Abstract: There are many possible ways of identifying the posture of a human character from a set of known positions. These methods differ in subtle but important ways. We propose an alternative method to the jacobian-based Inverse Kinematics, one which allows for simple calibration, allows for sensors slippage, and can take advantage of knowledge of the type of motion being performed. This approach gives real-time conversion of magnetic sensors measurements into human anatomical rotations. Our converter is used in a wide range of applications from real time applications to animation design. It provides a useful complement to the traditional keyframe editing software.

Abstract: This paper reports a laboratory experiment that investigated the relative effects of images, transitions, and interactivity styles used in animated interfaces in two decision making domains. Interfaces used either realistic or abstract images, smooth or abrupt transitions, and parallel or sequential interactivity. Results suggest that decision making performance is influenced by the task domain, the user experience, the image, transition, and interactivity styles used in animated interfaces. Subjects performed better with animated interfaces based on realistic rather than abstract images. Subjects were more accurate with smooth rather than abrupt animation. Subjects were more accurate and enjoyed more the animation with parallel rather than sequential interactivity. Implications on the design of animated interfaces for decision making are provided. To account for appropriateness and interactivity, animation in HCI can be defined as: a series of varying images presented dynamically according to user actions in ways that help the user to perceive a continuous change over time and develop a more appropriate mental model of the task [7]. A task is generally considered a meaningful unit of work performance, and interactivity is usually defined by the visible or motor actions the user performs on the interface. This paper summarizes previous empirical research on animation and reports a laboratory study conducted to evaluate the decision making effectiveness of different types of images, transitions, and interactivity styles used in animated interfaces. The paper concludes with implications and recommendations concerning the design of animated interfaces for supporting decision making.

Abstract: Using rational motions it is possible to apply many fundamental B-spline techniques to the design of motions. The present paper summarizes the basic theory of rational motions and introduces a linear control structure for piecewise rational motions suitable for geometry processing. Moreover it provides algorithms for the calculation of the surface which is swept out by a moving polyhedron and examines interpolation techniques. The methods presented in this paper can be applied to various problems in computer animation as well as in robotics.

Abstract: Background.- Functional Anatomy of an Artificial Fish.- Biomechanical Fish Model and Locomotion.- Modeling the Form and Appearance of Fishes.- Perception Modeling.- The Behavior System.- Modeling the Marine Environment.- The Graphical User Interface.- Animation Results.- Conclusion and Future Work.- Epilogue.

Abstract: Mass/Spring networks are commonly used to produce simulations of deformable bodies for computer animation. However, such an approach can produce inaccurate results if too coarse a discretisation is employed, and so many animators use excessively large (and slow) networks. In order to remove the ‘guesswork’ from such an approach this paper presents a mechanism for adaptively refining portions of such systems to a required accuracy, thereby producing more pleasing results at a reduced computational cost. Following a discussion of the use of such an approach in simulating a deformable sheet, we present several characteristic examples to demonstrate its suitability.

Abstract: Virtual Actors now play an important role in computer-generated films, Virtual Environments, Telecooperative work, and multimedia. In order to make these actors realistic, it is essential to represent their body shape during the motion. In this paper we present different methods for representing realistic deformations for virtual humans with various characteristics: sex, age, height, weight. Our methods based on a combination of metaballs and splines could be applied to frame-by-frame computer generated-films and Virtual Environments. Several examples are presented: autonomous actors, animation based on flock of birds, networked Virtual Environments.

Abstract: From the Publisher: Grounded in the basics of traditional cel animation, Digital Character Animation provides the essential information needed to create convincing computer-generated characters in 2D and 3D. Applying conventional character animation techniques such as walk cycles and lip sync to computer animation is explained, along with tips for giving your characters the illusion of life. This step-by-step guide is not software specific: you get selected examples shown in various programs, along with a discussion of tools and techniques common to all major animation programs. Digital Character Animation ensures that your skills will be applicable no matter what the job!

Abstract: Computer animation has been considered for many years as a new media for advertising and special effects in films. More recently, the fast development of powerful workstations has led to new areas like multimedia, interactive games and virtual reality. For these areas, interactive animation has become a key issue. Tackling the challenge of creating human motion through a computer, this book examines specific techniques such as cloth, hair and facial animation, and the co-ordination of animated objects.

Abstract: The paper describes CAT, a Web-based algorithm animation system. CAT augments the expressive power of Web pages for publishing passive multimedia information with a full-fledged interactive algorithm animation system. It improves on previous Web-based algorithm animations by providing a framework that makes it easy to construct new animations, including those that involve multiple views. Because views of the same running algorithm may reside on different machines, CAT is particularly well-suited for electronic classrooms. This strategy is an improvement over the electronic classroom systems the authors are aware of which simply display the same X window on multiple machines. They believe their framework generalizes to electronic textbooks in arbitrary domains.

Abstract: The motion of a human platform diver was simulated using a dynamic model and a control system. The dynamic model has 32 actuated degrees of freedom and dynamic parameters within the range of those reported in the literature for humans. The control system uses algorithms for balance, jumping, and twisting to initiate the dive, sequences of desired values for proportional-derivative servos to perform the aerial portion of the dive, and a state machine to sequence the actions throughout the dive. The motion of the simulated diver closely resembles video footage of dives performed by human athletes. The control and simulation techniques presented in this paper are useful for providing realistic motion for synthetic actors in computer animations and virtual environments and may someday be useful for analysis of sports performance.

Abstract: A camera tracking system determines the three dimensional (3D) location and orientation of the film plane of a camera providing live recording of a subject, thereby defining a 3D coordinate system of the live action scene into which animated objects or characters may be automatically mapped with proper scale and 3D visual object by a computer animation system.

Abstract: Sensing of human hand motion is very important for a variety of applications, such as computer animation and athletic performance measurement. Tracking a hand is difficult because the hand has high degree of freedom articulated mechanisms. This paper presents a 3D model-based hand tracking method which is robust to occlusions and local minima. Tracking is performed by minimizing the estimation error of an optical flow and maximizing the overlap between a projected model and a silhouette image. The authors employ stochastic optimization to solve them, which are generally difficult. They present experimental results on tracking from synthetic and real image sequences.

Abstract: Animation has been used in instruction for many years. However, recent advances permit the creation of desktop animations by a wider range of instructors. In order to understand the effects of animation on student learning and student reaction to it, an experimental study was conducted. A one-hour lesson on the 10th-grade mathematics topic of construction of triangles using a compass was developed in three instructional formats: (a) text only, (b) text plus static graphics, and (c) text plus animation. One hundred seventy four undergraduate elementary education majors were divided into high and low math achievement levels based on a pretest and randomly assigned to one of the three instructional groups. On a test designed to measure ability to construct triangles and identify trigonometric concepts, the animation group scored 21% and 35% higher than the graphics and text group, respectively. The graphics group scored higher than the text-only group. Attitude toward learning from CAI was equivalent...

Abstract: P usually type characters on a keyboard to enter, test, and debug computer programs. More than 30 years ago researchers began augmenting those characters with diagrams [20] but pure ASCII text is still the ubiquitous standard. We will argue that these attempts to make programming more visual have failed to become mainstream because they are too conservative. Various radical syntaxes for programs are feasible and offer many advantages over the state of the art. Programs, for example, can be defined by the topology of sketches, even hand-drawn scanned sketches [8]. A programming environment can parse these sketches and generate animations of the drawings that evolve as the program executes [6]. Or programs can be defined by manipulating physical objects, for example, by connecting blocks together [21] or inserting plastic cards into slots [17]. We are currently building a system called ToonTalk in which programs are created, run, and debugged in a manner that closely resembles playing a video game [7]. In the near future we may see program development systems that exist only in virtual reality or ones that interpret gestures in the real world. Program sources need not be static collections of text or even Drawings on Napkins, Video-Game Animation,and Other Ways to Program Computers K e n K a h n •

Abstract: From the Publisher: If you've tried your hand at 3-D computer graphics only to give up after wading through incomprehensible computer manuals that leave you confused and frustrated, you'll want to read The Art of 3-D Computer Animation and Imaging before calling in the consultants. The first of its kind, this book is a simple, non-platform-specific guide to 3-D computer design written in plain English by Isaac Victor Kerlow. Using a hands-on approach and many practical references, Kerlow guides you logically through the process of completing a fully rendered three-dimensional computer still image or animation. He explains every term, and points out common pitfalls of the creative and production process from the idea through post production. In addition to suggestions for implementing practical projects on a wide range of hardware and software platforms, The Art of 3-D Computer Animation and Imaging contains sections on creating and manipulating 3-D objects, actors and environments; full-color illustrations and step-by-step examples; a guide to the post-production process, including special effects, hypermedia formats, and video output; practical trouble-shooting tips; and chapter summaries for easy access to vital information. Whatever your hardware or software, you'll find practical help and creative inspiration here that will quickly put you on the road to creating your own 3-D computer images and animations.

Abstract: Consider the following problem: A viewpoint moves amongst a set of line segments in the plane and it is desired to maintain the sequence of lines visible from the viewpoint at every increment in its position. The sequence of visible lines is identical for most increments in the position of the viewpoint. It is different only when the viewpoint crosses a visual discontinuity line. Our objective is to be able to quickly report whether the sequence of visible lines needs to be updated and perform the update quickly in that case. We propose an algorithm that satisfies both criteria while using space linear in the number of visual discontinuity lines. This last condition is important because constructing the arrangement of these lines would take space quadratic in their number.

Abstract: Studies designed to demonstrate the pedagogic effectiveness of algorithm animation programs have been markedly unsuccessful, in spite of high expectations. We present a framework for future experiments based upon design issues particular to algorithm animation, plus pertinent educational considerations. Guidelines are drawn from a meta-analysis of previous work and experiments we have performed.

Abstract: The objective of this paper is to introduce a computer simulation model with on-screen animation graphics which can simulate the operations of a container terminal equipped with straddle carriers. The movements of the equipment are simulated as realistically as possible, to include time losses due to the mismatch in the sequence of equipment movements and to traffic congestion. Trucks are normally served in a special area, but in some cases, straddle carrier drivers can call the truck to be served directly in the container storage areas. The experience of operators is incorporated in the model, in the form of a knowledge base, that is used to simulate the above process and determine the service discipline. The model was designed to evaluate different configurations of the simulated system. The proposed model was used to examine the differences between "the observed" operations strategy and the strategy dictated by the operational rules of the port of Piraeus. The results indicate that "the observed" strategy leads to shorter truck service time but increases the traffic conflicts in the terminal's internal transportation networks.

Abstract: We present a formal theory of a behavioral L-system and describe as application a real time structured L-system interpreter. The behavioral L-system is a timed, conditional, stochastic, parametric and environmentally sensitive L-system which allows besides the modeling of plant and fractal development the description and animation of autonomous actors completely defined by production rules. A virtual environment including geometric objects, force fields and sounds and the behaviors of actors can be defined using the same formalism of the behavioral L-systems.

Abstract: The hierarchical control decomposition provided by inverse kinematics is seldom used in the field of Computer Animation. In this chapter we first review the properties and limitations of inverse kinematics compared to other techniques dedicated to the motion control of complex articulated figures. Then, beyond the sole pseudo-inverse solution, we examine the homogeneous solution allowing the partial realization of a secondary task (or optimization or behavior). Case studies are presented in two distinct application areas of this technique : balance control and motion correction.

Abstract: For cloth modeling and animation, we use a physically based model to simulate the dynamic formation of folds, pleats, and wrinkles and the final static appearance of cloth draped over a rigid object. To simulate the behavior of the cloth and its final static appearance on the model, we propose a new collision and self-collision avoidance method to prevent penetration between the cloth and rigid objects and between parts of the cloth. At each time step, we enforce constraints over those grid points about to penetrate other objects. Our method is easier and more robust than conventional methods at representing interaction between the cloth and various objects.

Abstract: The second edition of this popular reference addresses the newest techniques and latest technology in this rapidly changing field Comprehensive and non-platform specific, it cuts through technical jargon to offer clear, step-by-step guidance through the entire process of creating a fully rendered 3-D still image or animation Concepts are illustrated with 500 colour images - many of them new - from films, TV shows, and computer games The book covers creative and artistic needs of the graphic artist and the computer scientist/programmer In addition to dozens of new images, each chapter is fully updated and entirely new chapters on the overview of the digital production process and advanced character animation techniques are included Illustrations represent work by Pixar Animation Studios, Blue Sky Studios, Cyan, Inc, Disney Studios, MCA/Universal, Acclaim Entertainment, Midway Games, Inc, Rhythm & Hues Studios, and many more

Abstract: This thesis presents a computational framework and new algorithms for creating geometric models and images of physical objects. Our framework combines magnetic resonance imaging (MRI) research with image processing and volume visualization. One focus is feedback of requirements from later stages of the framework to earlier ones. Within the framework we measure physical objects yielding vector-valued MRI volume datasets. We process these datasets to identify different materials, and from the classified data we create images and geometric models. New algorithms developed within the framework include a goal-based technique for choosing MRI collection protocols and parameters and a family of Bayesian tissue-classification methods. The goal-based data-collection technique chooses MRI protocols and parameters subject to specific goals for the collected data. Our goals are to make identification of different tissues possible with data collected in the shortest possible time. Our method compares results across different collection protocols, and is fast enough to use for steering the data-collection process. Our new tissue-classification methods operate on small regions within a volume dataset, not directly on the sample points. We term these regions voxels and assume that each can contain a mixture of materials. The results of the classification step are tailored to make extraction of surface boundaries between solid object parts more accurate. Another new algorithm directly renders deformed volume data produced, for example, by simulating the movement of a flexible body. The computational framework for building geometric models allows computer graphics users to more easily create models with internal structure and with a high level of detail. Applications exist in a variety of fields including computer graphics modeling, biological modeling, anatomical studies, medical diagnosis, CAD/CAM, robotics, and computer animation. We demonstrate the utility of the computational framework with a set of computer graphics images and models created from data.