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Character Animation (character + animation)

Distribution by Scientific Domains
Information Science and Computing85%

Selected Abstracts

ProcDef: Local-to-global Deformation for Skeleton-free Character Animation

COMPUTER GRAPHICS FORUM, Issue 7 2009
Takashi Ijiri
Abstract Animations of characters with flexible bodies such as jellyfish, snails, and, hearts are difficult to design using traditional skeleton-based approaches. A standard approach is keyframing, but adjusting the shape of the flexible body for each key frame is tedious. In addition, the character cannot dynamically adjust its motion to respond to the environment or user input. This paper introduces a new procedural deformation framework (ProcDef) for designing and driving animations of such flexible objects. Our approach is to synthesize global motions procedurally by integrating local deformations. ProcDef provides an efficient design scheme for local deformation patterns; the user can control the orientation and magnitude of local deformations as well as the propagation of deformation signals by specifying line charts and volumetric fields. We also present a fast and robust deformation algorithm based on shape-matching dynamics and show some example animations to illustrate the feasibility of our framework. [source]

Local Physical Models for Interactive Character Animation

COMPUTER GRAPHICS FORUM, Issue 3 2002
Sageev Oore
Our goal is to design and build a tool for the creation of expressive character animation. Virtual puppetry, also known as performance animation, is a technique in which the user interactively controls a character's motion. In this paper we introduce local physical models for performance animation and describe how they can augment an existing kinematic method to achieve very effective animation control. These models approximate specific physically-generated aspects of a character's motion. They automate certain behaviours, while still letting the user override such motion via a PD-controller if he so desires. Furthermore, they can be tuned to ignore certain undesirable effects, such as the risk of having a character fall over, by ignoring corresponding components of the force. Although local physical models are a quite simple approximation to real physical behaviour, we show that they are extremely useful for interactive character control, and contribute positively to the expressiveness of the character's motion. In this paper, we develop such models at the knees and ankles of an interactively-animated 3D anthropomorphic character, and demonstrate a resulting animation. This approach can be applied in a straight-forward way to other joints. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism, Interaction Techniques [source]

Extended spatial keyframing for complex character animation

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2008
Byungkuk Choi
Abstract As 3D computer animation becomes more accessible to novice users, it makes it possible for these users to create high-quality animations. This paper introduces a more powerful system to create highly articulated character animations with an intuitive setup then the previous research, Spatial Keyframing (SK). As the main purpose of SK was the rapid generation of primitive animation over quality animation, we propose Extended Spatial Keyframing (ESK) that exploits a global control structure coupled with multiple sets of spatial keyframes, and hierarchical relationship between controllers. The generated structure can be flexibly embedded into the given rigged character, and the system enables the given character to be animated delicately by user performance. During the performance, the movement of the highest ranking controllers across the control hierarchy is recorded in layered style to increase the level of detail for final motions. Copyright © 2008 John Wiley & Sons, Ltd. [source]

A grasp-based motion planning algorithm for character animation

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3 2001
Maciej Kalisiak
The design of autonomous characters capable of planning their own motions continues to be a challenge for computer animation. We present a novel kinematic motion-planning algorithm for character animation which addresses some of the outstanding problems. The problem domain for our algorithm is as follows: given a constrained environment with designated handholds and footholds, plan a motion through this space towards some desired goal. Our algorithm is based on a stochastic search procedure which is guided by a combination of geometric constraints, posture heuristics, and distance-to-goal metrics. The method provides a single framework for the use of multiple modes of locomotion in planning motions through these constrained, unstructured environments. We illustrate our results with demonstrations of a human character using walking, swinging, climbing, and crawling in order to navigate through various obstacle courses. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Local Physical Models for Interactive Character Animation

COMPUTER GRAPHICS FORUM, Issue 3 2002
Sageev Oore
Our goal is to design and build a tool for the creation of expressive character animation. Virtual puppetry, also known as performance animation, is a technique in which the user interactively controls a character's motion. In this paper we introduce local physical models for performance animation and describe how they can augment an existing kinematic method to achieve very effective animation control. These models approximate specific physically-generated aspects of a character's motion. They automate certain behaviours, while still letting the user override such motion via a PD-controller if he so desires. Furthermore, they can be tuned to ignore certain undesirable effects, such as the risk of having a character fall over, by ignoring corresponding components of the force. Although local physical models are a quite simple approximation to real physical behaviour, we show that they are extremely useful for interactive character control, and contribute positively to the expressiveness of the character's motion. In this paper, we develop such models at the knees and ankles of an interactively-animated 3D anthropomorphic character, and demonstrate a resulting animation. This approach can be applied in a straight-forward way to other joints. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism, Interaction Techniques [source]

MPEG-4 facial animation in video analysis and synthesis

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 5 2003
Peter Eisert
Abstract MPEG-4 supports the definition, encoding, transmission, and animation of 3-D head and body models. These features can be used for a variety of different applications ranging from low bit-rate video coding to character and avatar animation. In this article, an entire system for the analysis of facial expressions from image sequences and their synthesis is presented. New methods for the estimation of MPEG-4 facial animation parameters as well as scene illumination are proposed. Experiments for different applications demonstrate the potential of using facial animation techniques in video analysis and synthesis. A model-based codec is presented that is able to encode head-and-shoulder video sequences at bit-rates of about 1 kbit/s. Besides the low bit-rate, many enhancements and scene modifications can be easily applied, like scene lighting changes or cloning of expressions for character animation. But also for the encoding of arbitrary sequences, 3-D knowledge can help to increase the coding efficiency. With our model-aided codec, bit-rate reductions of up to 45% at the same quality can be achieved in comparison to standard hybrid video codecs. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 245,256, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10072 [source]