Abstract: The techniques developed by M. M. Brown and R. Sedgewick (1985) in using the Balsa algorithm-animation system are reviewed. Techniques that focus on color and sound, areas just opening up in workstation-based interactive algorithm-animation systems, are described. Color is used for encoding the state of data structures, highlighting activity, trying multiple views together, emphasizing patterns, and making an algorithm's history visible in a single static image. Sound is used for reinforcing visuals, conveying patterns, replacing visuals, and signaling exceptional conditions. The techniques are based on work done with the Zeus algorithm-animation system. Six screen dumps from six different algorithm animations that are representative of the was Zeus was used are presented. >

Abstract: The VolVis system has been developed to satisfy the diverse requirements of the volume visualization community by comfortably housing numerous visualization algorithms and methods within a consistent and well organized framework. The VolVis system is supported by a generalized abstract model which provides for both geometric and volumetric constructs. VolVis contains several rendering algorithms that span the speed versus accuracy continuum. A fast volume rendering algorithm has been developed, which is capable of exploiting existing graphics hardware without placing any viewing restrictions or compromising accuracy. In addition, VolVis includes a volumetric navigation facility, key-frame animation generator, quantitative analysis tools, and a generalized protocol for communicating with 3D input devices. >

Abstract: In this dissertation, parametric L-systems are presented as the foundation of a computer graphics tool for simulating and visualizing the development of plants. L-systems were introduced in 1968 by Aristid Lindenmayer as a mathematical model of multicellular organisms. They employ a parallel string-rewriting mechanism to describe the development of branching structures. The resulting strings can be interpreted geometrically and visualized using computer graphics techniques to create both realistic and schematic images of the modelled structures. The formalism can be applied for a variety of scientific, educational, and commercial purposes. Parametric L-systems extend the original concept of L-systems by associating numerical parameters with the symbols representing plant components. This allows easy quantification of geometric attributes of a model, and provides a simple means for the expression of continuous processes, such as diffusion of hormones and the resulting distribution of concentrations. Formal definitions are proposed for context-free and context-sensitive parametric L-systems with either deterministic or stochastic application of production rules. The practical value of parametric L-systems is demonstrated in this dissertation by examples that include models of plants ranging from algae to trees. Model development is controlled by lineage mechanisms, with information passed from parent to child module. This mechanism is combined in some models with endogenous interaction, where information flows through a growing structure. Selected models are suitable for simulating time-lapse photography through computer animation. Extensions to the formalism of parametric L-systems incorporate useful features of other programming languages and provide techniques for creating hierarchical models.

Abstract: The geographic information revolution is rapidly increasing the availability of data that are referenced both by space and by time coordinates. This creates new opportunities for analysis, but also causes enormous problems as analytical tools able to depict, detect, or measure patterns in space-time data are poorly developed. The question arises as to whether or not a greater emphasis on the dynamics of spatial patterns may assist the analysis task. This is investigated by creating a series of VHS-format computer animations using an inexpensive microcomputer (an Acorn Archimedes). The technology is demonstrated by the analysis of leukaemia data for northern England, telephone line faults, and crime incidence in Tyne and Wear. The results provide an entirely new perspective on the nature of spatial patterns thought to exist and demonstrates the potential of hypermedia technology as a platform for new and novel approaches to spatial analysis.

Abstract: This multimedia paper elaborates on the comprehensive physicallybased light reflection model introduced by He et al. [ 11.To explain the model more fully, the paper gives an overview of the light reflection process at a surfiace, and employs an interactive graphical tool to demonstrate the reflection model’s directional behavior. To make the model more practical, the paper describes an accurate approximation of the reflection model. based on a spline surface, that is much faster to compute. The paper concludes with two animated sequences, which demonstrate some features of light reflection that are accounted for by the model. The full paper demonstrates the potential of interactive multimedia. It is written using MediaVlew [2], a system for authoring documents that include graphics, sound, video, and computer animation, CR

Abstract: Describes AACE, a methodology for educational algorithm animation that the author developed while building an integrated hypermedia algorithm animation environment extending a fundamental algorithms textbook. After presenting the general structure of AACE, he discusses questions of the ideal user interface for algorithm animations. He compares his approach to the development of algorithm animation that he calls 'structure-based' with the more conventional 'unified view'-based approach. >

Abstract: An ideal self-study text, this book presents a lucid and accessible guide to modern techniques for 3-dimensional computer animation. Features includes a wealth of examples and illustrations (including a flick-book sequence and 8 pages of colour plates extensive reference section provides a complete guide to the literature on computer animatio presents the latest algorithms in a language-independent way

Abstract: ion of information into visual form plays a key role in the development of algorithm animations. The authors present a classification for abstraction as applied to algorithm animation. The classification emphasizes the expressive power of the abstraction ranging from simple direct presentation of the program's state to complex animations intended to explain the behavior of the program. They illustrate their classification by presenting several visualizations of a shortest path algorithm. >

Abstract: Publisher Summary Depth of field is defined as the area enveloping the focal plane in an optical lens system within which objects retain a definitive focal quality. Photographers and cinematographers have long used that aspect of the camera's lens and aperture to direct the viewer's attention to a particular part of the image away from the areas outside the field of interest. Because of that, it can be advantageous for a computer animation system to include depth-of-field effects in its repertoire. This chapter describes a 2 1/2 -D depth-of-field algorithm for simulating change-of-focus in computer-generated animation. The 2 1/2 -D depth-of-field algorithm is virtually independent of any hidden-surface removal technique. When gradually changing filters are applied to successive frames of an animation sequence, the effect is to pull the viewer's attention from one depth plane of the scene to another. The 2 1/2 -D depth-of-field algorithm can be considered a compromise between two methods: (1) when shading is integrated with depth of field and (2) when surface visibility is combined with depth of field in a restricted way.

Abstract: The authors describe a simulation environment which can be of utility in the design, development, and operation of sensor-driven robotic systems. This environment incorporates the ability to simulate sensory inputs and their effects on the planning and control functions. A detailed design of the simulator is presented. The simulator is integrated within an entire robotic system, and is utilized for automatic robot programming. Alternatively, the simulated system operation flow can be controlled through either a teach mode or a program mode. Five sensing modalities can be simulated: proximity, point laser range, ultrasonic range, laser range depth imagery, and edge-based intensity imagery. The simulation and animation of a particular robot is described. The unique features of the simulator are that it simulates and utilizes sensory information feedback, it integrates planning and simulation, and it makes the switching between real and simulation mode in the robotic system transparent to the user. >

Abstract: Managers of hardwood processing facilities need timely information on which to base important decisions such as when to add costly equipment or how to improve profitability subject to time-varying demands. The overall purpose of this paper is to introduce a method that can effectively provide such timely information. A simulation/animation modeling procedure is described for hardwood products manufacturing systems. Object-oriented simulation modeling techniques are used to assist in identifying and solving problems.

Abstract: Recently, program visualization systems have received much attention as learning tools and as software understanding aids. How to evaluate these systems, however, is an open and unexplored area. In order to determine what factors may be important, we conducted an exploratory study using XTango, an algorithm animation system. First, we asked professors to complete surveys intended to solicit information regarding current practices in the teaching of algorithms. Next, we observed two groups of students: one group received a handout and viewed an animation of the Shellsort algorithm, the other received the same handout and listened to a lecture featuring drawings on the blackboard. The students were queried on their understanding of the sort and their impressions of the animation system. Comments indicated a high perceived value for the system, with most students favoring its use as a teaching tool. It was clear from students' responses that an algorithm animation system can be used more effectively as a supplement in the classroom environment than as a substitute for the teacher. The results of this study identified changes to the animation system that will help integrate it into the classroom environment, and provided several important factors to consider in future empirical studies.

Abstract: I: Physics-based Animation.- The Control of Hovering Flight for Computer Animation.- Inverse Problems in Computer Graphics.- NPSNET: Physically-based Modeling Enhancements to An Object File Format.- A New Method for Approximative Interactive Dynamics.- II: Human animation.- Extraction of 3D Shapes from the Moving Human Face Using Lighting Switch Photometry.- An Interactive Tool for the Design of Human Free-Walking Trajectories.- Achilles - A System for Visualizing Non Standard Human Gait.- FAERIE: A CAD/CAM Tool for Voluntary Movement and Ergonomic Simulation.- Hand Motion Coding System for Algorithm Recognition and Generation.- III: Path Planning and Motion Control.- Computer Animation of Robot Motion with Collision Free Path Planning.- Path Planning and its Application to Human Animation System.- Automating Virtual Camera Control for Computer Animation.- IV: Geometric Models.- Algorithmic Animation of Constructing Surfaces from Cells.- Controlling the Architectural Geometry of a plant's growth - Application to the Begonia Genus.- Intersection and Minimal Distance of 3-D Object.- V: Languages and Systems.- Hierarchy, Labels and Motion Description.- A Language for Animating Scene Descriptions.- Risk and QFD Guided Prototyping of Graphical Animation Software.- A Video Editor for Teaching and Research in Computer Animation.- Author index.- Keyword index.

Abstract: In this paper, we present a general, systematic and consistent treatment of time and events for computer animation. We first formalize the concepts of events and create a time primitive called an event unit. We then present a succession of organization schemes to compose event units for generating complex motion sequences. We present a directed graph representation for the organization of time and events that suggests the form of an event-based time programming language. Details of implementation of a general event simulation system are given. Our approach provides a clean partitioning for the problem of motion design, a hierarchical scheme to compose motion behaviors from time primitives and a programming model for organizing animation. Traditional methods of kinematic controls and key frame interpolation are special cases of our general scheme. In addition, our treatment of events can be combined with kinematics, dynamics or constraint-based systems to generate powerful motion modeling systems.

Abstract: The grand piano action is modeled as a set of four rigid bodies using Kane’s method. Computerized symbol manipulation is utilized to streamline the formulation of the equations of motion so that several models can be considered, each of increasing detail. Various methods for checking the dynamical model thus derived are explored. A computer animation driven by simulation of the equations of motion is compared to a high-speed video recording of the piano action moving under a known force at the key. For quantitative evaluation, the velocities and angular velocities of each of the bodies are extracted from the video recording by means of digitization techniques. The aspects of the model of particular interest for emulation by a controlled system, namely, the mechanical impedance at the key and the velocity with which the hammer strikes the string, can be studied in the equations of motion and compared to empirical data.

Abstract: The analysis of human motion can be advanced by analyzing motion, not only numerically, but also graphically. We present a system for the three-dimensional graphical analysis of human motion. The system involves the integrated operation of an image acquisition unit, a robot arm for 3-D target presentation, an image reconstruction unit, graphic analysis, and animation software. A five degree of freedom robot arm is used to present single targets or target trajectories for subjects to track. All the locations are software generated based on mathematical formulation of the desired sectoring of space. Two optoelectronic cameras are used to directly sense the positions of the diodes. Three-dimensional trajectories of each point are computed from the two sets of 2-D images. The 3-D trajectories of the robot and of the subject are reconstructed and displayed on a Silicon Graphics Iris Workstation. A variety of programs display kinematic features of the hand and joint trajectories synchronized with reconstructed images of the three-dimensional trajectory paths of individual limb segments. The user has real-time interactive control over the viewing angle, size, and screen position of the limb trajectories. Image representing all 3-D target and finger positions and scatterplots of target and finger distance, azimuth, and elevation from the shoulder can also be presented. Finally, software was developed to display the reconstructed motion of the arm by representing the various segments of the arm as surfaced cylinders. Effects of light source, shading and shadowing are used for calculations of brightness over the surface of the various cylinders. The end points of each cylinder are determined by the 3-D locations of infrared diodes which were attached to the subject's limb segments. The arm is animated to reproduce the velocity patterns inherent in the digital trajectory records. There are various interactive options for viewing the moving image of the arm together with representations of the trajectories of the individual joints.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: The animation display controller to interpret a scenario description managed by a scenario description manager. According to the interpretation, it reads an animation display unit from an animation display unit manager and displays time series data of animation display units through a plurality of windows opened on a display. As a result, related animation images are displayed on the display in the multiple window format. The animation display controller also performs a backward process of animation display units included in transit-in-time-series at a user's request according to managing data input unit, a user can edit an animation display unit managed by the animation display unit manager and a scenario description managed by the scenario description manager. Specifically, the scenario description editor graphically edits scenario descriptions.

Abstract: Psychophysical experiments involving moving stimuli require the rapid presentation of animated sequences of images. Although the Macintosh computer is widely used as a color graphics computer in research laboratories, its animation capabilities are generally ignored because of the speed limitations of drawing to the screen. New off-screen color graphics structures help to avoid the speed limitations so that real-time color or gray-scale visual motion stimuli may be generated. Precomputed animation frames are stored in off-screen memory and then rapidly transferred to the screen sequentially. The off-screen graphics structures may also be saved to disk in “Picture” form as “resources” for later retrieval and playback, allowing the experimenter to build in advance a collection of moving stimuli to use in future experiments. Code examples in the C programming language are provided, and the relative strengths and weaknesses of Macin-tosh color-frame animation for psychophysical experimentation are discussed.

Abstract: The potential of computer animation has been realized in many different disciplines. Animation is also a powerful visualization tool for cartography; however, it has been neglected until recently. This paper portrays the need for animation in cartography in the light of the new approaches and methods in the sciences as well as in society. It discusses two main reasons for the lack of animation in cartography: the fixation on the printed map and the absence of a comprehensive approach to cartographic animation. Finally, a variety of issues for further research are proposed.

Abstract: PURPOSE: To provide an animation image recording medium and an animation image recorder and a reproducing device which can generate images for fast forward reproducing considering image contents. CONSTITUTION: In the case of recording animation image, information 2 in the animation image recording medium 1, the scene change of the animation image is automatically detected and the length of a scene and the change degree of the image in the same scene are automatically stored in an animation image managing information storage part 3 together with the address of the animation image changing the scene so that managing information can be automatically imparted to all the parts to change the image contents in the animation images without any manual work. Then, the address of the animation image to be extracted is decided basing on the time length of the summarized animation image requested from a user, the length of the scene in the animation image managing information provided in the animation image recording medium 1 and the change degree of images in respective scenes, and the images for fast forward reproducing can be generated corresponding to the contents of animation images. COPYRIGHT: (C)1994,JPO&Japio

Abstract: We propose a new method for the automatic printing of holographic three-dimensional (3-D) animation viewed under white-light illumination. One can display the animated 3-D image near the hologram plane by vertically scrolling the hologram. Since the hologram consists of small elemental holograms that are individually recorded at multiple exposures, the image size and the playback length are not restricted by the size of the recording optical system. A 3-D animation of 25 frames is experimentally recorded. Clear 3-D images can be observed by pulsed-light illumination.

Abstract: Motion control and surface modelling remain the two major challenges in the creation of articulated figures for computer animation. This thesis addresses motion control with an interactive figure manipulation tool encorporating dynamic analysis with kinematic constraints, and surface modelling with a new approach to surface representation using tensor-product splines. Kinematic control in computer animation is time-consuming, because the manipulation of an articulated figure requires the positioning of large number of interdependent degrees-of-freedom. Dynamic analysis (simulation through the Newtonian equations of motion) has been proposed as an aid in this process, but algorithms incorporating kinematic constraints are too slow to be used in an interactive system. Recursive dynamic formulations run at interactive rates on current hardware but do not directly accommodate kinematic constraints. Manikin is an interactive animation system unifying both kinematic procedures and dynamic analysis for motion control in the positioning of articulated figures for key-frame animation. A novel method of incorporating kinematic constraints into a recursive dynamic formulation is presented. Modelling the skin of an articulated figure requires a smoothly flowing surface covering the limbs and deforming realistically around the joints as the underlying skeleton changes position. With polygonal models, additional polygons are easily created where they are needed, but a prohibitively large number of data points are required to represent a smooth surface. Tensor product spline surfaces are smooth; however, patches cannot be added locally but must be created by splitting an entire row or column of patches. This non-local refinement adds significantly to the number of patches required to represent a surface and makes manipulation, especially in the design and animation of computer characters, difficult. A hierarchical free-form surface is a new, general, space efficient approach to the representation of tensor-product spline surfaces that offers greater editing flexibility than is found with traditional representations. This representation is a data structuring technique allowing local refinement of a tensor-product spline surface, so that the number of patches in a given region can be increased without affecting the rest of the surface. The hierarchical form is applicable to any spline with a refinement procedure and locally supported basis functions. Applications include spline curves and volumes as well as surfaces, and a method using the hierarchical form in fitting tensor-product surfaces to gridded data is also presented. The hierarchical form, coupled with a reference plus offset representation of the hierarchy, allows surface manipulation independent of refinement and allows broad scale changes in surface shape that maintains fine scale surface details. These properties greatly ease the task of creating a realistic animated figure with a single tensor-product spline surface and are useful in free-form surface design in general.

Abstract: A menu-driven interactive graphics software package has been developed for use as an instructional aid for the electric machines course in the electrical engineering curriculum. The main purpose of this tool is to give the students a clearer understanding of the basics of the operation of rotating electric machines. The animation program was developed for displaying live and rotating diagrams depicting different modes of operation of synchronous generators. Different parts are identified with different colors. The interaction of the magnetic poles on the stator and on the rotor, and the relative spatial positions and time variations of the magnetic and electric quantities are demonstrated through moving images. The software features are described. >

Abstract: A simulator has been built to teach doctors the skill of handling a flexible endoscope for gastrointestinal investigations. Trainees use a dummy endoscope in which the control actions are transduced into voltages and sensed by the computer. The simulator computes the position and viewing direction of the endoscope within an internal model of the human colon. Then a renderer draws the view, reproducing as far as possible what would be seen during a real colonoscopy. Since the system must generate at least ten frames per second for realistic animation, standard rendering techniques, such as ray tracing, could not be used. Consequently a new method was devised, based on identifying coherent regions along each scan line which can be rendered by table lookup. The method allows shaded Lambertian surfaces to be drawn at a frame rate of 15 per second, using modest computing resources. Although several approximations were required in the analysis, the computer images of the internal surfaces of the human colon present a high degree of visual realism.

Abstract: Providing an overview of computer animation, from basic principles to more esoteric developments such as virtual reality and parametric modelling, this book is intentionally broad in scope and illuminated by many diagrams and illustrations. This book communicates teh excitement shared by those who work in this field to those who seek a comprehensive introduction.

Abstract: The authors propose the use of interactive animation techniques as a support to reverse engineering processes oriented to the synthesis of semantic abstractions. Starting from data flow diagrams, a formal model, called dynamic data flow diagrams (DDFDs), has been defined, which can be used for the production of executable models of a software system. A strategy for the DDFD interactive animation is also put forward. Finally, the authors describe a prototype tool for (i) the production of the DDFD which models an ADA system starting from the analysis of the code and (ii) the interactive animation of such a model according to the proposed strategy. >

Abstract: L systems have been used as a tool for computer graphics and computer animation. Occasionally their limitations in this context have been criticized. In order to evaluate the potential and limitations of L systems in this context rigorously, however, one requires a sufficiently general formal notion of graphical interpretation of L systems.