SCA 13: Eurographics/SIGGRAPH Symposium on Computer Animation

Permanent URI for this collection


Preface and Table of Contents

Animating the Human Body

High Fidelity Facial Animation Capture and Retargeting With Contours

Bhat, Kiran S.
Goldenthal, Rony
Ye, Yuting
Mallet, Ronald
Koperwas, Michael
Animating the Human Body

Data-driven Glove Calibration for Hand Motion Capture

Wang, Yingying
Neff, Michael
Animating the Human Body

Virtual Character Performance From Speech

Marsella, Stacy
Xu, Yuyu
Lhommet, Margaux
Feng, Andrew
Scherer, Stefan
Shapirok, Ari
Character Animation: A Silly Walk through the Parkour

Diverse Motion Variations for Physics-based Character Animation

Agrawal, Shailen
Shen, Shuo
Panne, Michiel van de
Character Animation: A Silly Walk through the Parkour

Control of Rotational Dynamics for Ground Behaviors

Brown, David F.
Macchietto, Adriano
Yin, KangKang
Zordan, Victor
Character Animation: A Silly Walk through the Parkour

Relationship Descriptors for Interactive Motion Adaptation

Al-Asqhar, Rami Ali
Komura, Taku
Choi, Myung Geol
Using Rods for Ears, Hairs, and Spines

Artistic Simulation of Curly Hair

Iben, Hayley
Meyer, Mark
Petrovic, Lena
Soares, Olivier
Anderson, John
Witkin, Andrew
Using Rods for Ears, Hairs, and Spines

Rod Constraints for Simplified Ragdolls

Lewin, Chris
Thorman, Matt
Waterson, Tom
Williams, Chris
Willis, Phil
Using Rods for Ears, Hairs, and Spines

View-Dependent Control of Elastic Rod Simulation for 3D Character Animation

Koyama, Yuki
Igarashiy, Takeo
Smoke on the Water

Chimera Grids for Water Simulation

English, R. Elliot
Qiu, Linhai
Yu, Yue
Fedkiw, Ronald
Smoke on the Water

Consistent Surface Model for SPH-based Fluid Transport

Orthmann, Jens
Hochstetter, Hendrik
Bader, Julian
Bayraktar, Serkan
Kolb, Andreas
Smoke on the Water

A Hybrid Lagrangian-Eulerian Formulation for Bubble Generation and Dynamics

Patkar, Saket
Aanjaneya, Mridul
Karpman, Dmitriy
Fedkiw, Ronald
Agents Planning A Nice Walk

Multi-Domain Real-time Planning in Dynamic Environments

Kapadia, Mubbasir
Beacco, Alejandro
Garcia, Francisco
Reddy, Vivek
Pelechano, Nuria
Badler, Norman I.
Agents Planning A Nice Walk

Velocity-Based Modeling of Physical Interactions in Multi-Agent Simulations

Kim, Sujeong
Guy, Stephen J.
Manocha, Dinesh
Agents Planning A Nice Walk

SPREAD : Sound Propagation and Perception for Autonomous Agents in Dynamic Environments

Huang, Pengfei
Kapadia, Mubbasir
Badler, Norman I.
This Whole Mesh is Rigged

One-to-Many: Example-Based Mesh Animation Synthesis

Zheng, Changxi
This Whole Mesh is Rigged

Differential Blending for Expressive Sketch-Based Posing

Öztireli, A. Cengiz
Baran, Ilya
Popa, Tiberiu
Dalstein, Boris
Sumner, Robert W.
Gross, Markus
This Whole Mesh is Rigged

Efficient Simulation of Secondary Motion in Rig-Space

Hahn, Fabian
Thomaszewski, Bernhard
Coros, Stelian
Sumner, Robert W.
Gross, Markus
This Whole Mesh is Rigged

Geodesic Voxel Binding for Production Character Meshes

Dionne, Olivier
Lasa, Martin de
Bendy, Smoky, Smashy

A Level Set Method for Ductile Fracture

Hegemann, Jan
Jiang, Chenfanfu
Schroeder, Craig
Teran, Joseph M.
Bendy, Smoky, Smashy

Fast Deformation of Volume Data Using Tetrahedral Mesh Rasterization

Gascon, Jorge
Espadero, Jose M.
Perez, Alvaro G.
Torres, Rosell
Otaduy, Miguel A.
Bendy, Smoky, Smashy

Accurate Surface Embedding for Higher Order Finite Elements

Suwelack, Stefan
Lukarski, Dimitar
Heuveline, Vincent
Dillmann, Rüdiger
Speidel, Stefanie
Swimmers, Walkers and Creepy Crawlers

Modeling and Animating Myriapoda: A Real-Time Kinematic/Dynamic Approach

Fang, Jingyi
Jiang, Chenfanfu
Terzopoulos, Demetri
Swimmers, Walkers and Creepy Crawlers

Creature Features: Online motion puppetry for non-human characters

Seol, Yeongho
O'Sullivan, Carol
Lee, Jehee


BibTeX (SCA 13: Eurographics/SIGGRAPH Symposium on Computer Animation)
@inproceedings{
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Preface and Table of Contents}},
author = { year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = { }
@inproceedings{
10.1145:2485895.2485915,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
High Fidelity Facial Animation Capture and Retargeting With Contours}},
author = {
Bhat, Kiran S.
and
Goldenthal, Rony
and
Ye, Yuting
and
Mallet, Ronald
and
Koperwas, Michael
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485915}
}
@inproceedings{
10.1145:2485895.2485901,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Data-driven Glove Calibration for Hand Motion Capture}},
author = {
Wang, Yingying
and
Neff, Michael
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485901}
}
@inproceedings{
10.1145:2485895.2485900,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Virtual Character Performance From Speech}},
author = {
Marsella, Stacy
and
Xu, Yuyu
and
Lhommet, Margaux
and
Feng, Andrew
and
Scherer, Stefan
and
Shapirok, Ari
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485900}
}
@inproceedings{
10.1145:2485895.2485907,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Diverse Motion Variations for Physics-based Character Animation}},
author = {
Agrawal, Shailen
and
Shen, Shuo
and
Panne, Michiel van de
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485907}
}
@inproceedings{
10.1145:2485895.2485906,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Control of Rotational Dynamics for Ground Behaviors}},
author = {
Brown, David F.
and
Macchietto, Adriano
and
Yin, KangKang
and
Zordan, Victor
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485906}
}
@inproceedings{
10.1145:2485895.2485905,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Relationship Descriptors for Interactive Motion Adaptation}},
author = {
Al-Asqhar, Rami Ali
and
Komura, Taku
and
Choi, Myung Geol
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485905}
}
@inproceedings{
10.1145:2485895.2485913,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Artistic Simulation of Curly Hair}},
author = {
Iben, Hayley
and
Meyer, Mark
and
Petrovic, Lena
and
Soares, Olivier
and
Anderson, John
and
Witkin, Andrew
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485913}
}
@inproceedings{
10.1145:2485895.2485896,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Rod Constraints for Simplified Ragdolls}},
author = {
Lewin, Chris
and
Thorman, Matt
and
Waterson, Tom
and
Williams, Chris
and
Willis, Phil
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485896}
}
@inproceedings{
10.1145:2485895.2485898,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
View-Dependent Control of Elastic Rod Simulation for 3D Character Animation}},
author = {
Koyama, Yuki
and
Igarashiy, Takeo
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485898}
}
@inproceedings{
10.1145:2485895.2485897,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Chimera Grids for Water Simulation}},
author = {
English, R. Elliot
and
Qiu, Linhai
and
Yu, Yue
and
Fedkiw, Ronald
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485897}
}
@inproceedings{
10.1145:2485895.2485902,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Consistent Surface Model for SPH-based Fluid Transport}},
author = {
Orthmann, Jens
and
Hochstetter, Hendrik
and
Bader, Julian
and
Bayraktar, Serkan
and
Kolb, Andreas
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485902}
}
@inproceedings{
10.1145:2485895.2485912,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
A Hybrid Lagrangian-Eulerian Formulation for Bubble Generation and Dynamics}},
author = {
Patkar, Saket
and
Aanjaneya, Mridul
and
Karpman, Dmitriy
and
Fedkiw, Ronald
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485912}
}
@inproceedings{
10.1145:2485895.2485909,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Multi-Domain Real-time Planning in Dynamic Environments}},
author = {
Kapadia, Mubbasir
and
Beacco, Alejandro
and
Garcia, Francisco
and
Reddy, Vivek
and
Pelechano, Nuria
and
Badler, Norman I.
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485909}
}
@inproceedings{
10.1145:2485895.2485910,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Velocity-Based Modeling of Physical Interactions in Multi-Agent Simulations}},
author = {
Kim, Sujeong
and
Guy, Stephen J.
and
Manocha, Dinesh
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485910}
}
@inproceedings{
10.1145:2485895.2485911,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
SPREAD : Sound Propagation and Perception for Autonomous Agents in Dynamic Environments}},
author = {
Huang, Pengfei
and
Kapadia, Mubbasir
and
Badler, Norman I.
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485911}
}
@inproceedings{
10.1145:2485895.2485904,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
One-to-Many: Example-Based Mesh Animation Synthesis}},
author = {
Zheng, Changxi
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485904}
}
@inproceedings{
10.1145:2485895.2485916,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Differential Blending for Expressive Sketch-Based Posing}},
author = {
Öztireli, A. Cengiz
and
Baran, Ilya
and
Popa, Tiberiu
and
Dalstein, Boris
and
Sumner, Robert W.
and
Gross, Markus
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485916}
}
@inproceedings{
10.1145:2485895.2485918,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Efficient Simulation of Secondary Motion in Rig-Space}},
author = {
Hahn, Fabian
and
Thomaszewski, Bernhard
and
Coros, Stelian
and
Sumner, Robert W.
and
Gross, Markus
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485918}
}
@inproceedings{
10.1145:2485895.2485919,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Geodesic Voxel Binding for Production Character Meshes}},
author = {
Dionne, Olivier
and
Lasa, Martin de
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485919}
}
@inproceedings{
10.1145:2485895.2485908,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
A Level Set Method for Ductile Fracture}},
author = {
Hegemann, Jan
and
Jiang, Chenfanfu
and
Schroeder, Craig
and
Teran, Joseph M.
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485908}
}
@inproceedings{
10.1145:2485895.2485917,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Fast Deformation of Volume Data Using Tetrahedral Mesh Rasterization}},
author = {
Gascon, Jorge
and
Espadero, Jose M.
and
Perez, Alvaro G.
and
Torres, Rosell
and
Otaduy, Miguel A.
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485917}
}
@inproceedings{
10.1145:2485895.2485914,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Accurate Surface Embedding for Higher Order Finite Elements}},
author = {
Suwelack, Stefan
and
Lukarski, Dimitar
and
Heuveline, Vincent
and
Dillmann, Rüdiger
and
Speidel, Stefanie
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485914}
}
@inproceedings{
10.1145:2485895.2485899,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Modeling and Animating Myriapoda: A Real-Time Kinematic/Dynamic Approach}},
author = {
Fang, Jingyi
and
Jiang, Chenfanfu
and
Terzopoulos, Demetri
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485899}
}
@inproceedings{
10.1145:2485895.2485903,
booktitle = {
Eurographics/ ACM SIGGRAPH Symposium on Computer Animation},
editor = {
Theodore Kim and Robert Sumner
}, title = {{
Creature Features: Online motion puppetry for non-human characters}},
author = {
Seol, Yeongho
and
O'Sullivan, Carol
and
Lee, Jehee
}, year = {
2013},
publisher = {
ACM SIGGRAPH / Eurographics Association},
ISSN = {1727-5288},
ISBN = {978-1-4503-2132-7},
DOI = {
10.1145/2485895.2485903}
}

Browse

Recent Submissions

Now showing 1 - 25 of 25
  • Item
    Preface and Table of Contents
    (ACM SIGGRAPH / Eurographics Association, 2013) Theodore Kim and Robert Sumner
  • Item
    High Fidelity Facial Animation Capture and Retargeting With Contours
    (ACM SIGGRAPH / Eurographics Association, 2013) Bhat, Kiran S.; Goldenthal, Rony; Ye, Yuting; Mallet, Ronald; Koperwas, Michael; Theodore Kim and Robert Sumner
    Human beings are naturally sensitive to subtle cues in facial expressions, especially in areas of the eyes and mouth. Current facial motion capture methods fail to accurately reproduce motions in those areas due to multiple limitations. In this paper, we present a new performance capture method that focuses on the perceptually important contour features on the face. Additionally, the output of our two-step optimization scheme is also easily editable by an animator. To illustrate the strength of our system, we present a retargeting application that incorporates primary contour lines to map a performance with lip-sync from an actor to a creature.
  • Item
    Data-driven Glove Calibration for Hand Motion Capture
    (ACM SIGGRAPH / Eurographics Association, 2013) Wang, Yingying; Neff, Michael; Theodore Kim and Robert Sumner
    Hand motion is an important component of human motion, playing a central role in communication. However, it is difficult to capture hand motion optically, especially in conjunction with full body motion. Due to a lack of appropriate calibration methods, data gloves also do not provide sufficiently accurate hand motion. In this paper, we present a novel glove calibration approach that can map raw sensor readings to hand motion data with both accurate joint rotations and fingertip positions. Our method elegantly handles the sensor coupling problem by treating calibration as a flexible mapping from sensor readings to joint rotations. A sampling process collects data tuples according to accuracy requirements, and organizes all the tuples in a training set. From these data, a specially designed Gaussian Process Regression model is trained to infer the calibration function, and the learned model can be used to calibrate new sensor readings. For real-time hand motion capture, a sparse approximation of the model is used to enhance performance. Evaluation experiments demonstrate that our approach provides significantly better results that have more accurate hand shapes and fingertip positions, compared to other calibration methods.
  • Item
    Virtual Character Performance From Speech
    (ACM SIGGRAPH / Eurographics Association, 2013) Marsella, Stacy; Xu, Yuyu; Lhommet, Margaux; Feng, Andrew; Scherer, Stefan; Shapirok, Ari; Theodore Kim and Robert Sumner
    We demonstrate a method for generating a 3D virtual character performance from the audio signal by inferring the acoustic and semantic properties of the utterance. Through a prosodic analysis of the acoustic signal, we perform an analysis for stress and pitch, relate it to the spoken words and identify the agitation state. Our rule-based system performs a shallow analysis of the utterance text to determine its semantic, pragmatic and rhetorical content. Based on these analyses, the system generates facial expressions and behaviors including head movements, eye saccades, gestures, blinks and gazes. Our technique is able to synthesize the performance and generate novel gesture animations based on coarticulation with other closely scheduled animations. Because our method utilizes semantics in addition to prosody, we are able to generate virtual character performances that are more appropriate than methods that use only prosody. We perform a study that shows that our technique outperforms methods that use prosody alone.
  • Item
    Diverse Motion Variations for Physics-based Character Animation
    (ACM SIGGRAPH / Eurographics Association, 2013) Agrawal, Shailen; Shen, Shuo; Panne, Michiel van de; Theodore Kim and Robert Sumner
    We present an optimization framework for generating diverse variations of physics-based character motions. This allows for the automatic synthesis of rich variations in style for simulated jumps, flips, and walks. While well-posed motion optimization problems result in a single optimal motion, we explore using underconstrained motion descriptions and then optimizing for diversity. As input, the method takes a parameterized controller for a successful motion instance, a set of constraints that should be preserved, and a pairwise distance metric between motions. An offline optimization then produces a highly diverse set of motion styles for the same task. We demonstrate results for a variety of 2D and 3D physics-based motions and show that this approach can generate compelling new motions.
  • Item
    Control of Rotational Dynamics for Ground Behaviors
    (ACM SIGGRAPH / Eurographics Association, 2013) Brown, David F.; Macchietto, Adriano; Yin, KangKang; Zordan, Victor; Theodore Kim and Robert Sumner
    This paper proposes a physics-based framework to generate rolling behaviors with significant rotational components. The proposed technique is a general approach for guiding coordinated action that can be layered over existing control architectures through the purposeful regulation of specific whole-body features. Namely, we apply control for rotation through the specification and execution of specific desired 'rotation indices' for whole-body orientation, angular velocity and angular momentum control. We account for the stylistic components of behaviors through reference posture control. The novelty of the described work includes control over behaviors with considerable rotational components as well as a number of characteristics useful for general control, such as flexible posture tracking and contact control planning.
  • Item
    Relationship Descriptors for Interactive Motion Adaptation
    (ACM SIGGRAPH / Eurographics Association, 2013) Al-Asqhar, Rami Ali; Komura, Taku; Choi, Myung Geol; Theodore Kim and Robert Sumner
    This paper presents an interactive motion adaptation scheme for close interactions between skeletal characters and mesh structures, such as moving through restricted environments, and manipulating objects. This is achieved through a new spatial relationship-based representation, which describes the kinematics of the body parts by the weighted sum of translation vectors relative to points selectively sampled over the surfaces of the mesh structures. In contrast to previous discrete representations that either only handle static spatial relationships, or require offline, costly optimization processes, our continuous framework smoothly adapts the motion of a character to large updates of the mesh structures and character morphologies on-the-fly, while preserving the original context of the scene. The experimental results show that our method can be used for a wide range of applications, including motion retargeting, interactive character control and deformation transfer for scenes that involve close interactions. Our framework is useful for artists who need to design animated scenes interactively, and modern computer games that allow users to design their own characters, objects and environments.
  • Item
    Artistic Simulation of Curly Hair
    (ACM SIGGRAPH / Eurographics Association, 2013) Iben, Hayley; Meyer, Mark; Petrovic, Lena; Soares, Olivier; Anderson, John; Witkin, Andrew; Theodore Kim and Robert Sumner
    Artistic simulation of hair presents many challenges - ranging from incorporating artistic control to dealing with extreme motions of characters. Additionally, in a production environment, the simulation needs to be fast and results need to be usable ''out of the box'' (without extensive parameter modifications) in order to produce content efficiently. These challenges are only increased when simulating curly, stylized hair. We present a method for stably simulating stylized curly hair that addresses these artistic needs and performance demands. To satisfy the artistic requirement of maintaining the curl's helical shape during motion, we propose a hair model based upon an extensible elastic rod. We introduce a method for stably computing a frame along the hair curve, essential for stable simulation of curly hair. Our hair model uses a spring for controlling the bending of the curl and another for maintaining the helical shape during extension. We also address performance concerns often associated with handling hair-hair contact interactions by efficiently parallelizing the simulation. To do so, we present a technique for pruning both hair-hair contact pairs and hair particles. Our method has been used on two full length feature films and has proven to be robust and stable over a wide range of animated motion and on a variety of hair styles, from straight to wavy to curly. It has proven invaluable in providing controllable, stable and efficient simulation allowing our artists to achieve their desired performance even when facing strict scheduling demands.
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    Rod Constraints for Simplified Ragdolls
    (ACM SIGGRAPH / Eurographics Association, 2013) Lewin, Chris; Thorman, Matt; Waterson, Tom; Williams, Chris; Willis, Phil; Theodore Kim and Robert Sumner
    Physics-based animation has become a standard feature in modern games. Typically, the bones in a character's animation rig are each associated with a simulated rigid body, leading to a jointed assembly commonly called a ragdoll. The high density of animation bones in the spine area can cause instability and performance issues, so we are motivated to find a simplified physical representation for this region. We approximate the spine region of a ragdoll as an inextensible elastic curve, building a circular arc constraint based on the Kirchhoff rod model. Our simplified spine shows improved performance and stability over the standard group of socket joints, and proves to be more controllable. To model general elastic rods we use soft position constraints in place of forces, leading to a stable maximal coordinate formulation of inextensible Kirchhoff rods.
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    View-Dependent Control of Elastic Rod Simulation for 3D Character Animation
    (ACM SIGGRAPH / Eurographics Association, 2013) Koyama, Yuki; Igarashiy, Takeo; Theodore Kim and Robert Sumner
    This paper presents view-dependent control of elastic rod simulation for 3D character animation. Elastic rod simulation is often used in character animation to generate motion of passively deforming body parts such as hair, ear, and whiskers. Our goal is to allow artistic control of the simulation in a view-dependent way, for example to move a hair strand so that it does not hide the eye regardless of the view direction. To achieve this goal, the artist defines several example rest poses of the rod in preparation, each of which is associated with a particular view direction. In run time, the system computes the current rest pose by blending the example rest poses associated with the view directions near the current view direction, and then pulls the pose to the current rest pose. Technical contribution is in the formulation of example-based rod simulation using view direction as an input, and an algorithm to suppress undesirable increase of momentum caused by dynamically changing rest poses.
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    Chimera Grids for Water Simulation
    (ACM SIGGRAPH / Eurographics Association, 2013) English, R. Elliot; Qiu, Linhai; Yu, Yue; Fedkiw, Ronald; Theodore Kim and Robert Sumner
    We introduce a new method for large scale water simulation using Chimera grid embedding, which discretizes space with overlapping Cartesian grids that translate and rotate in order to decompose the domain into different regions of interest with varying spatial resolutions. Grids can track both fluid features and solid objects, allowing for dynamic spatial adaptivity without remeshing or repartitioning the domain. We solve the inviscid incompressible Navier- Stokes equations with an arbitrary-Lagrangian-Eulerian style semi- Lagrangian advection scheme and a monolithic SPD Poisson solver. We modify the particle level set method in order to adapt it to Chimera grids including particle treatment across grid boundaries with disparate cell sizes, and strategies to deal with locality in the implementation of the level set and fast marching algorithms. We use a local Voronoi mesh construction to solve for pressure and address a number of issues that arise with the treatment of the velocity near the interface. The resulting method is highly scalable on distributed parallel architectures with minimal communication costs.
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    Consistent Surface Model for SPH-based Fluid Transport
    (ACM SIGGRAPH / Eurographics Association, 2013) Orthmann, Jens; Hochstetter, Hendrik; Bader, Julian; Bayraktar, Serkan; Kolb, Andreas; Theodore Kim and Robert Sumner
    Surface effects play an essential role in fluid simulations. A vast number of dynamics including wetting of surfaces, cleansing, and foam dynamics are based on surface-surface and surface-bulk interactions, which in turn rely on a robust surface computation. In this paper we introduce a conservative Lagrangian formulation of surface effects based upon incompressible smoothed particle hydrodynamics (SPH). The key concept of our approach is to realize an implicit definition of the fluid's (free) surface by assigning each particle a value estimating its surface area. Based on this consistent surface representation, a conservative coupling of bulk and surface is achieved. We demonstrate the applicability and robustness of our approach for several types of surface-relevant effects including adsorption, diffusion and reaction kinetics.
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    A Hybrid Lagrangian-Eulerian Formulation for Bubble Generation and Dynamics
    (ACM SIGGRAPH / Eurographics Association, 2013) Patkar, Saket; Aanjaneya, Mridul; Karpman, Dmitriy; Fedkiw, Ronald; Theodore Kim and Robert Sumner
    We present a hybrid Lagrangian-Eulerian framework for simulating both small and large scale bubble dynamics, where the bubbles can grow or shrink in volume as dictated by pressure forces in the surrounding fluid. Small under-resolved bubbles are evolved using Lagrangian particles that are monolithically two-way coupled to the surrounding flow in a manner that closely approximates the analytic bubble oscillation frequency while converging to the analytic volume as predicted by the well-known Rayleigh-Plesset equation. We present a novel scheme for interconverting between these underresolved Lagrangian bubbles and larger well-resolved bubbles that are modeled with a traditional Eulerian level set approach. We also present a novel seeding mechanism to realistically generate bubbles when simulating fluid structure interaction with complex objects such as ship propellers. Moreover, our framework for bubble generation is general enough to be incorporated into all grid-based as well as particle-based fluid simulation methods.
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    Multi-Domain Real-time Planning in Dynamic Environments
    (ACM SIGGRAPH / Eurographics Association, 2013) Kapadia, Mubbasir; Beacco, Alejandro; Garcia, Francisco; Reddy, Vivek; Pelechano, Nuria; Badler, Norman I.; Theodore Kim and Robert Sumner
    This paper presents a real-time planning framework for multicharacter navigation that enables the use of multiple heterogeneous problem domains of differing complexities for navigation in large, complex, dynamic virtual environments. The original navigation problem is decomposed into a set of smaller problems that are distributed across planning tasks working in these different domains. An anytime dynamic planner is used to efficiently compute and repair plans for each of these tasks, while using plans in one domain to focus and accelerate searches in more complex domains. We demonstrate the benefits of our framework by solving many challenging multi-agent scenarios in complex dynamic environments requiring space-time precision and explicit coordination between interacting agents, by accounting for dynamic information at all stages of the decision-making process.
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    Velocity-Based Modeling of Physical Interactions in Multi-Agent Simulations
    (ACM SIGGRAPH / Eurographics Association, 2013) Kim, Sujeong; Guy, Stephen J.; Manocha, Dinesh; Theodore Kim and Robert Sumner
    We present an interactive algorithm to model physics-based interactions in multi-agent simulations. Our approach is capable of modeling both physical forces and interactions between agents and obstacles, while allowing the agents to anticipate and avoid collisions for local navigation. We combine velocity-based collision-avoidance algorithms with external physical forces. The overall formulation can approximately simulate various physical e?ects, including collisions, pushing, deceleration and resistive forces. We have integrated our approach with an open-source physics engine and use the resulting system to model plausible behaviors of and interactions among large numbers of agents in dense environments. Our algorithm can simulate a few thousand agents at interactive rates and can generate many emergent behaviors. The overall approach is useful for interactive applications that require plausible physical behavior, including games and virtual worlds.
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    SPREAD : Sound Propagation and Perception for Autonomous Agents in Dynamic Environments
    (ACM SIGGRAPH / Eurographics Association, 2013) Huang, Pengfei; Kapadia, Mubbasir; Badler, Norman I.; Theodore Kim and Robert Sumner
    The perception of sensory information and its impact on behavior is a fundamental component of being human. While visual perception is considered for navigation, collision, and behavior selection, the acoustic domain is relatively unexplored. Recent work in acoustics focuses on synthesizing sound in 3D environments; however, the perception of acoustic signals by a virtual agent is a useful and realistic adjunct to any behavior selection mechanism. In this paper, we present SPREAD, a novel agent-based sound perception model using a discretized sound packet representation with acoustic features including amplitude, frequency range, and duration. SPREAD simulates how sound packets are propagated, attenuated, and degraded as they traverse the virtual environment. Agents perceive and classify the sounds based on the locally-received packet set using a hierarchical clustering scheme, and have individualized hearing and understanding of their surroundings. Using this model, we demonstrate several simulations that greatly enrich controls and outcomes.
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    One-to-Many: Example-Based Mesh Animation Synthesis
    (ACM SIGGRAPH / Eurographics Association, 2013) Zheng, Changxi; Theodore Kim and Robert Sumner
    We propose an example-based approach for synthesizing diverse mesh animations. Provided a short clip of deformable mesh animation, our method synthesizes a large number of different animations of arbitrary length. Combining an automatically inferred linear blending skinning (LBS) model with a PCA-based model reduction, our method identifies possible smooth transitions in the example sequence. To create smooth transitions, we synthesize reduced deformation parameters based on a set of characteristic key vertices on the mesh. Furthermore, by analyzing cut nodes on a graph built upon the LBS model, we are able to decompose the mesh into independent components. Motions of these components are synthesized individually and assembled together. Our method has the complexity independent from mesh resolutions, enabling efficient generation of arbitrarily long animations without tedious parameter tuning and heavy computation. We evaluate our method on various animation examples, and demonstrate that numerous diverse animations can be generated from each single example.
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    Differential Blending for Expressive Sketch-Based Posing
    (ACM SIGGRAPH / Eurographics Association, 2013) Öztireli, A. Cengiz; Baran, Ilya; Popa, Tiberiu; Dalstein, Boris; Sumner, Robert W.; Gross, Markus; Theodore Kim and Robert Sumner
    Generating highly expressive and caricatured poses can be difficult in 3D computer animation because artists must interact with characters indirectly through complex character rigs. Furthermore, since caricatured poses often involve large bends and twists, artifacts arise with traditional skinning algorithms that are not designed to blend large, disparate rotations and cannot represent extremely large rotations. To overcome these problems, we introduce a differential blending algorithm that can successfully encode and blend large transformations, overcoming the inherent limitation of previous skeletal representations. Based on this blending method, we illustrate a sketch-based interface that supports curved bones and implements the line-of-action concept from hand-drawn animation to create expressive poses in 3D animation. By interpolating stored differential transformations across temporal keyframes, our system also generates caricatured animation. We present a detailed technical analysis of our differential blending algorithm and show several posing and animation results created using our system to demonstrate the utility of our method in practice.
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    Efficient Simulation of Secondary Motion in Rig-Space
    (ACM SIGGRAPH / Eurographics Association, 2013) Hahn, Fabian; Thomaszewski, Bernhard; Coros, Stelian; Sumner, Robert W.; Gross, Markus; Theodore Kim and Robert Sumner
    We present an efficient method for augmenting keyframed character animations with physically-simulated secondary motion. Our method achieves a performance improvement of one to two orders of magnitude over previous work without compromising on quality. This performance is based on a linearized formulation of rigspace dynamics that uses only rig parameters as degrees of freedom, a physics-based volumetric skinning method that allows our method to predict the motion of internal vertices solely from deformations of the surface, as well as a deferred Jacobian update scheme that drastically reduces the number of required rig evaluations. We demonstrate the performance of our method by comparing it to previous work and showcase its potential on a productionquality character rig.
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    Geodesic Voxel Binding for Production Character Meshes
    (ACM SIGGRAPH / Eurographics Association, 2013) Dionne, Olivier; Lasa, Martin de; Theodore Kim and Robert Sumner
    We propose a fully automatic method for specifying influence weights for closed-form skinning methods, such as linear blend skinning. Our method is designed to work with production meshes that may contain non-manifold geometry, be non-watertight, have intersecting triangles, or be comprise of multiple connected components. Starting from a character rest pose mesh and skeleton hierarchy, we first voxelize the input geometry. The resulting voxelization is then used to calculate binding weights, based on the geodesic distance between each voxel lying on a skeleton ''bone'' and all non-exterior voxels. This yields smooth weights at interactive rates, without time-constants, iteration parameters, or costly optimization at bind or pose time. By decoupling weight assignment from distance computation we make it possible to modify weights interactively, at pose time, without additional pre-processing or computation. This allows artists to assess impact of weight selection in the context in which they are used.
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    A Level Set Method for Ductile Fracture
    (ACM SIGGRAPH / Eurographics Association, 2013) Hegemann, Jan; Jiang, Chenfanfu; Schroeder, Craig; Teran, Joseph M.; Theodore Kim and Robert Sumner
    We utilize the shape derivative of the classical Griffith's energy in a level set method for the simulation of dynamic ductile fracture. The level set is defined in the undeformed configuration of the object, and its evolution is designed to represent a transition from undamaged to failed material. No re-meshing is needed since the resulting topological changes are handled naturally by the level set method. We provide a new mechanism for the generation of fragments of material during the progression of the level set in the Griffith's energy minimization. Collisions between different material pieces are resolved with impulses derived from the material point method over a background Eulerian grid. This provides a stable means for colliding with embedded interfaces. Simulation of corotational elasticity is based on an implicit finite element discretization.
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    Fast Deformation of Volume Data Using Tetrahedral Mesh Rasterization
    (ACM SIGGRAPH / Eurographics Association, 2013) Gascon, Jorge; Espadero, Jose M.; Perez, Alvaro G.; Torres, Rosell; Otaduy, Miguel A.; Theodore Kim and Robert Sumner
    Many inherently deformable structures, such as human anatomy, are often represented using a regular volumetric discretization, e.g., in medical imaging. While deformation algorithms employ discretizations that deform themselves along with the material, visualization algorithms are optimized for regular undeformed discretizations. In this paper, we propose a method to transform highresolution volume data embedded in a deformable tetrahedral mesh. We cast volume deformation as a problem of tetrahedral rasterization with 3D texture mapping. Then, the core of our solution to volume data deformation is a very fast algorithm for tetrahedral rasterization. We perform rasterization as a massively parallel operation on target voxels, and we minimize the number of voxels to be handled using a multi-resolution culling approach. Our method allows the deformation of volume data with over 20 million voxels at interactive rates.
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    Accurate Surface Embedding for Higher Order Finite Elements
    (ACM SIGGRAPH / Eurographics Association, 2013) Suwelack, Stefan; Lukarski, Dimitar; Heuveline, Vincent; Dillmann, Rüdiger; Speidel, Stefanie; Theodore Kim and Robert Sumner
    In this paper we present a novel approach to efficiently simulate the deformation of highly detailed meshes using higher order finite elements (FE). An efficient algorithm based on non-linear optimization is proposed in order to find the closest point in the curved computational FE mesh for each surface vertex. In order to extrapolate deformations to surface points outside the FE mesh, we introduce a mapping scheme that generates smooth surface deformations and preserves local shape even for low-resolution computational meshes. The mapping is constructed by representing each surface vertex in terms of points on the computational mesh and its distance to the FE mesh in normal direction. A numerical analysis shows that the mapping can be robustly constructed using the proposed non-linear optimization technique. Furthermore it is demonstrated that the numerical complexity of the mapping scheme is linear in the number of surface nodes and independent of the size of the coarse computational mesh.
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    Modeling and Animating Myriapoda: A Real-Time Kinematic/Dynamic Approach
    (ACM SIGGRAPH / Eurographics Association, 2013) Fang, Jingyi; Jiang, Chenfanfu; Terzopoulos, Demetri; Theodore Kim and Robert Sumner
    Unlike two, four, six, and eight legged animals, Myriapoda-i.e., centipedes, millipedes, etc.-have been largely overlooked in the computer graphics literature. We present an artificial life framework for modeling these arthropods and animating their locomotive behavior over regular or irregular surfaces in real time with compelling physical and biological realism. Our hybrid approach combines kinematic and dynamic simulation, as well as a decentralized, distributed leg control system whose emergent behavior is suitable for animating simulated myriapoda of different morphologies with the characteristically vivid leg wave patterns of their biological counterparts. The simulated creature's antennae sense its virtual environment and the sensory information guides its adaptive behaviors, including obstacle avoidance and foraging.
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    Creature Features: Online motion puppetry for non-human characters
    (ACM SIGGRAPH / Eurographics Association, 2013) Seol, Yeongho; O'Sullivan, Carol; Lee, Jehee; Theodore Kim and Robert Sumner
    We present a novel real-time motion puppetry system that drives the motion of non-human characters using human motion input. We aim to control a variety of creatures whose body structures and motion patterns can differ greatly from a human's. A combination of direct feature mapping and motion coupling enables the generation of natural creature motion, along with intuitive and expressive control for puppetry. First, in the design phase, direct feature mappings and motion classification can be efficiently and intuitively computed given crude motion mimicking as input. Later, during the puppetry phase, the user's body motions are used to control the target character in real-time, using the combination of feature mappings generated from the design phase. We demonstrate the effectiveness of our approach with several examples of natural puppetry, where a variety of non-human creatures are controlled in real-time using human motion input from a commodity motion sensing device.