Abstract: An organization of interaction techniques, based on the user tasks for which the techniques are used, is proposed. It is suggested that task requirements limit the set of techniques that can be considered for a particular application. The characteristics of a variety of techniques are enumerated and many of the considerations important to their effectiveness are discussed. Relevant experimental and experiential comparisons are tabulated.

Abstract: An offset capability for planar curves and profiles in a solid modeler leads to the solution of some practical design problems.

Abstract: Low-cost PCs and workstations with bit-mapped graphics possess limited processing power. As a result, efficient algorithms are needed to draw curves interactively.

Abstract: Some broad principles for the effective use of color are established on the basis of the mechanisms of human color perception. Some functional relationships that should improve the visual effectiveness of color display are derived.

Abstract: A simple and systematic method is described for calculating the integral of a polynomial function over an arbitrary nonconvex polyhedron. First a general formula is presented for direct evaluation of the integral of a polynomial over a 3-D simplex. An integral over a polyhedron can then be easily calculated by using the central projection method and decomposing a polyhedron symmetrically into a set of simplices and accumulating the results from each simplex based on this formula. This method adopts a systematic and automatic decomposition. It is analytically exact, but the practical accuracy of the result is within the accuracy of floating-point arithmetic. Furthermore, the time complexity of this method is linearly proportional to the number of vertices of a polyhedron.

Abstract: In this approach, the parametric form is applied without the usual computational nightmare. The key is to view the parametric range as an interval, relying on subdivision algorithms.

Abstract: For realistic simulation it is necessary to thoroughly define and describe light-source characteristics?especially the light-source geometry and the luminous intensity distribution.

Abstract: Sapphire (the Screen Allocation Package Providing Helpful Icons and Rectangular Environments) is a powerful window manager running on the PERQ personal workstation. Following some background material, the author provides a tutorial on Sapphire's screen allocation package, focusing on its icons and user commands. The icons in Sapphire are intended to enhance the user's productivity when executing multiple tasks concurrently. Therefore, they present six pieces of information about the process being run, as well as two pieces of information about the status of the window. Thus, the user can easily tell whether the process running in the window has an error or wants attention and what percentage of the task has been completed. The user interface provides full functionality from both the pointing device and the keyboard and is easy for the novice while providing simple and powerful operations for experts. All commands are available from pop-up menus, but accelerators allow the most common commands to be executed with a single button press. The picture in the tracking symbol changes to show the operation that will be performed. This user interface promotes experimentation, since there is always appropriate feedback, and it is always possible to abort an operation once it has been started.

Abstract: Many challenges must be faced before an automatic process-planning system will be practical for individual application?specifically, the recognition and simulation of a part's ?form features.?

Abstract: The design of the user interface management system (UIMS) is discussed within the context of the problems that it is intended to solve. The aim is not to review the various forms and strategies that have been proposed and used for UIMS development but rather to clarify the environment of a UIMS. The issues, which relate the services of a UIMS to the applications that it is intended to support, range along a continuum from the keystroke/transaction level, or micro level, to the macro level of integration across an entire application environment. Three examples are presented to illustrate the range of this continuum and the issues that arise at each level.

Abstract: A new computer graphics technique generates complicated random textures, like those found on natural objects. Requiring little data, it allows easy control of textural properties.

Abstract: The features and organization of a hardware architecture that is designed to facilitate the real-time display and manipulation of a single three-dimensional object on a raster-scan video display are briefly summarized. The author then outlines the major features of an extension to the architecture that will permit the high-speed display and manipulation of multiple, independent, shaded three-dimensional objects represented as a voxel (volume-element) database with gray scale. The objective is to provide many useful capabilities at or near video rates facilitating extensive real-time interaction. The architecture is highly modular, permitting a cost tradeoff to be made to achieve a given level of performance. It also includes a great deal of regularity in its structure, making it directly suitable for VLSI implementation. A key feature is that no computational operations more complex than adds, shifts, and comparisons are required in real time. The display characteristics for each object are controlled by a concise object descriptor table, which contains all of the control parameters required to process that object.

Abstract: The overall feasibility of 3-D imaging for intracranial soft tissues depends on three vital areas: the display method,the display options, and the image processing system.

Abstract: This tutorial examines the origin and nature of the problem of contention for memory cycles?a problem that impacts the image update performance of every raster graphics system.

Abstract: Improved techniques of surface interpolation, clipping, and hidden-surface elimination help solve some problems in generating perspective views of digital terrain data.

Abstract: Properly establishing the relation between linear algebra and geometry makes it easier to obtain the three-by-three orthogonal matrix that describes a specified rotation.

Abstract: Users of interactive CAD systems who are trying to cope with the hidden-surface visualization problem will want to investigate this new algorithm.

Abstract: In advanced CAD/CAM applications, designers need the capability of modeling solid objects with complex surfaces. This geometric modeler incoroorates new techniques to combine design functions.

Abstract: This algorithm exploits basic differential geometry analysis to achieve high speed,low memory usage,reliability, and independence from surface type.

Abstract: The term corporate identity program is well-known in the graphic design field, which has applied the approach to the traditional areas of stationery, vehicle identification, signage, and other forms of complex communication. It is argued that this approach should be extended to the design of screens, especially for high-resolution, iconic, multiwindow interfaces. Typography, symbolism, and color are discussed from this perspective, and three case studies, namely, the Xerox Star, the Apple Lisa, and the Intran Metaform system, are examined.

Abstract: This preliminary report presents an algorithm for automatically generating from an octree description the data that a computerized numerical control milling machine requires to manufacture a part.

Abstract: The principles of good visual design used in advertising can help programmers design effective computer displays that will substantially improve the man-machine interface.

Abstract: The cluster architecture allows resource sharing by up to 16 users and takes advantage of today's LSI technology to achieve high throughput at reasonable costs.

Abstract: Capable of displaying 10,000 polygons per second, this interactive terminal produces smooth, color-shaded surfaces quickly for applications in science, engineering, training simulation, and animation.

Abstract: A new method for numerically computing the intersection of implicitly defined surfaces provides the capability to display intersections that are impossible to find analytically.

Abstract: Fifth-generation computers will probably be based on logic programming languages like Prolog rather than on Fortran-type languages. Are such languages suitable to 3-D CAD applications?

Abstract: The Domain system's objective is to integrate mainframe capability with local area networking and raster graphics capabilities at a cost appropriate to engineering and graphics applications.

Abstract: Faster solutions to 3-D visibility problems and better distribution of multiprocessor systems can be achieved when this new connectivity data algorithm is used.

Abstract: Complex combinations of text, graphics, and alphanumeric strings can be manipulated easily and rapidly when displayed in screen formats similar to conventional hard-copy forms.