Abstract: Collision detection is a vital task in almost all forms of computer animation and physical simulation. It is also one of the most computationally expensive, and therefore a frequent impediment to efficient implementation of real-time graphics applications. We describe how graphics hardware can be used as a geometric co-processor to carry out the bulk of the computation involved with collision detection. Hardware frame buffer operations are used to implement a ray-casting algorithm which detects static interference between solid polyhedral objects. The algorithm is linear in both the number of objects and number of polygons in the models. It also requires no preprocessing or special data structures.

Abstract: We introduce a new interface for rapidly creating 3D articulated figure animation, from 2D sketches of the character in the desired key frame poses. Since the exact 3D animation corresponding to a set of 2D drawings is ambiguous we first reconstruct the possible 3D configurations and then apply a set of constraints and assumptions to present the user with the most likely 3D pose. The user can refine this candidate pose by choosing among alternate poses proposed by the system. This interface is supported by pose reconstruction and optimization methods specifically designed to work with imprecise hand drawn figures. Our system provides a simple, intuitive and fast interface for creating rough animations that leverages our users' existing ability to draw. The resulting key framed sequence can be exported to commercial animation packages for interpolation and additional refinement.

Abstract: This paper presents a vision of the near future in which computer interaction is characterized by natural face-to-face conversations with lifelike characters that speak, emote, and gesture. These animated agents will converse with people much like people converse effectively with assistants in a variety of focused applications. Despite the research advances required to realize this vision, and the lack of strong experimental evidence that animated agents improve human-computer interaction, we argue that initial prototypes of perceptive animated interfaces can be developed today, and that the resulting systems will provide more effective and engaging communication experiences than existing systems. In support of this hypothesis, we first describe initial experiments using an animated character to teach speech and language skills to children with hearing problems, and classroom subjects and social skills to children with autistic spectrum disorder. We then show how existing dialogue system architectures can be transformed into perceptive animated interfaces by integrating computer vision and animation capabilities. We conclude by describing the Colorado Literacy Tutor, a computer-based literacy program that provides an ideal testbed for research and development of perceptive animated interfaces, and consider next steps required to realize the vision.

Abstract: We discuss here a parallel implementation of the visualisation of data from a galaxy formation simulation within the Triana problem-solving environment. The visualisation is a test case for our prototype Triana Grid software using a decentralized peer-to-peer approach. The Triana distributed environment is middleware independent and designed in such a way as to make it easily extensible by users of the system. This novel approach is usable both within a peer-to-peer framework, using JXTA, and within service oriented architectures, such as OGSA, by the use of a Grid application toolkit (GAT) interface. Furthermore, Triana has a pluggable architecture that allows the middleware independent representations of distributed task-graphs to be written in several popular formats. This facilitates the use of the mechanism within other disparate systems. Galaxy-formation simulation codes generate data that represent a series of particles in three dimensions and their associate properties as snapshots in time. An important aspect of these types of calculation is the visualization of time sequence data. The user of the code would like to visualize this data as an animation in two dimensions with the ability to vary the point of view, project that particular two dimensional slice and re-run the animation. The recalculation of the projection can be computed in parallel resulting in a considerable speedup.

Abstract: Lifelike talking faces for interactive services are an exciting new modality for man-machine interactions. Recent developments in speech synthesis and computer animation enable the real-time synthesis of faces that look and behave like real people, opening opportunities to make interactions with computers more like face-to-face conversations. This paper focuses on the technologies for creating lifelike talking heads, illustrating the two main approaches: model-based animations and sample-based animations. The traditional model-based approach uses three-dimensional wire-frame models, which can be animated from high-level parameters such as muscle actions, lip postures, and facial expressions. The sample-based approach, on the other hand, concatenates segments of recorded videos, instead of trying to model the dynamics of the animations in detail. Recent advances in image analysis enable the creation of large databases of mouth and eye images, suited for sample-based animations. The sample-based approach tends to generate more naturally looking animations at the expense of a larger size and less flexibility than the model-based animations. Beside lip articulation, a talking head must show appropriate head movements, in order to appear natural. We illustrate how such "visual prosody" is analyzed and added to the animations. Finally, we present four applications where the use of face animation in interactive services results in engaging user interfaces and an increased level of trust between user and machine. Using an RTP-based protocol, face animation can be driven with only 800 bits/s in addition to the rate for transmitting audio.

Abstract: We implement a framework for animating interactive characters by combining kinematic animation with physical simulation. The combination of animation techniques allows the characters to exploit the advantages of each technique. For example, characters can perform natural-looking kinematic gaits and react dynamically to unexpected situations. Kinematic techniques such as those based on motion capture data can create very natural-looking animation. However, motion capture based techniques are not suitable for modeling the complex interactions between dynamically interacting characters. Physical simulation, on the other hand, is well suited for such tasks. Our work develops kinematic and dynamic controllers and transition methods between the two control methods for interactive character animation. In addition, we utilize the motion graph technique to develop complex kinematic animation from shorter motion clips as a method of kinematic control.

Abstract: Blend shape animation is the method of choice for keyframe facial animation: a set of blend shapes (key facial expressions) are used to define a linear space of facial expressions. However, in order to capture a significant range of complexity of human expressions, blend shapes need to be segmented into smaller regions where key idiosyncracies of the face being animated are present. Performing this segmentation by hand requires skill and a lot of time. In this paper, we propose an automatic, physically-motivated segmentation that learns the controls and parameters directly from the set of blend shapes. We show the usefulness and efficiency of this technique for both, motion-capture animation and keyframing. We also provide a rendering algorithm to enhance the visual realism of a blend shape model.

Abstract: A method is proposed in this paper to automatically generate the animation skeleton of a model such that the model can be manipulated according to the skeleton. With our method, users can construct the skeleton in a short time, and bring a static model both dynamic and alive. The primary steps of our method are finding skeleton joints, connecting the joints to form an animation skeleton, and binding skin vertices to the skeleton. Initially, a repulsive force field is constructed inside a given model, and a set of points with local minimal force magnitude are found based on the force field. Then, a modified thinning algorithm is applied to generate an initial skeleton, which is further refined to become the final result. When the skeleton construction completes, skin vertices are anchored to the skeleton joints according to the distances between the vertices and joints. In order to build the repulsive force field, hundreds of rays are shot radially from positions inside the model, and it leads to that the force field computation takes most of the execution time. Therefore, an octree structure is used to accelerate this process. Currently, the skeleton generated from a typical 3D model with 1000 to 10000 polygons takes less than 2 minutes on a Intel Pentium 4 2.4 GHz PC.

Abstract: We present a system for the automatic generation of bottom-up visual attention behaviours in virtual humans. Bottom-up attention refers to the way in which the environment solicits one's attention without regard to task-level goals. Our framework is based on the interactions of multiple components: a synthetic vision system for perceiving the virtual world, a model of bottom-up attention for early visual processing of perceived stimuli, a memory system for the storage of previously sensed data and a gaze controller for the generation of resultant behaviours. Our aim is to provide a feeling of presence in inhabited virtual environments by endowing agents with the ability to pay attention to their surroundings.

Abstract: Market acceptance of new personal computing products and services strongly depends on the quality of their user interfaces. Virtual reality is an emerging technology that promises significant advances in this area. The term itself is broad, ranging from simple 3D animation programs with no user interaction to systems with head-mounted displays, 3D manipulators, and other specialized hardware to immerse users in interactive virtual worlds. Originally developed for classic computer systems, VR technology is currently spreading to other platforms, including consumer electronics and interactive television systems. To enable the creation of active VR applications, we developed X-VRML. X-VRML is a high-level XML-based procedural language that adds dynamic modeling capabilities to virtual scene description standards such as VRML/X3D and MPEG-4.

Abstract: A system and method of converting frame-based animation into interpolator-based animation is provided. The system and method includes a) identifying each unique combination of animation object and associated depth identified in frame instructions for the plurality of frames of the frame-based animation; b) for each identified unique combination, identifying the display properties associated with the animation object of the combination through the successive frames; and c) for each identified display property for each identified unique combination, creating an intrepolar that specifies the animation object of the combination and any changes that occur in the display property for the specified animation object throughout the plurality of frames.

Abstract: We present Growing Polygons, a novel visualization technique for the graphical representation of causal relations and information flow in a system of interacting processes. Using this method, individual processes are displayed as partitioned polygons with color-coded segments showing dependencies to other processes. The entire visualization is also animated to communicate the dynamic execution of the system to the user. The results from a comparative user study of the method show that the Growing Polygons technique is significantly more efficient than the traditional Hasse diagram visualization for analysis tasks related to deducing information flow in a system for both small and large executions. Furthermore, our findings indicate that the correctness when solving causality tasks is significantly improved using our method. In addition, the subjective ratings of the users rank the method as superior in all regards, including usability, efficiency, and enjoyability.

Abstract: We present a generative model for textured motion phenomena, such as falling snow, wavy river and dancing grass, etc. Firstly, we represent an image as a linear superposition of image bases selected from a generic and over-complete dictionary. The dictionary contains Gabor bases for point/particle elements and Fourier bases for wave-elements. These bases compete to explain the input images. The transform from a raw image to a base or a token representation leads to large dimension reduction. Secondly, we introduce a unified motion equation to characterize the motion of these bases and the interactions between waves and particles, e.g. a ball floating on water. We use statistical learning algorithm to identify the structure of moving objects and their trajectories automatically. Then novel sequences can be synthesized easily from the motion and image models. Thirdly, we replace the dictionary of Gabor and Fourier bases with symbolic sketches (also bases). With the same image and motion model, we can render realistic and stylish cartoon animation. In our view, cartoon and sketch are symbolic visualization of the inner representation for visual perception. The success of the cartoon animation, in turn, suggests that our image and motion models capture the essence of visual perception of textured motion.

Abstract: There are many challenges associated with the integration of synthetic and real imagery. One particularly difficult problem is the automatic extraction of salient parameters of natural phenomena in real video footage for subsequent application to synthetic objects. We can ensure that the hair and clothing of a synthetic actor placed in a meadow of swaying grass will move consistently with the wind that moved that grass. The video footage can be seen as a controller for the motion of synthetic features, a concept we call video input driven animation (VIDA). We propose a schema that analyzes an input video sequence, extracts parameters from the motion of objects in the video, and uses this information to drive the motion of synthetic objects. To validate the principles of VIDA, we approximate the inverse problem to harmonic oscillation, which we use to extract parameters of wind and of regular water waves. We observe the effect of wind on a tree in a video, estimate wind speed parameters from its motion, and then use this to make synthetic objects move. We also extract water elevation parameters from the observed motion of boats and apply the resulting water waves to synthetic boats.

Abstract: The research goal at the Craniofacial Virtual Reality Laboratory of the School of Dentistry in conjunction with the Integrated Media Systems Center, School of Engineering, University of Southern California, is to develop computer methods to accurately visualize patients in three dimensions using advanced imaging and data acquisition devices such as cone-beam computerized tomography (CT) and mandibular motion capture. Data from these devices were integrated for three-dimensional (3D) patient-specific visualization, modeling and animation. Generic methods are in development that can be used with common CT image format (DICOM), mesh format (STL) and motion data (3D position over time). This paper presents preliminary descriptive studies on: 1) segmentation of the lower and upper jaws with two types of CT data--(a) traditional whole head CT data and (b) the new dental Newtom CT; 2) manual integration of accurate 3D tooth crowns with the segmented lower jaw 3D model; 3) realistic patient-specific 3D animation of the lower jaw.

Abstract: Motion blur is a well-established technique which prevents strobing by making fast moving objects appear blurred. In cel animation however, different methods are used and we present a new technique to emphasise the motion of cartoon objects through the application of geometry. We term the involved nonphotorealistic motion blur as 'cartoon blur'. In order to express cartoon blur, we have classified the expressions used in cel animation and analysed the diversity of each expression to establish parameters that allow animators to control the expression.

Abstract: This paper presents a method for animating and rendering an interactive natural scenery in real-time. It improves the prairie model of [I I I] by enabling the on-the-fly generation of blades of grass, at three different levels of detail, from user-specified density maps. A new animation function, the tread on grass, is defined to allow virtual objects or characters to crush the grass. The resulting grass model is incorporated into a more complex natural scene with the adjunction of trees that respond to the same wind. Results are illustrated by the real-time animation of autonomous virtual humans interacting with this natural scenery.

Abstract: We present a new system that applies an example-based learning method to learn facial motion patterns from a video sequence of individual facial behavior such as lip motion and facial expressions, and using that to create vivid three-dimensional (3-D) face animation according to the definition of MPEG-4 face animation parameters. The system consists of three key modules, face tracking, pattern learning, and face animation. In face tracking, to reduce the complexity of the tracking process, a novel coarse-to-fine strategy combined with a Kalman filter is proposed for localizing key facial landmarks in each image of the video. The landmarks' sequence is normalized into a visual feature matrix and then fed to the next step of process. In pattern learning, in the pretraining stage, the parameters of the camera that took the video are requested with the training video data so the system can estimate the basic mapping from a normalized two-dimensional (2-D) visual feature matrix to the representation in 3-D MPEG-4 face animation parameter space, in assistance with the computer vision method. In the practice stage, considering that in most cases camera parameters are not provided with video data, the system uses machine learning technology to complement the incomplete 3-D information for the mapping that information is needed in face orientation presentation. The example-based learning in this system integrates several methods including clustering, HMM, and ANN to make a better conversion from a 2-D to 3-D model and better estimation of incomplete 3-D information for good mapping; this will be used to drive face animation thereafter. In face animation, the system can synthesize face animation following any type of face motion in video. Experiments show that our system produces more vivid face motion animation, compared to other early systems.

Abstract: The reuse of motion capture data is receiving increasing attention in computer animation This interest is motivated by a wide spectrum of time-critical applications, such as video game development and animation production This paper gives an overview of various tasks and techniques involved in the reuse of motion capture data in terms of motion authoring pipeline We assume that whenever the user is asked to build motions, he/she will at first go to retrieve/browse the pre-recorded motions in the motion database, look for the best-fit candidate motion segments/pieces/clips, and manage to adapt them to fit the specified requirements The two core issues in motion reuse, motion adaptation techniques and motion library construction, are the focus of this review

Abstract: The Symposium on Computer Animation is an emerging, eminent forum for dissemination of the latest research results in computer animation The goal of the symposium is to provide an opportunity for researchers in computer animation to interact with one another, share new results, and discuss emerging directions for the field This year the Symposium on Computer Animation is co-located with SIGGRAPH and held just prior to the main conference in order to attract a broad range of participantsThese proceedings contain the 23 long papers and 15 short papers presented at the Symposium on Computer Animation, selected from over 100 submissions Each paper was reviewed by at least 5 members of the program committee and external reviewers The remarkable quality of the submissions made the final acceptance decision very difficult The selected papers cover a variety of topics ranging from physically-based simulation, facial and articulated body animation, motion capture and editing, natural phenomena and procedural modeling, animated arts and presentations, autonomous characters, and novel interfaces for animation

Abstract: Regardless of whether the humans involved are virtual or real, well-developed conversational skills are a necessity. The synthesis of interface agents that are not only understandable but also believable can be greatly aided by knowledge of which facial motions are perceptually necessary and sufficient for clear and believable conversational facial expressions. Here, we recorded several core conversational expressions (agreement, disagreement, happiness, sadness, thinking, and confusion) from several individuals, and then psychophysically determined the perceptual ambiguity and believability of the expressions. The results show that people can identify these expressions quite well, although there are some systematic patterns of confusion. People were also very confident of their identifications and found the expressions to be rather believable. The specific pattern of confusions and confidence ratings have strong implications for conversational animation. Finally, the present results provide the information necessary to begin a more fine-grained analysis of the core components of these expressions.

Abstract: We address the 3D tracking of pose and animation of the human face in monocular image sequences using active appearance models. The classical appearance-based tracking suffers from two disadvantages: (i) the estimated out-of-plane motions are not very accurate, and (ii) the convergence of the optimization process to desired minima is not guaranteed. We aim at designing an efficient active appearance model, which is able to cope with the above disadvantages by retaining the strengths of feature-based and featureless tracking methodologies. For each frame, the adaptation is split into two consecutive stages. In the first stage, the 3D head pose is recovered using robust statistics and a measure of consistency with a statistical model of a face texture. In the second stage, the local motion associated with some facial features is recovered using the concept of the active appearance model search. Tracking experiments and method comparison demonstrate the robustness and out-performance of the developed framework.

Abstract: We present an augmented reality system that relies on purely passive techniques to solve the real-time registration problem. It can run on a portable PC and does not require engineering of the environment, for example by adding markers. To achieve this result, we have integrated robust computer vision techniques into a powerful VR framework. The resulting AR system allows us to produce complex rendering and animation of virtual human characters, and to blend them into the real world. The system tracks the 3D camera position by means of a natural features tracker, which, given a rough CAD model, can deal with complex 3D objects. The tracking method can handle both large camera displacements and aspect changes. We will show that our system works in the cluttered environment of a real industrial facility and can, therefore, be used to enhance manufacturing and industrial processes.

Abstract: Preface 1 THE ANATOMY OF AN ADVANCED GAME SYSTEM I - THE BUILD PROCESS AND STATIC LIGHTING 1.1 Data Structures 1.2 The Build Process 1.3 Light Map Build 1.4 BSP Management 1.5 Advanced Static Lighting - Radiosity Appendix 1.1 Building In Practice Appendix 1.2 Basic Radiosity Theory 2 THE ANATOMY OF AN ADVANCED GAMES SYSTEM II - REAL-TIME PROCESSES 2.1 Viewing And The BSP 2.2 Camera Control 2.3 Generic Collision Detection And Response 2.4 Specialised Collision Detection And Response 2.5 Generic Path Planning Appendix 2.1 Demonstrations Of Real-Time Processes 3 THE ANATOMY OF AN ADVANCED GAMES SYSTEM III - SOFTWARE DESIGN AND APPLICATION PROGRAMMING 3.1 Types Of Applications 3.2 FLT3D Engine Architecture Appendix 3.1 Writing A Plug-In 4 REAL - TIME RENDERING 4.1 Introduction 4.2 Vertices, Pixels And Maps 4.3 Factorisation Methods 4.4 Brdfs And Real Materials 4.5 Per-Pixel Shading Using Brdfs 4.6 Environment Map Parameterisations 4.7 Implementing Brdfs: Separable Approximations 4.8 Shading Languages And Shaders 5 REAL - TIME RENDERING - PRACTICE 5.1 Basic Shaders 5.2 Render States 5.3 Shader Examples 5.4 Real-Time Rendering In Hardware 5.5 Dynamic Textures 5.6 Effects Appendix 5.1 Using And Experimenting With Shaders Appendix 5.2 Vertex Programming For NVIDIA Geforce3 Appendix 5.3 NVIDIA Register Combiner Operation 6 GEOMENTRY PROCESSING 6.1 Introduction 6.2 Motivating Factors And Definitions 6.3 Ordering Or Error Criteria 6.4 Simplification And Attributes 6.5 Case Studies Appendix 6.1 Mathematical Background Appendix 6.2 Demonstration 7 CHARACTER ANIMATION 7.1 Introduction 7.2 Vertex Animation And Blending 7.3 Skeleton Animation 7.4 Low-Level Animation Management Appendix 7.1 Using Quaternions To Represent Rotation Appendix 7.2 Implementing Quaternions Appendix 7.3 Efficiency Consideration In Character Animation (Optimising For SIMD Pentium3 Instructions) 8 ANIMATING SHAP - METHODS 8.1 Introduction 8.2 Spline Cages 8.3 Free Form Deformation (FFD) 8.4 Extended Free Form Deformations (Effds) 8.5 Curve Deformers - Wires 8.6 Skinning Revisited Appendix 8.1 Scattered Data Interpolation Using Radial Basis Functions 9 ELEMENTS OF ADVANCED CHARACTER ANIMATION 9.1 Introduction - An Anthropomorphic Interface For Games 9.2 Converting Linguistic Representations Into Animation - Examples 9.3 Facial Animation, Visual Speech And Tracking 9.4 Models For Controlling, Rendering And Tracking Facial Meshes 9.5 Visual Speech 9.6 Facial Animation And MPEG-4 9.7 Rendering Issues 9.8 Conclusions And Problems Appendix 9.1 A Pseudo-Muscle Model Implementation 10 ANIMATING CHARACTERS WITH MOTION CAPTURE 10.1 Introduction 10.2 Motion Data 10.3 Skeletons And Mocap - BVH Format 10.4 Basic Manipulation Of Motion Data 10.5 Interpolation In Mocap 10.6 Classic Signal Processing And Mocap 10.7 Signal Processing And Mocap Data 10.8 Motion Editing: Constraint-Based Approaches Appendix 10 1 Demonstration 11 INVERSE KINEMATICS: THE THEORY 11.1 An Example - The Two-Link Arm 11.2 The Jacobian 11.3 Approaches To IK 11.4 Practical Approaches To Inverse Kinematics References Index

Abstract: From the Publisher: If you work with or wish to use 3D computer animation, or want to gain a thorough and systematic understanding of computer animation - even if you have no prior knowledge of computers, computer graphics, mathematics, or programming - Principles of Three-Dimensional Computer Animation is for you. It explains, in terms laymen can understand, the general principles that underlie all 3D computer animation systems, without recourse to mathematical equations or programming code. This book is not a software manual. It does not deal with the specific implementation of the principles of three-dimensional computer animation by any one software package. Rather, it provides a thorough understanding of the basic concepts and techniques - modeling, rendering, animating, and recording to film and video - on which computer animation is based. With this knowledge in hand, you can quickly learn the operation of specific software packages. In addition to the fundamentals, the book covers advanced animation techniques and compositing and special effects, all of them found in commercially available software packages. Whether you are a beginning student of computer graphics or a professional involved in projects that involve 3D computer animation, you will find the information you need presented in a clear and readable style, illustrated with hundreds of drawings, diagrams, and renderings.

Abstract: The human body motion synthesis is highly necessary for humanoid robots' motion planning and computer animations. In this paper, new method for generating human-like natural motions based on the motion database acquired by motion capture systems is described. On the analysis step, the acquired motions are divided into some motion segments, and then the characteristic poses and motions are archived as 'motion styles'. The motion style is a kind of the human skill, and it's unique to the motions' scenario, such as the different kinds of dances. On the synthesis step, users direct the key poses of human figures. The system generates the characteristic motions according to the user's directions and motion style database. The experiment result shows that this method can synthesize the realistic 'stylized' motions with this framework.

Abstract: Introduction Getting equipped Getting animated Keep it simple - developing your story Coat hangers for armatures Model makers - the professionals Four walls and a sky - set and props Recording dialogue/lip sync/editing sound The mechanics of movement - animation The mechanics of performance Recording and/or filming Completing the story Getting the job - the business of animation Useful websites Animation festivals Animation training Suppliers Bibliography/filmographies.

Abstract: 3D circuit animations can be highly effective to understand and to visualize the interactions of components, voltages and currents in power electronics. With modern computer hardware and software tools, animations can be readily produced, and have been used to demonstrate power electronic circuit behavior. We introduce a new circuit animation system and the ideas behind it to the power electronics community. This animation system, offers potentially important advantages in showing the interactions of components, voltages, and currents in power-electronics circuits. We apply it to develop animations of rectifiers and DC/DC converters, and we report experience using them in a power electronics course.