When several objects are moved about by computer ani-marion, there is the chance that they will interpenetrate. This is often an undesired state, particularly if the animation is seeking to model a realistic world. Two issues are involved: detecting that a collision has occurred, and responding to it. The former is fundamentally a kinematic problem, involving the positional relationship of objects in the world. The latter is a dynamic problem, in that it involves predicting behavior according to physical laws. This paper discusses collision detection and response in general, presents two collision detection algorithms, describes modeling collisions of arbi-trary bodies using springs, and presents an analytical collision response algorithm for articulated rigid bodies that conserves linear and angular momentum.

We present a paradigm and toolkit for rapid prototyping of interactive, animated 3D graphics programs. The paradigm has its roots in declarative programming, emphasizing immutable values, first class functions, and relations, applying these concepts to a broad range of types, including points, vectors, planes, colors, transforms, geometry, and sound. The narrow role of modifiable state in this paradigm allows applications to be run in a collaborative setting (multi-user and multi-computer) without modification. CR Categories and Subject Descriptors: I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism; I.3.6 [Computer Graphics]: Methodology and Techniques; D.1.1 [Pro- gramming Techniques] Applicative (Functional) Programming; D.2.m [Software Engineering] Miscellaneous Rapid Prototyping; G.1.7 [Mathematics of Computing] Ordinary Differential Equations. Additional Keywords and Phrases: Local Propagation Constraints 1 Introduction TBAG is a paradigm and toolkit for ra...

The use of physically-based techniques for computer animation can result in realistic object motion. The price paid for physically-based motion synthesis lies in increased computation and information re-quirements. We introduce a new approach to realistic motion spec-ification based on state-space controllers. A user specifies a motion by defining a goal in terms of a set of destination states. A state-space controller is then constructed, which provides an optimal-control solution that guides the object from an arbitrary starting con-figuration to a goal. Motions are optimized with respect to time and control energy. Because controllers are specified in terms of desti-nation states only, it is easy to reuse the same controller to produce different motions (from different starting states), or to create a com-plex sequence of motions by concatenating several controllers. An implementation of state-space controllers is presented, in which re-alistic motions can be produced in real time. Several examples will be considered.

Object orientation and concurrency are inherent to computer animation. Since the pieces of an animation can come from various media such as computer-generated imagery, video, and sound, the case for object orientation is all the stronger. However, languages for expressing the temporal co-ordination of animated objects have been slow in coming. We present such a language in this paper. Since the movements that an animated object can perform are also encapsulated as objects in our system, the scripting language can also be used to specify motion co-ordination. Such "motion objects" can be applied to any animated object. The syntax, semantics, and implementation of this language will be described, and we shall show how to specify device-independent computer animation. 1 Introduction The term "object" has become a very popular buzzword. Interpretations vary as to what precisely constitutes an object-oriented system. We view an object as being an encapsulation of activities and data. Its b...

Creating Animation for Presentations by Douglas Zongker Chair of Supervisory Committee: Professor David H. Salesin Computer Science & Engineering In recent years the use of computer-generated slides to accompany live presentation has become increasingly common. There is a potential for using computer graphics to increase the effectiveness of this type of presentation. The hardware for generating and projecting complex scenes and animation is in place, yet few efforts have been made in creating software to fully utilize these capabilities.

Animating human-like characters is a recurring issue in computer graphics. Recently, capturing live motion has become one of the most promising technologies in character animation. Due to the success of this technology, realistic and highly detailed motion data are rapidly spread in computer graphics applications. Crafting animation with such data requires a rich set of specialized tools such as interactive editing, retargetting, blending, stitching, smoothing, enhancing,up-ing,W4G6 downsampling and so on. With those tools, animators combine motion clips together into animations of arbitrary length with great variety in character size, environment geometry, and scenario. A typical process of producing animation from live-BE5P7WM data includes three major steps: The first step is to filter the raw input signal received from a motion capture system to obtain smoother, pleasing motion data. The next is to adapt the motion data to fit into a specific character or a virtual environment that...

Arctic is a langu-~ge for tile specification and imp!ementation of real-time control systems. Unlike more conventional languages for real-time control, which emphasize concurrency, Arctic is a stateless language in which the relationships between system inputs, outputs and intermediate terms are expressed as operation. ~ on time-varying functions. Arctic allows discrete events or conditions to invoke and modify responses asynchronously, but because programs have no state, synchronization problems are greatly simplified. Furthermore, Arctic programs are non-sequential, and the timing of system responses is notated explicitly. This eliminates the need for the programmer to be concerned with the execution sequence, which accounts for much of the difficulty in real-time programming. 1.

Abstract--This paper presents an interactive system for motion control that emphasizes object interaction. The fundamental mechanism provided to support interaction between objects is thefield. We present a new technique called dynamic splines which dynamically generates a trajectory under field control. Dynamic splines mimic the kinematic behaviour of a particle moving in a field, yet, it is computationally inexpensive compared to full physical dynamic approaches. We also show how to extend the field approach to specify tracking behaviour. 1.

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We present an unsupervised approach to automated story picturing. Semantic keywords are extracted from the story, an annotated image database is searched. Thereafter, a novel image ranking scheme automatically determines the importance of each image. Both lexical annotations and visual content play a role in determining the ranks. Annotations are processed using the Wordnet. A mutual reinforcement-based rank is calculated for each image. We have implemented the methods in our Story Picturing Engine (SPE) system. Experiments on large-scale image databases are reported. A user study has been performed and statistical analysis of the results has been presented.