Advanced Graphics Research Articles

Distributed graphics: where to draw the lines?

Distributed graphics: where to draw the lines?

MARC-a system for simulation and visualization of space mission scenarios

MARC (modeling, animation, rendering, and compositing), a system using advanced computer graphics and animation techniques for spacecraft mission simulation, is described. The MARC system provides capabilities for generating complex models of both man-made and natural phenomena. The system models orbital dynamics of terrestrial satellites, supports solid models for the Earth, Sun, and Moon, and simulates the dynamics of terrestrial satellites for arbitrary elliptical orbits. A stellar background including magnitudes and spectral types is generated. The elements of the MARC system, including object modeling tools, orbital animation techniques, the rendering system used to compute individual frames, and the compositing techniques used, are discussed. The software architecture of the MARC system and the hardware used to support the system are described. >

Simulated Off-Line Programming of Welding Robots

The objectives of the work described in this paper are to develop and evaluate a method for calculation of interference between objects in a robot welding workstation, to develop a robot trajectory planning technique recognizing interference, inverse kinematics constraints, and welding parameter re quirements, and to demonstrate the trajectory planning tech nique using advanced computer graphics. Workstation mod eling and relevant kinematic relationships are discussed. A method of interference calculation is developed which allows rapid calculation of interference between convex polyhedra using a steepest descent graph search. If desired, exact sepa rating distances and directions can be found. A simple mod ule for automatic selection of welding parameters is de scribed. Interference-free trajectories that do not violate kinematics constraints are found by searching among possi ble inverse kinematic solutions for the desired welding torch trajectory. The above methods have been combined and implemented using interactive graphics in a prototype soft ware package called A UTO WELD.

Visualization of Hydraulically Driven Fracture Propagation in Poroelastic Media Using a Superworkstation

Summary High-performance engineering workstations (HPEW's) provide new opportunities for analyzing complex numerical simulations through the use of innovative visualization techniques. These techniques are applied here to a two-dimensional (2D) fracture propagation in rock, where the rock is assumed to be poroelastic. Understanding of the complex physical interactions between fluid and rock is enhanced when the advanced, three-dimensional (3D) graphics capabilities of such a super-workstation are used. These capabilities are defined and discussed with respect to oilfield-related problems. Introduction HPEW's, also known as superworkstations, have a tremendous potential for exposing complex physical phenomena that otherwise potential for exposing complex physical phenomena that otherwise are difficult to visualize or to comprehend. ["Superworkstation" is defined here as an HPEW with a minimum of 10 million instructions per second (mips) of processing power, 16 or more megabytes of random access memory, several hundred megabytes of disk space, a high-level operating system (such as UNIX), and most importantly, advanced 3D graphics display capabilities supported within the workstation hardware. The workstation should also include a high-definition raster display device or monitor with typically 1,024 × 1,280 pixel resolution. "Superworkstation" has been adopted because it is commonly used by vendors to differentiate these devices from enhanced personal computers and from low-end engineering workstations.] Phenomena associated with oil fields are especially challenging because they often occur at great depths and at scales that cannot be reproduced in the laboratory. Furthermore, these problems are frequently 3D and may involve coupled physical processes-such as mechanical deformation, fracture initiation physical processes-such as mechanical deformation, fracture initiation and propagation, and fluid and heat flow. The need to understand these better has led researchers to rely on numerical simulations. The rapid increase in computer performance and the introduction of supercomputers have made it possible to incorporate extremely complex physical models into numerical simulations. It is now becoming apparent to many researchers that they are limited by their ability to communicate with the computer rather than by the computational power and capabilities of the computer. ("Super-computer" is typically used in reference to computers that can perform on the order of 100 million floating point operations per second. Here we refer to a broader range of computers that have been specially designed for high-performance, scientific computing.) The development of supercomputers has been driven by demands for complex numerical modeling. In turn, the development of superworkstations is driven by a need to comprehend the large amount of scientific data that can be generated by a supercomputer. The superworkstation takes advantage of two important human traits: the ability to recognize patterns in complex arrays of data and the ability to visualize large amounts of data. These concepts have been addressed in a report to the Natl. Science Foundation, which states that "the gigabyte bandwidth of the eye/visual cortex system permits much faster perception of visual relationships than any other mode, making the power of supercomputers more accessible." Although the HPEW initially will be welcomed for its computational speed, we believe that a more significant impact will be the introduction of high-performance, 3D graphics at the engineer's desk. The HPEW allows rapid creation of 3D, solid-colored images and the ability to animate those images. The additional space and time dimensions present tremendous opportunities for grasping time-dependent and coupled processes better. This paper is divided into three principal sections. The next section exemplifies the application of an HPEW to a 2D, coupled simulation of fracture propagation in poroelastic rock. The numerical model accounts for three interrelated physical phenomena: fluid flow in the fracture, deformation of the rock mass, and leakoff in the rock mass. JPT P. 574

The application of advanced CT imaging and computer graphics methods to reconstructive surgery of the hip.

Advanced computed tomographic and computer graphic techniques enhance diagnostic accuracy and offer the means by which three-dimensional operative planning can be achieved. These techniques have been used to diagnose hip pathology, rehearse and evaluate surgical plans, assess postoperative results, and design individualized prostheses.

Teaching introductory and advanced computer graphics using micro-computers

In the past few years there have been significant advances in both the computational and graphics capabilities of micro-computers. In graphics the standard (for the IBM compatible world) has advanced from the Computer Graphics Adapter (CGA) through the Enhanced Graphics Adapter (EGA) to the present Video Graphics Array (VGA). With the multiple color capability of the VGA, images can be constructed which use graphics shading algorithms. This allows us to teach more advanced concepts in introductory courses and even to teach some topics in advanced courses using these machines. In this paper I will discuss how these hardware improvements have allowed for changes in our introductory graphics course and also our experience in teaching an advanced course using these machines.

Requirements for Advanced Graphic Robot Programming Systems

In recent years, several off-line programming and simulation systems have been developed to assist in the planning of new robot applications. Most off-line programming systems allow the user to set up the geometric layout of a work cell. However, in general, only a subset of robot commands is supported by the simulation systems. The Institut für Werkzeugmaschinen und Betriebswissenschaften (iwb) of the Technische Universität München has developed a simulation system, USIS (Universal Simulation System) for task planning and off-line programming of industrial robots. The system allows for the setting up of a “logic layout “of a work cell and supports most common robot programming statements. This paper discusses the requirements for advanced graphic robot programming systems and presents an approach to this problem while describing some features of USIS.

Advanced graphics for visualization of shielding relations

An attribute control scheme for the visualization of shielding relations among 3D objects, not restricted to the inflexible primitive-wise binding and the simple minded hidden parts removal, is presented. It is an important factor in 3D graphics how to visualize shielding relations to help users understand 3D geometry of objects. In almost all graphics systems currently used, shielding relations can be represented only by the hidden line/surface indication of which behavior users cannot control except for the selection from few alternative modes; non-removing, removing, and indicating. Such a restricted treatment is obviously insufficient to generate a wide range of pictures for a variety of user demands. In the scheme proposed here the attributes of the subparts of primitives are determined depending on the shielding environment. The determination procedure is application-user programmable. An experimental system named GRIP which implements this scheme is presented. The integration of a hierarchical structuring into GRIP, which makes it possible to determine attributes depending on the multiple shielding environments, is also described.

Advanced graphics for visualization of shielding relations

Advanced graphics for visualization of shielding relations

The Visualization Roundtable

CIP's panel discussion on visualization in scientific computing contains edited highlights prepared from a series of five individual interviews, conducted by CIP Managing Editor Alexander Wolfe, with Maxine Brown, Associate Director, Electronic Visualization Laboratory, The University of Illinois at Chicago; Donald Greenberg, Director, Program of Computer Graphics, Cornell University; Michael Keeler, Manager, Advanced Graphics Projects, San Diego Supercomputer Center (now with Ardent Computers Inc.); Alvy Ray Smith, Cofounder and Executive Vice President, Pixcar; and Lany Yaeger, Principal Engineer, Vivarium Project, Apple Computer Inc. We believe this discussion is particularly timely in light of the recent publication of Visualization in Scientific Computing, a report to the National Science Foundation by the Panel of Graphics, Image Processing, and Workstations. Round-table participant Smith served on the 16-member Panel; Brown was one of three editors of the ViSC report. In the words of that report, “Visualization in Scientific Computing can bring enormous leverage to bear on scientific productivity and the potential for major scientific breakthroughs, at a level of influence comparable to supercomputers themselves. The Panel recommends a new initiative in Visualization in Scientific Computing, to get visualization tools into the ‘hands and minds’ of scientists.”

Computer graphics curricula: a survey of PhD granting departments

Computer graphics is not a required course of study in the ACM computer science curriculum. Advances in computer graphics technology along with recommendations from SIGGRAPH encourage computer graphics to be required in the computer science curriculum to keep education in step. Ohlson outlines core and advanced elective computer graphics courses and suggests both be offered.A February 1987 survey of computer science PhD granting institutions shows: 1) 97 percent of the institutions already teach one or more computer graphics courses: 59 percent teach two or more courses, 2) courses cover basic and advanced material, 3) a few common textbooks determine course contents and 4) average enrollment is 29. The survey illustrates the prevalence of computer graphics courses and suggests that academic interest warrants its inclusion in future curriculum recommendations. Data from the university survey provides suggested outlines for typical computer graphics courses. Eleven of thirteen publishers answering a February 1987 survey publish or are interested in publishing computer graphics related texts.

Computer graphics techniques and computer-generated movies

The JPL Computer Graphics Laboratory (CGL) has been using advanced computer graphics for more than ten years to simulate space missions and related activities. Applications have ranged from basic computer graphics used interactively to allow engineers to study problems, to sophisticated color graphics used to simulate missions and produce realistic animations and stills for use by NASA and the scientific press. In addition, the CGL did the computer animation for “Cosmos”, a series of general science programs done for Public Television in the United States by Carl Sagan and shown world-wide. The CGL recently completed the computer animation for “The Mechanical Universe”, a series of fifty-two half-hour elementary physics lectures, led by Professor David Goodstein of the California Institute of Technology, and now being shown on Public Television in the US. For this series, the CGL produced more than seven hours of computer animation, averaging approximately eight minutes and thirty seconds of computer animation per half-hour program. Our aim at the JPL Computer Graphics Laboratory (CGL) is the realistic depiction of physical phenomena, that is, we deal primarily in “science education” rather than in scientific research. Of course, our attempts to render physical events realistically often require the development of new capabilities through research or technology advances, but those advances are not our primary goal.

Real-time operational planning for the U.S. air traffic system

This paper describes an integrated planning model for the U.S. air traffic system. The approach incorporates the dual objectives of monitoring collision risk while minimizing transportation costs. Specialized solution algorithms exploit the underlying structure of the model—especially for large-scale examples. The proposed formulation is tested with real-world data for the Indianapolis control sector. Additional experiments with a CRAY X-MP/24 supercomputer show that a full-scale model can be solved under real time conditions. Despite these advances, additional work is required in developing a practical system. Suggestion are made for combining advances in computer graphics and mathematical modeling.

Advanced systems for program appraisal: prospects for General Systems Decision Support centres in the USA

Advances in information technology and systems science are opening up new opportunities for improved decision support systems at the highest levels of the US government. Federal agencies already make extensive use of computer-based decision support, including spreadsheet software, decision analysis models, forecasting techniques and (sometimes) decision conferences and computer conferences. Federal agencies are also increasingly using electronic data bases, remote-sensing data from satellites, advanced computational capability and advanced computer graphics and displays. These developments are rarely integrated together and applied in direct support of top-level agency and government-wide decision-making. Realization of improved top-level decision support could be achieved through a synthesis of technical, informational, and analytical advances utilizing general systems and cybernetics concepts to create what might be called general systems decision support centres or systems (GSDSS). GSDSS could help the...

Colour graphics and three-dimensional scene synthesis in image display

Recent advances in computer graphics have allowed the synthesis of realistic scenes consisting of surfaces and their coverings. This can be exploited in image displays, which provide a powerful way of gaining an appreciation of the spatial nature of scientific data. If data variables are represented by the naturally observed properties of realistic scenes, a better appreciation of the data can be attained. This paper shows how sophisticated colour graphics techniques can be incorporated within an image display system to produce realistic three-dimensional scenes. Examples of coloured surfaces representing geoscientific data are shown, and the value, in a graphics context, of the techniques developed for the display of image data is discussed.

The APL:9SPlus:2E System for the Macintosh: an overview

The APL*PLUS System for the Macintosh™ is a full-featured APL interpreter that integrates the Macintosh user interface style into a standard APL*PLUS System environment. An overview of these Macintosh-specific features along with a comparison of the capacity and performance of the APL*PLUS Mac System to other APL systems suggests that APL applications that are highly interactive, require large workspaces, and need advanced graphics are best implemented on the Macintosh.

Personal computers

The personal computer industry has a short story history which is dominated be a principle of standardization of a rather ad hoc nature. However, due to the enormous sales of personal computers, these standards are commercially more important than those set up by standards organizations. They are, of course, defined by the largest computer company in the world, IBM (International Business Machines). The real-time nature of such a single tasking dedicated processor system will be illustrated by a real example. The history of the IBM-PC began in 1980 with a design which has often been criticized by the computer professionals. The arrival of new models was followed by an enormous commercial success, which took many people, including some in IBM, by total surprise. The major components of the IBM-PC will be described along with its modular and open nature which was a major factor in encouraging third-party developments. The power and weight of the largest computer manufacturer was reinforced by established large and medium producers as well as the, so-called, back garage small companies which gave an artisanal flavour to the industry. Some idea will be given of the range of hardware and software produced as a way of adding value to the industry's successful commercial standard. Another major industry is the production of IBM compatible personal computers. IBM's competition produced clones which faithful copied the original but could be marketed at a lower price. Another successful approach was the production of a superior model where some compatibility would be sacrificed in order to produced enhanced versions at roughly the same price. Enhancements included faster processors, for example the Intel 8086, and better displays. A short review of some contenders will be given. The most notable exception to the trends desccribed above is the Apple Macintosh which is very successful but does not follow the IBM compatible route. While the hardware is radically different from the IBM-PC, one can find similar classes of software running with a completely different user interface. The design of the Macintosh and the range of available software is described and compared with the IBM-PC. New personal computers are still appearing, some of which look quite different from the IBM-PC. There is often an attempt to unite the best of the Macintosh features with the advantages of the IBM-PC. Notable recent personal computers are the Atari ST520 and the Commodore Amiga. The Atari ST520, and now also the Atari ST1040 with larger memory, offer Macintosh style working for a fraction of the Macintosh price. The Amiga offers new facilities for advanced graphics and stereophonic sound which technically put it well ahead of much of the competition. The Commodore company, however, may have overstretched its finances with such an expensive venture. There is another area of personal computing which is covered by the more expensive and more powerful personal workstation. The personal workstations offer fast processing, multi-tasking and excellent networking. Two of the latest entries are the IBM RT-PC and the Apollo DN3000. Both machines run Unix systems and have an AT bus taken from the IBM PC-AT. As well as using the AT bus for connecting peripherals, it is proposed to offer an AT bus card which is a PC and give this ‘PC on a card’ access to the hardware of the personal workstation. This is an interesting switch since, instead of the bus being inserted into the personal computer, the personal computer is inserted into the bus.

PC's as Graphics Stations for the New TRIUMF Vax-Based Data Acquisition and Analysis System

The requirements of fast graphics display and low impact on the data acquisition and analysis system (DAAS) VAX host prompted TRIUMF to adopt PC's on an ethernet as graphics workstations for the new VAX-based DAAS. This multiprocessor solution provides for high speed host to workstation data transfer for image display, and independence of the host's CPU loading for the provision of advanced graphics services such as image storage, replotting, image-data transformations, peak fitting, statistics calculations, comparison of stored images etc.

Combining physical and visual simulation—creation of the planet Jupiter for the film “2010”

By integrating physical simulation, in the form of numerical fluid dynamics, with visual simulation, in the form of particle rendering, texture mapping and traditional polygonal modeling techniques, we have achieved a uniquely realistic and organic special effects sequence of a planetary atmospheric flow. This paper examines the selection, implementation, and application of these techniques, know collectively as VORTEX, to produce the moving images of the planet Jupiter in the film "2010." Details of the generation of the flow field and the fluid dynamic algorithms employed are presented, along with issues relating to the generation and updating of the atmospheric images. We also describe the integration of these techniques with an advanced computer graphics imaging system. The VORTEX system provides a fairly general solution to a class of imaging problems involving two-dimensional fluid flows, and we remark upon its application to other projects. VORTEX, as an example of the marriage of physical simulation to visual simulation, demonstrates the importance of computer graphics to the computational sciences and of the physical sciences to the field of computer graphics.

A message passing approach to robot programming

We are developing a communication oriented interactive environment for robot programming. A set of independent software modules for robot motoring control, low level sensoring processing, kinematics simulation and world model construction has been implemented as separate tools. They have been merged in a software environment whose implementation is based on the operating system Accent and can be accessed through an advanced graphics workstation. Each module interacts with the others through message exchange; each module may be organized into new submodules as new operational behaviours belonging to its functional area become necessary.