bluuebunny/crossref_metadata_2025 huggingface dataset:
An interactive graphics application to advanced aircraft design
Authors: Bouquet D. L.
Published: November 2005

Throughout the 50's, 60's and now the 70's, computer usage has continually been on the increase and, from all indications, this trend will continue in the future. Early computer application programs were run by “computer experts” with the engineers interfacing with the programmers to get their “batch” program run. With the advent of the remote access terminals a more efficient and direct interface to the computer was made available to the engineer-user. More recently the introduction of the storage tube and refreshed tube CRT's linked to computers has now provided the engineers with a graphic interface that is even more direct, and hopefully, more efficient. This introduction of computer-graphics resulted in a proliferation of graphics programs in the aerospace industry. Soon most of the analytically oriented specialities (e.g. Aero-dynamics, Structures, Loads, etc. ) were boasting of powerful graphics programs to assist them to more effectively perform their functions.
The development of three-dimensional spatial modeling techniques for the construction planning of nuclear power plants
Authors: Borkin Harold J. , McIntosh Jonn F. , Turner James A.
Published: November 2005

The results are presented of the first phase of a research project on the application of spatial modeling techniques to the process of planning and executing the construction of a nuclear power plant. A computer modeling technique, based on sets of polyhedra and spatial operations, was developed and applied to modeling the components of a nuclear power plant. The objectives of the modeling are: to store and retrieve information about the various systems in the facility; to produce drawings of those systems from any angle in differing amounts of detail; to aid in the search for interference among the parts of the plant by identifying those elements that occupy the same space or are too close to each other; to calculate information such as surface area, length, and volume of selected elements of the plant; and to aid in finding the optimum construction sequence by simulated construction of selected areas of the plant. Computer techniques are described for inputting information by digitizing directly from engineering drawings, for editing the spatial model, for management of the spatial and non-spatial data, and for graphic output from the model. The software is implemented on the University's central time-sharing computer system and on a mini-computer system in the Architectural Research Laboratory.
Dynamic graphics using quasi parallelism
Authors: Kahn Kenneth M. , Hewitt Carl
Published: November 2005

Dynamic computer graphics is best represented as several processes operating in parallel. Full parallel processing, however, entails much complex mechanism making it difficult to write simple, intuitive programs for generating computer animation. What is presented in this paper is a simple means of attaining the appearance of parallelism and the ability to program the graphics in a conceptually parallel fashion without the complexity of a more general parallel mechanism. Each entity on the display screen can be independently programmed to move, turn, change size, color or shape and to interact with other entities.

The scheme presented herein begins with the notion of a quantum of time, or
tick
, within which there are no ordering constraints on events. Each entity or actor decides what it must do upon the next tick. Ticks are a powerful means of controlling parallel processes but are usually at too low a conceptual level for user convenience. Higher-level operations built upon the tick mechanism are presented, most notably the ability to instruct any entity or group of entities to gradually change or move at a rate that is itself changeable by the same operation. To illustrate these ideas a simple celestial mechanics simulation is presented. Upon each tick the velocities and positions of the objects are updated by the gravitational and propulsive forces acting upon them.

Ticks are only one product of an object-oriented programming style. For the best control and the most modularity, graphics programming should be object oriented. Each object displayed, and its parts, should be independently programable. Instead of being passive data, objects should be responsible for the changes in their position or appearance. Instead of a global controller, each object should interact with the others.
ECOSITE
Authors: Mallary Robert , Ferraro Michael
Published: November 2005

Surface mining, though an efficient method of extracting near-surface coal for the nation's mounting energy needs, requires sound reclamation if the harmful environmental impacts of the method are to be held to a tolerable minimum. Another important requirement is aesthetic quality, a feature which should, but as yet does not, involve professional planners and designers at the early preplanning stage of reclamation. To encourage this needed improvement a multidisciplinary research group at the University of Massachusetts is developing a comprehensive "preplanning-and-design resource package" that includes an interactive graphics program
for landform
design as an important component. Called ECOSITE, this user-oriented program is the first serious effort to apply the power of interactive graphics and CAD to the design and sculpturing of large-scale topographical compositions for reclamation and other forms of site preparation and improvement. This paper discusses the program from the standpoint of its application, specifications, design, current capabilities and necessary improvements, including the ability to test its own output against relevant criteria.
Graphical pre- and post-processor for 2-dimensional finite element method programs
Authors: Tracy Fred T.
Published: November 2005

This paper describes a two-dimensional interactive graphics pre- and post-processor system developed at the U. S. Army Engineer Waterways Experiment Station (WES) for the finite element method (FEM). The paper describes advantages of the data structure of the package and new algorithms developed for grid generation and analysis output display. The programs are developed especially for a time-sharing system (Honeywell G-635) to be used on a storage tube type terminal (Tektronix 4012 or 4014). Programming techniques used to counter the lack of immediate response on such a system are also discussed.
GPGS
Authors: Caruthers L. C. , van den Bos J. , van Dam A.
Published: November 2005

GPGS is a subroutine package offering powerful and versatile support for passive and interactive vector graphics, for time-sharing, batch, and stand-alone minicomputer systems. The package is computer, language, and operating system, as well as display device independent. Its key purpose is to allow for transportabiliit of programs and programmers by providing easy to learn, high level features. The applications programmer writes his program once and then executes it on any supported graphics equipment without recompiling or relinking it. Device-independence was implemented by dividing GPGS into a device-independent part invoked by the applications programmer, and internal, "device drivers", one per display device. Like the GSPC "Core System" whose design it influenced, GPGS is a general purpose package. It has a subset of graphics facilities to handle output of line and character primitives with attributes such as line style and character size, and input from interaction tools such as lightpens, keyboards, valuators, and function keys. It also supports 2D and 3D viewin transformationss for clipping and window to viewport mapping, and coordinate transformations.Unlike the GSPC Core System, GPGS also includes a set of basic features for modelling objects which allows definition of device independent masters called seudo picture segment. These are distinguished from normal, device (DPU) dependent pictur segments into which primitives and their attribute-value settings are ordinarily compiled. These masters may be instanced subject to affine transformations (translate, rotate, and scale) to create a typical master-instance hierarchy. The hierarchy may be stored in a disk based library or compiled into a normal picture segment for output to a display device.The images of objects stored in device dependent picture segments may be transformed on the display surface by v port (image) transformations. These typically allow use of hardware transformation capabilities for dragging or tumbling object images.Host/satellite graphics is accommodated by having the device independent part of GPGS in the host and splitting the device drivers across host and satellite. At the source code level it therefore makes no difference on which.configuration a program will be executed.Among the existing implementations are versions written in assembler for the IB 360/370 and the PDP 11, in both stand-alone and satellite mode, and under a variety of operating systems. They support plotters, storage tubes, and high performance refresh displays. FORTRAN based implementations exist for the Univac 1108, the PDP 10, and a Harris minicomputer.
A Fortran IV program to draw enhanced graphic characters
Authors: Wolcott N. M. , McCrackin F. L.
Published: November 2005

A FORTRAN subroutine SYMBEL is described which enables the drawing of the enhanced graphic characters of Dr. A. V. Hershey on any digital plotting device. Output is by linkage to an external subroutine PLOT. The program operates on any computer with integer binary arithmetic and at least a 30 bit word length.
Machine-independent metacode translation
Authors: Wright Thomas
Published: November 2005

Many systems implement plotter device-independent computer graphics by having a system plot package which outputs a plotter-independent code (here called metacode) and having a translating driver for each plotter which uses this code as input. The translator for this code can often be run with greatest efficiency on the computer which hosts the plotter. In NCAR's configuration, various computers will drive different plotters, making a portable metacode translator a desirable tool. Constructing a metacode translator which can drive the simplest devices and yet provide the potential to use sophisticated plotter hardware features is a stimulating challenge. The design and implementation of such a translator are described.
Line generation for incremental and raster devices
Authors: Earnshaw R. A.
Published: November 2005

The characteristics,properties and generative sequences of line generation algorithms for incremental and raster devices are summarized and the mappings from one into the other are discussed. Extensions to the basic algorithms to exploit a greater variety of possible operations in the basic hardware set of incremental devices and also to cater for various types of curve are summarized.A new method of partitioning based upon derived code sequences and code patterns is presented and is shown to lead to significant code sequence compression (more than 40%) in the majority of cases, and more importantly a significant overall reduction of between 20% and 43% in the total central processor usage. Algorithms for encoding the sequences are presented.
General clipping on an oblique viewing frustrum
Authors: Puk Richard F.
Published: November 2005

An algorithm is presented which clips on a non-rotated viewport positioned anywhere on the viewport plane relative to the viewing vector. This is a generalization of the traditional three-dimensional clipping algorithm in which the viewing vector intersects the viewport at its center. This traditional algorithm is shown to be a special case of the general algorithm. Also shown is that both orthogonal box clipping and perspective pyramid clipping can be accomplished using the same algorithm with only a slight increase in complexity. Finally, the ability to perform switch-controlled hither and yon plane clipping is described. It should be noted that with this general clipping algorithm no separate clipping operation is required for two-dimensional operations since they can be handled as an orthogonal projection from an arbitrary default Z-plane onto the viewport plane.
Automated display techniques for linear graphs
Authors: Maguire R. Brien
Published: November 2005

The development of display procedures for drawing pictures of linear graphs is described. The facility to model relationships pictorially has led to the use of graph theoretic techniques in many different applications. While computers normally work with a numeric representation of a graph such as its incidence matrix, manual transformation of such representations into pictures is a tedious process. An interactive graphics system has been developed which, through a combination of heuristic techniques and semi-automatic procedures, creates visual representations of graphs with a minimum of user intervention. The resultant pictures display mirror-image and rotational symmetries that occur within the graph. This very general approach of displaying symmetry in graphs has proven useful in studies of several classes of graphs. However, the system is primarily a research tool designed for use by mathematicians and graph theorists. Difficulties entailed in adapting the display procedures to more specific application areas are discussed.
Interactive skeleton techniques for enhancing motion dynamics in key frame animation
Authors: Burtnyk N. , Wein M.
Published: November 2005

A significant increase in the capability for controlling motion dynamics in key frame animation is achieved through skeleton control. This technique allows an animator to develop a complex motion sequence by animating a stick figure representation of an image. This control sequence is then used to drive an image sequence through the same movement. The simplicity of the stick figure image encourages a high level of interaction during the design stage. Its compatibility with the basic key frame animation technique permits skeleton control to be applied selectively to only those components of a composite image sequence that require enhancement.
Recognition of three-dimensional objects from orthographic views
Authors: Lafue Gilles
Published: November 2005

This paper presents a program interpreting orthographic drawings input through a digitizing tablet into three-dimensional (3-D) objects. Ambiguity arises in such a task not only in the case of two views but also with three-view inputs, due to coinciding projections of vertices. The main effort consists in heuristically reducing this ambiguity. The general strategy is a bottom-up identification of the objects starting with the tablet-coordinates and aggregating them into vertices, then faces and finally polyhedra. The program does not contain any high level geometrical concepts or probable properties of 3-D objects but only some basic definitions of polyhedra (as expressed by Euler and Mobius). By applying these definitions to different parts of the scene to recognize, it defines local sets of alternatives and then chooses the right ones by running a mini theorem prover over these sets. A major issue in writing this program has been to limit the drawing constraints imposed on the user. In case that it gets blocked in the recognition process, however, the program can require the user's help.
Graphics for social scientists
Authors: Schneider Edward J. , Barge Sylvia , Marks Gregory A.
Published: November 2005

The social science computing environment and the implications of this for the developers of computer graphics is described. Graphic software developed for social scientists at the University of Michigan is illustrated. MULTIGROUP is used to generate displays in the process of data analysis. GRAPH is used to report results to others. A graphical editor is employed to customize displays.
A mobile remote data collection and graphics display station
Authors: Miles John G.
Published: November 2005

A low cost graphic and data collection facility consisting of a storage tube display, plotter, digital multimeter, floppy disc, calculator and BCD instrumentation interface has been built into a single, mobile unit. Laboratory data may be collected automatically by recording the output of the low speed digital multimeter or medium speed BCD DMA interface in calculator memory and then buffering the data to either floppy disc or tape cassette. The data can be summarized and displayed immediately on the CRT or plotter by the calculator using programs available on a floppy disc resident library. Alternatively, the data can be routed to one of two timesharing computer systems at speeds up to 9600 baud where 2-D and 3-D software packages and large application libraries can be used to construct more sophisticated displays for presentation interactively on the CRT. Various applications appropriate to a university environment are discussed. A similar facility at the Sacramento offices of the Army Corps of Engineers used for flood information reporting is also described.
Configurable applications for satellite graphics
Authors: Hamlin Griffith
Published: November 2005

This paper advocates a configurable approach to software for satellite graphics in which the division of labor between the host and satellite computers can be easily changed after an application program has been written. A software system, CAGES (Configurable Applications for Graphics Employing Satellites), implements this approach. CAGES can substantially simplify the application programmer's task of programming a host and satellite computer by making the intercomputer interface relatively invisible to him, while at the same time allowing him the efficiency and flexibility that can result from direct application programming of the satellite computer.Proper design of configurable programs is facilitated by a mathematical model defining a pairwise measure of program module inter-dependence. Experience with this model has resulted in a set of programming guidelines that further aid the application programmer in producing a suitable program structure.
PRIMS
Authors: Hadlock F.
Published: November 2005

PRIMS is an interactive system to be used in the layout of hybrid circuits. The layout involves positioning integrated circuit chips and resistors on a substrate surface. Conducting paths are then defined in order to make interconnections between chips, external connection pads positioned around the edge of the substrate, etc.PRIMS is actually a language which includes commands for defining regions corresponding to integrated circuit chips, and for causing the system to define a tree of conducting paths to interconnect a set of points. There are also commands for displaying a partial layout, for editing the layout, and for generating plotter code for the final layout.
The impact of graphics standards an American point of view (Panel Session)
Authors: Wright Tom , Reed Theodore , Shuey David , Cohen Bruce , Smith Bradford M. , Straayer David H.
Published: November 2005

This panel session will consist of reports from participants in the effort to standardize computer graphics functions in America. There are two principal goals. The first is to provide status reports for the groups represented by the panelists. The second is to explain relationships between different standardization efforts.
A Metafile for efficient sequential and random display of graphics
Authors: Reed Theodore N.
Published: November 2005

Graphics metafiles have been in use at the Los Alamos National Laboratory since early 1977. The first metafile format was defined in 1976 and has been updated several times to allow efficient graphics support in the Los Alamos computing environment. History and current applications of the Common Graphics System (CGS) Metafile are given. Design objectives, details of the format, and random access extensions incorporated in the Metafile are described.
Creating volume models from edge-vertex graphs
Authors: Hanrahan Patrick M.
Published: November 2005

The design of complex geometric models has been and will continue to be one of the limiting factors in computer graphics. A careful enumeration of the properties of topologically correct models, so that they may be automatically enforced, can greatly speed this process. An example of the problems inherent in these methods is the “wire frame” problem, the automatic generation of a volume model from an edge-vertex graph. The solution to this problem has many useful applications in geometric modelling and scene recognition.

This paper shows that the “wire frame” problem is equivalent to finding the embedding of a graph on a closed orientable surface. Such an embedding satisfies all the topological properties of physical volumes. Unfortunately graphical embeddings are not necessarily unique. But when we restrict the embedding surface so that it is equivalent to a sphere, and require that the input graph be three-connected, the resulting object is unique. Given these restrictions there exists a linear time algorithm to automatically convert the “wire frame” to the winged edge representation, a very powerful data structure. Applications of this algorithm are discussed and several examples shown.
Path specification and path coherence
Authors: Shelley Kim L. , Greenberg Donald P.
Published: November 2005

This paper presents an interactive method for specifying a path in space and time through a three-dimensional environment. A sequence is generated by showing the series of views along the path. The sequence is previewed on a vector scope, and after it is interactively refined, each frame is rendered on a raster device. The path is represented by a B-spline to provide smooth, continuous motion. The timing along the path is also defined by a B-spline so that changes in velocity are smooth. The use of “path coherence” is introduced. The utilization of the available data from the a priori temporal and spatial path definition holds great promise for frame to frame coherence. The path coherence can be used to reduce the number of polygons which need to be considered in a viewed environment. This reduction makes the previewing of complex environments appear less cluttered. Furthermore, the computational expense of the culling and sorting operations in the visible line/surface determination is reduced. One sample usage of this is a tree-structured partitioned environment where the priority ordering of the environment must be changed only when the path crosses a partition boundary.
A generalization of algebraic surface drawing
Authors: Blinn James F.
Published: November 2005

The mathematical description of three dimensional surfaces usually falls in one of two classifications: parametric and algebraic. The form is defined as all points which satisfy some equation: F(x,y,z)=0. This form is ideally suited for image space shaded picture drawing, the pixel coordinates are substituted for x and y and the equation is solved for z. Algorithms for drawing such objects have been developed primarily for first and second order polynomial functions. This paper presents a new algorithm applicable to other functional forms, in particular to the summation of several gaussian density distributions. The algorithm was created to model electron density maps of molecular structures but can be used for other artistically interesting shapes.
Filtering edges for gray-scale displays
Authors: Gupta Satish , Sproull Robert F.
Published: November 2005

While simple line-drawing techniques produce “jagged” lines on raster images, more complex anti-aliasing, or filtering, techniques use gray-scale to give the appearance of smooth lines and edges. Unfortunately, these techniques are not frequently used because filtering is thought to require considerable computation. This paper presents a simple algorithm that can be used to draw filtered lines; the inner loop is a variant of the Bresenham point-plotting algorithm. The algorithm uses table lookup to reduce the computation required for filtering. Simple variations of the algorithm can be used to draw lines with different thicknesses and to smooth edges of polygons.
Filtering high quality text for display on raster scan devices
Authors: Kajiya J. , Ullner M.
Published: November 2005

Recently several investigators have studied the problem of displaying text characters on grey level raster scan displays. Despite arguments suggesting that grey level displays are equivalent to very high resolution bitmaps, the performance of grey level displays has been disappointing. This paper will show that much of the problem can be traced to inappropriate antialiasing procedures. Instead of the classical (sin x)/x filter, the situation calls for a filter with characteristics matched both to the nature of display on CRTs and to the human visual system. We give examples to illustrate the problems of the existing methods and the advantages of the new methods. Although the techniques are described in terms of text, the results have application to the general antialiasing problem—at least in theory if not in practice.
Shading of regions on vector display devises
Authors: Lee D. T.
Published: November 2005

Given an arbitrary simple polygon with N vertices we present an algorithm for shading the interior of the polygon with a set of parallel lines where the slope and the distance between lines are prespecified. If the number of shading line segments is M, the algorithm described in the paper runs in 0(N log N + M) time. The algorithm is generalizable to shade any region or regions of an arbitrary planar subdivision.
Merging and transformation of raster images for cartoon animation
Authors: Wallace Bruce A.
Published: November 2005

The task of assembling drawings and backgrounds together for each frame of an animated sequence has always been a tedious undertaking using conventional animation camera stands and has contributed to the high cost of animation production. In addition, the physical limitations that these camera stands place on the manipulation of the individual artwork levels restricts the total image-making possibilities afforded by traditional cartoon animation. Documents containing all frame assembly information must also be maintained.

This paper presents several computer methods for assisting in the production of cartoon animation, both to reduce expense and to improve the overall quality.

Merging is the process of combining levels of artwork into a final composite frame using digital computer graphics. The term “level” refers to a single painted drawing (cel) or background. A method for the simulation of any hypothetical animation camera set-up is introduced. A technique is presented for reducing the total number of merges by retaining merged groups consisting of individual levels which do not change over successive frames. Lastly, a sequence-editing system which controls precise definition of an animated sequence, is described. Also discussed is the actual method for merging any two adjacent levels and several computational and storage optimizations to speed the process.
A method of interactive visualization of CAD surface models on a color video display
Authors: Atherton Peter R.
Published: November 2005

To introduce rendered surface display technology into the production design environment, many CAD operations envision a single color video display device for
download
processing of selected model pictures. Creation of a single image from a typical industrial CAD model involving a large number of higher order curved surfaces will normally require a minimum of several minutes' delay for data acquisition and visible surface computation. This paper describes a method that extends the visible surface operation to give the designer an interactive tool with which he can more effectively comprehend model composition. Instead of defining data for a single image, an intermediate three-dimensional structured file is created. A
tailored
display program manipulates the structured data file allowing a user to interactively create surface rendered images. Program capabilities include:

• Section and cutaway viewing

• Selected surface color, transparency, or translucency

• Shadows projected from desired light-source locations

Changing or combining any of these facilities requires only seconds for a new image to be created.
A reflectance model for computer graphics
Authors: Cook Robert L. , Torrance Kenneth E.
Published: November 2005

This paper presents a new reflectance model for rendering computer synthesized images. The model accounts for the relative brightness of different materials and light sources in the same scene. It describes the directional distribution of the reflected light and a color shift that occurs as the reflectance changes with incidence angle. The paper presents a method for obtaining the spectral energy distribution of the light reflected from an object made of a specific real material and discusses a procedure for accurately reproducing the color associated with the spectral energy distribution. The model is applied to the simulation of a metal and a plastic.
Rapid, stable fluid dynamics for computer graphics
Authors: Kass Michael , Miller Gavin
Published: November 2005

We present a new method for animating water based on a simple, rapid and stable solution of a set of partial differential equations resulting from an approximation to the shallow water equations. The approximation gives rise to a version of the wave equation on a height-field where the wave velocity is proportional to the square root of the depth of the water. The resulting wave equation is then solved with an alternating-direction implicit method on a uniform finite-difference grid. The computational work required for an iteration consists mainly of solving a simple tridiagonal linear system for each row and column of the height field. A single iteration per frame suffices in most cases for convincing animation.Like previous computer-graphics models of wave motion, the new method can generate the effects of wave refraction with depth. Unlike previous models, it also handles wave reflections, net transport of water and boundary conditions with changing topology. As a consequence, the model is suitable for animating phenomena such as flowing rivers, raindrops hitting surfaces and waves in a fish tank as well as the classic phenomenon of waves lapping on a beach. The height-field representation prevents it from easily simulating phenomena such as breaking waves, except perhaps in combination with particle-based fluid models. The water is rendered using a form of caustic shading which simulates the refraction of illuminating rays at the water surface. A wetness map is also used to compute the wetting and drying of sand as the water passes over it.
Antialiasing of interlaced video animation
Authors: Amanatides John , Mitchell Don P.
Published: November 2005

The production of computer-generated video presents a number of difficulties not encountered with motion pictures. Interlaced scanning and the color subcarrier of NTSC video are responsible for special problems such as interline flicker, and chroma aliasing. As in motion pictures, temporal aliasing is also an issue. A renderer can sample and filter a moving image in an arbitrary manner and is not constrained to simply imitate the behavior of a television camera. This paper explores several different spatiotemporal antialiasing filters and how they affect the quality of video animation.
Merging BSP trees yields polyhedral set operations
Authors: Naylor Bruce , Amanatides John , Thibault William
Published: November 2005

BSP trees have been shown to provide an effective representation of polyhedra through the use of spatial subdivision, and are an alternative to the topologically based b-reps. While bsp tree algorithms are known for a number of important operations, such as rendering, no previous work on bsp trees has provided the capability of performing boolean set operations between two objects represented by bsp trees, i.e. there has been no closed boolean algebra when using bsp trees. This paper presents the algorithms required to perform such operations. In doing so, a distinction is made between the semantics of polyhedra and the more fundamental mechanism of spatial partitioning. Given a partitioning of a space, a particular semantics is induced on the space by associating attributes required by the desired semantics with the cells of the partitioning. So, for example, polyhedra are obtained simply by associating a boolean attribute with each cell. Set operations on polyhedra are then constructed on top of the operation of merging spatial partitionings. We present then the algorithm for merging two bsp trees independent of any attributes/semantics, and then follow this by the additional algorithmic considerations needed to provide set operations on polyhedra. The result is a simple and numerically robust algorithm for set operations.
Incremental radiosity: an extension of progressive radiosity to an interactive image synthesis system
Authors: Chen Shenchang Eric
Published: November 2005

Traditional radiosity methods can compute the illumination for a scene independent of the view position. However, if any part of the scene geometry is changed, the radiosity process will need to be repeated from scratch. Since the radiosity methods are generally expensive computationally, the traditional methods do not lend themselves to interactive uses where the geometry is constantly changing. This paper presents a new radiosity algorithm to incrementally render scenes with changing geometry and surface attributes. In other words, the question to be asked is "
What is the minimum recomputation I need to do if I turn off a light source, change the color of a surface, add or move an object?
" Because a modeling change generally exhibits some coherence and affects only parts of an image, the proposed method may drastically reduce the rendering time and therefore allow interactive manipulation. In addition, since the method is conducted incrementally and view-independently, the rendering process can start before the modeling process is completed. The traditional paradigm of
modeling-then-rendering
is changed to
rendering-while-modeling
. This approach not only gives the user better visual feedback but also effectively utilizes CPU time otherwise wasted in the modeling process.
Rapid controlled movement through a virtual 3D workspace
Authors: Mackinlay Jock D. , Card Stuart K. , Robertson George G.
Published: November 2005

Computer graphics hardware supporting real-time interactive 3D animation has the potential to support effective user interfaces by enabling virtual 3D workspaces. However, this potential requires development of viewpoint movement techniques that support rapid and controlled movement through workspaces. Rapid movement through large distances avoids wasted work time; controlled movement near target objects allows the user to examine and interact with objects in the workspace. Current techniques for viewpoint movement typically use high velocities to cover distances rapidly, but high velocities are hard to control near objects. This paper describes a new technique for targeted viewpoint movement that solves this problem. The key idea is to have the user indicate a point of interest (target) on a 3D object and use the distance to this target to move the viewpoint logarithmically, by moving the same relative percentage of distance to the target on every animation cycle. the result is rapid motion over distances that slows as the viewpoint approaches the target object. The technique can be used with 2D and multidimensional input devices. We also extend the technique to move objects in the workspace.
Strength guided motion
Authors: Lee Philip , Wei Susanna , Zhao Jianmin , Badler Norman I.
Published: November 2005

A methodology and algorithm are presented that generate motions imitating the way humans complete a lifting task under various loading conditions. The path taken depends on "natural" parameters: the figure geometry, the given load, the final destination, and, especially, thestrength modelof the agent. Additional user controllable parameters of the motion are thecomfortof the action and theperceived exertionof the agent. The algorithm uses this information to incrementally compute a motion path of the end-effector moving the load. It is therefore instantaneously adaptable to changing force, loading, and strength conditions. Various strategies are used to model human behavior (such as reducing moment, pull back, add additional joints, and jerk) that compute the driving torques as the situation changes. The strength model dictates acceptable kinematic postures. The resulting algorithm offers torque control without the tedious user expression of driving forces under a dynamics model. The algorithm runs in near-realtime and offers an agent-dependent toolkit for fast path prediction. Examples are presented for various lifting tasks, including one-and two-handed lifts, and raising the body from a seated posture.
Accurate rendering technique based on colorimetric conception
Authors: Takagi Atsushi , Takaoka Hitoshi , Oshima Tetsuya , Ogata Yoshinori
Published: November 2005

We have developed a rendering technique to generate realistic images meeting designers' requirements by strictly analyzing various physical phenomena relevant to the appearance of actual objects.We have numerically compared the results of the calculations using this technique with colorimetry values. As a result, both values were virtually equal, so we have been able to confirm the effectiveness of the established technique.Application of this technique to car design, which has not been realized to a large extent because of severe requests for realism, will make it possible to evaluate styles and colors on a graphics display before making a clay model.
Light-water interaction using backward beam tracing
Authors: Watt Mark
Published: November 2005

A new two pass approach is presented based on a variation of backward ray tracing backward beam tracing. Advantages include its capability of rendering complex, hitherto unattainable, specular to diffuse phenomenon and its easy insertion into standard renderers. The algorithm is applied to aspects of the interaction of light with water. Within this context a variety of first generation effects, including shadowing and light scattering, are both rendered and animated. Results taken from the treatment of caustics within classical optics are included as they provide valuable insights into the precise nature of specular to diffuse transfer.
A lighting model aiming at drive simulators
Authors: Nakamae Eihachiro , Kaneda Kazufumi , Okamoto Takashi , Nishita Tomoyuki
Published: November 2005

Many techniques for rendering natural objects such as the sea, terrains, and trees have been developed; they are indispensable for flight simulators. In this paper, techniques for rendering road surfaces under various conditions are discussed. Rendering road surfaces is quite useful for the evaluation of driving safety, and it will play an important part in the development of drive simulators. Light sources with high intensity often disturb drivers especially under wet road surface conditions.This paper proposes two models, a reflection model for road surfaces taking into account weather conditions, and a model on streaks of light taking into account both refraction and diffraction of light. Some examples demonstrate the possibility of applications for drive simulators in the future.
Particle animation and rendering using data parallel computation
Authors: Sims Karl
Published: November 2005

Techniques are presented that are used to animate and render particle systems with the Connection Machine CM-2, a data parallel supercomputer. A particle behavior language provides an animator with levels of control from kinematic spline motions to physically based simulations. A parallel particle rendering system allows particles of different shapes, sizes, colors and transparencies to be rendered with antialiasing, hidden surfaces, and motion-blur. One virtual processor is assigned to each primitive data element: one to each particle, and during the rendering process, one to each pixel-sized particle fragment, and to each pixel. These tools are used to model dynamic phenomena such as wind, snow, water, and fire.
The challenge of computer graphics in Continental Western Europe
Authors: Guedj R. A.
Published: November 2005

Computer graphics applications, software, and hardware research, are examined and evaluated in Continental Western Europe. Growth has been slow. The reasons are the high cost of hardware and the complexity of the required software. The past reveals a rather dim picture. Mechanical engineering applications have shown some promising success. Electrical engineering applications have been effective mainly for PCB and IC mask layout only. Interactive graphic software has not yet effectively found its way outside Fortran. APL-G seems an interesting graphic extension of the language APL. Promising trends appear to be on the horizon. They are related to hardware and software trade-offs, as, for example, in the TALENT System.The need for computer graphics still exists. The hardware and software tradeoffs will receive more attention. Success in computer graphics will depend upon advances in computer systems design, especially programming languages and systems. Computer graphics has yet to come of age.
Intelligent satellites for interactive graphics
Authors: Van Dam A. , Stabler G. M. , Harrington R. J.
Published: November 2005

The spectrum of remote user stations with local processing ability, ranging from simple "smart" terminals to nearly self-sufficient intelligent systems called satellites, is considered. The emphasis is on the latter category, drawing on the authors' research on intelligent satellites for interactive graphics. The necessity of meeting a "critical intelligence threshold" criterion for the satellite is stressed, and some difficult problems and potential solutions in the division of labor between mainframe and satellite are briefly examined. It is hoped that many of the problems and solutions in satellite graphics apply to other areas such as network or satellite process control, experiment control, and signal processing.
Computer-encouraged serendipity in pure mathematics
Authors: Strauss C. M.
Published: November 2005

Computer applications to research in pure mathematics during the past several years have concentrated on using the data processing and logical capabilities of computers to carry out exhaustive and exhausting combinatorial or logical manipulations. Computers can also be used to suggest entirely new theorems and results, but this sort of application has not yet been particularly widely investigated.The addition of an interactive graphics terminal to even a small to medium-sized computer enables one to construct "n-dimensional blackboard." On this device a mathematician can display and manipulate two-dimensional projections of n-dimensional geometrical constructs with much greater speed and accuracy than he can bring to his usual blackboard sketches. This sort of facility can be particularly helpful to the type of mathematician who thinks geometrically, and who relies a great deal on geometrical visualizations to suggest new theorems and proofs. Using control dials, joysticks, and other analog input devices, a mathematician can get immediate portrayal of the geometric effect of continuously varying parameters. He also has finger-tip control over the current values of these parameters, encouraging the development of a visceral feeling for the effect of these parameter variations.Early experience with such an "n-dimensional blackboard," implemented in a prototype version on the microprogrammed mini-computer BUGS system at Brown University, is extremely promising. This BUGS blackboard, used in the area of singularities of algebraic curves in complex two-space, has suggested several new theorems and areas for further investigation.A description is given of the facilities of the BUGS blackboard. Also, the observed interaction between the physical facilities available on the BUGS system is mentioned, as well as the sorts of mathematical results that the use of these facilities in the BUGS blackboard seems to encourage.
Computer graphics and art
Authors: Csuri C.
Published: November 2005

A survey of basic ideas and approaches to computer art is given. Statements are presented by several computer artists as well as illustrations of their work. Comments are made about the relationship of computer graphics to art including a brief historical sketch of developments in this area. A conceptual framework is presented for interactive art objects as an art form. Suggestions are made about the future of computer art and the importance of a relationship between art and science.
MINI-EXPLOR
Authors: Knowlton Ken
Published: November 2005

The EXPLOR language, which generates designs from Explicit 2-D Patterns, Local Operations, and Randomness, has been useful not only in providing the computer novice with graphic output; it has also been a vehicle for introducing many other basic computational notions: algorithms, nested loops, sorting, heuristics and search, cellular automata, Monte Carlo calculations, finite state machines.This paper described a simplified version of the system, coded in only 430 lines of FORTRAN, which can run on most 16-bit word (or larger) machines having 8K to 16K of core storage. Such an implementation, by means of line printer or teletype output, can now produce almost as rich a variety of results as previously-reported much larger versions.
Reversed apparent movement and erratic motion with many refreshes per update
Authors: Lipscomb James S.
Published: November 2005

Image quality in refresh computer graphics is degraded when the image is in motion but not being moved across the screen once with each refresh. Multiple images, reversed apparent movement, jerky motion, and erratic motion can be the result.These problems were faced during the construction of GRIP-75, a vector graphics molecular modeling system.
"Methodology in computer graphics" re-examined
Authors: Rosenthal David S. H.
Published: November 2005

The design of proposed graphics standards is based on a methodology developed some years ago. Technical reviews of these proposals have illuminated some aspects of this methodology, and on this basis alternatives can be explored. One alternative methodology is proposed, and its advantages explored by means of a simple graphics system.
The requirement for process structured graphics systems
Authors: Arnold David
Published: November 2005

The proposed standards for computer graphics are based on models of hardware configurations which were appropriate ten years ago. Today the applicability of these models must be questioned and the essential characteristics of future systems predicted, in order to allow suitable systems to be designed now for use by the future user community. The standards proposals do not seek to impose an implementation structure on future packages, merely to define the inputs and outputs from a 'black box'. However these definitions must be examined to expose any areas in which they exclude the possibility of some desirable implementation techniques. In particular the desirability of process oriented graphics systems should be established and the current proposals examined for pitfalls to adopting this type of implementation policy.
Construction and display of three-dimensional polygonal-histograms
Authors: Hilbert Ross
Published: November 2005

A new algorithm for displaying a set of prisms constructed on a 2-D tiling composed of simple polygons is presented. Throughout this paper let a prism be defined as a polyhedron with two congruent and parallel faces that are joined by a set of rectangles.The 2-D tiling, given as ordered pairs (x,y) representing the vertices of the polygons, is located on the base plane z = 0. A positive value is associated with each polygon, establishing the top of the prism constructed upon it. The resulting scene is displayed with hidden lines removed and shading. Compared to the existing algorithm for this problem, the algorithm presented here is less complicated, more versatile, and equally fast. If the 2-D tiling is to be provided by the system and accessed by the user community with varying viewpoints and/or heights, the algorithm presented here is faster than previously published solutions.