneck, but to date only at very high cost. We describe a new more affordable VLSI solution. A pipeline of triangle processors rasterizes the geometry, then a further pipeline of shading processors applies Phong shading with multiple light sources. The triangle processor pipeline performs 100 billion additions per second, and the shading pipeline performs two billion multiplies per second. This allows 3D graphics systems to be built capable of displaying more than one million triangles per second. We show the results of an anti-aliasing technique, and discuss extensions to texture mapping, shadows, and environment maps.
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