Computer Graphics

University of California - Berkeley

James F. O'Brien

List of Publications


Author's Homepage
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2014


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Exposing Photo Manipulation from Shading and Shadows

Eric Kee, James F. O'Brien, Hany Farid
TOG 2014

We describe a method for detecting physical inconsistencies in lighting from the shading and shadows in an image. This method imposes a multitude of shading- and shadow-based ... [more]


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Adaptive Tearing and Cracking of Thin Sheets

Tobias Pfaff, Rahul Narain, Juan Miguel de Joya, James F. O'Brien
SIGGRAPH 2014

This paper presents a method for adaptive fracture propagation in thin sheets. A high-quality triangle mesh is dynamically restructured to adaptively maintain detail ... [more]


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Self-Refining Games using Player Analytics

Matt Stanton, Ben Humberston, Brandon Kase, James F. O'Brien, Kayvon Fatahalian, Adrien Treuille
SIGGRAPH 2014

Data-driven simulation demands good training data drawn from a vast space of possible simulations. While fully sampling these large spaces is infeasible, we observe that ... [more]


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View-Dependent Adaptive Cloth Simulation

Woojong Koh, Rahul Narain, James F. O'Brien
SCA 2014

This paper describes a method for view-dependent cloth simulation using dynamically adaptive mesh refinement and coarsening. Given a prescribed camera motion, the method ... [more]

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2013


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Fast Simulation of Mass-Spring Systems

Tiantian Liu, Adam Bargteil, James F. O'Brien, Ladislav Kavan
SIGGRAPH Asia 2013

We describe a scheme for time integration of mass-spring systems that makes use of a solver based on block coordinate descent. This scheme provides a fast solution for classical ... [more]


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Exposing Photo Manipulation with Inconsistent Shadows

Eric Kee, James F. O'Brien, Hany Farid
TOG 2013

We describe a geometric technique to detect physically inconsistent arrangements of shadows in an image. This technique combines multiple constraints from cast and attached ... [more]


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Folding and Crumpling Adaptive Sheets

Rahul Narain, Tobias Pfaff, James F. O'Brien
SIGGRAPH 2013

We present a technique for simulating plastic deformation in sheets of thin materials, such as crumpled paper, dented metal, and wrinkled cloth. Our simulation uses a framework ... [more]


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Near-exhaustive Precomputation of Secondary Cloth Effects

Doyub Kim, Woojong Koh, Rahul Narain, Kayvon Fatahalian, Adrien Treuille, James F. O'Brien
SIGGRAPH 2013

The central argument against data-driven methods in computer graphics rests on the curse of dimensionality: it is intractable to precompute "everything" about a complex ... [more]


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Simulating Liquids and Solid-Liquid Interactions with Lagrangian Meshes

Pascal Clausen, Martin Wicke, Jonathan Shewchuk, James F. O'Brien
TOG 2013

This paper describes a Lagrangian finite element method that simulates the behavior of liquids and solids in a unified framework. Local mesh improvement operations maintain ... [more]

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2012


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Adaptive Anisotropic Remeshing for Cloth Simulation

Rahul Narain, Armin Samii, James F. O'Brien
SIGGRAPH Asia 2012

We present a technique for cloth simulation that dynamically refines and coarsens triangle meshes so that they automatically conform to the geometric and dynamic detail ... [more]


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Updated Sparse Cholesky Factors for Corotational Elastodynamics

Florian Hecht, Yeon Jin Lee, Jonathan Shewchuk, James F. O'Brien
TOG 2012

We present warp-canceling corotation, a nonlinear finite element formulation for elastodynamic simulation that achieves fast performance by making only partial or ... [more]


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Exposing Digital Forgeries in Ballistic Motion

Valentina Conotter, James F. O'Brien, Hany Farid
TIFS 2012

We describe a geometric technique to detect physically implausible trajectories of objects in video sequences. This technique explicitly models the three-dimensional ... [more]


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Exposing Photo Manipulation with Inconsistent Reflections

James F. O'Brien, Hany Farid
TOG 2012

The advent of sophisticated photo editing software has made it increasingly easier to manipulate digital images. Often visual inspection cannot definitively distinguish ... [more]

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2011


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Data-Driven Elastic Models for Cloth: Modeling and Measurement

Huamin Wang, Ravi Ramamoorthi, James F. O'Brien
SIGGRAPH 2011

Cloth often has complicated nonlinear, anisotropic elastic behavior due to its woven pattern and fiber properties. However, most current cloth simulation techniques simply ... [more]


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Perceptually Based Tone Mapping for Low-Light Conditions

Adam Kirk, James F. O'Brien
SIGGRAPH 2011

In this paper we present a perceptually based algorithm for modeling the color shift that occurs for human viewers in low-light scenes. Known as the Purkinje effect, this ... [more]


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Bringing Clothing into Desired Configurations with Limited Perception

Marco Cusumano-Towner, Arjun Singh, Stephen Miller, James F. O'Brien, Pieter Abbeel
ICRA 2011

We consider the problem of autonomously bringing an article of clothing into a desired configuration using a general-purpose two-armed robot. We propose a hidden Markov ... [more]


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Modeling and Perception of Deformable One-Dimensional Objects

Shervin Javdani, Sameep Tandon, Jie Tang, James F. O'Brien, Pieter Abbeel
ICRA 2011

Recent advances in the modeling of deformable one-dimensional objects (DOOs) such as surgical suture, rope, and hair show significant promise for improving the simulation ... [more]

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2010


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Multi-Resolution Isotropic Strain Limiting

Huamin Wang, James F. O'Brien, Ravi Ramamoorthi
SIGGRAPH Asia 2010

In this paper we describe a fast strain-limiting method that allows stiff, incompliant materials to be simulated efficiently. Unlike prior approaches, which act on springs ... [more]


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Example-Based Wrinkle Synthesis for Clothing Animation

Huamin Wang, Florian Hecht, Ravi Ramamoorthi, James F. O'Brien
SIGGRAPH 2010

This paper describes a method for animating the appearance of clothing, such as pants or a shirt, that fits closely to a figure's body. Compared to flowing cloth, such as loose ... [more]


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Dynamic Local Remeshing for Elastoplastic Simulation

Martin Wicke, Daniel Ritchie, Bryan Klingner, Sebastian Burke, Jonathan Shewchuk, James F. O'Brien
SIGGRAPH 2010

We propose a finite element simulation method that addresses the full range of material behavior, from purely elastic to highly plastic, for physical domains that are substantially ... [more]


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Simulation of Needle Insertion and Tissue Deformation for Modeling Prostate Brachytherapy

Nuttapong Chentanez, Ron Alterovitz, Daniel Ritchie, Lita Cho, Kris Hauser, Ken Goldberg, Jonathan Shewchuk, James F. O'Brien
ABS 2010

Realistic modeling of needle insertion during brachytherapy can be used for training and in automated planning to reduce errors between intended and actual placement ... [more]


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Using Blur to Affect Perceived Distance and Size

Robert (Robin) Held, Emily Cooper, James F. O'Brien, Marty Banks
TOG 2010

We present a probabilistic model of how viewers may use defocus blur in conjunction with other pictorial cues to estimate the absolute distances to objects in a scene. Our ... [more]

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2009


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Generating Surface Crack Patterns

Hayley Iben, James F. O'Brien
Graphical Models

We present a method for generating surface crack patterns that appear in materials such as mud, ceramic glaze, and glass. To model these phenomena, we build upon existing physically ... [more]


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Interactive Simulation of Surgical Needle Insertion and Steering

Nuttapong Chentanez, Ron Alterovitz, Daniel Ritchie, Lita Cho, Kris Hauser, Ken Goldberg, Jonathan Shewchuk, James F. O'Brien
SIGGRAPH 2009

We present algorithms for simulating and visualizing the insertion and steering of needles through deformable tissues for surgical training and planning. Needle insertion ... [more]


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Real-Time Deformation and Fracture in a Game Environment

Eric G. Parker, James F. O'Brien
SCA 2009

This paper describes a simulation system that has been developed to model the deformation and fracture of solid objects in a real-time gaming context. Based around a corotational ... [more]


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Refolding Planar Polygons

Hayley Iben, James F. O'Brien, Erik Demaine
DCG

This paper describes an algorithm for generating a guaranteed intersection-free interpolation sequence between any pair of compatible polygons. Our algorithm builds ... [more]

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2008


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Making Big Things Look Small: Blur combined with other depth cues affects perceived size and distance

Robert (Robin) Held, Emily Cooper, James F. O'Brien, Marty Banks
VSS 2008

Blur is commonly considered a weak distance cue, but photographic techniques that manipulate blur cause significant and compelling changes in the perceived distance ... [more]

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2007


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Liquid Simulation on Lattice-Based Tetrahedral Meshes

Nuttapong Chentanez, Bryan Feldman, François Labelle, James F. O'Brien, Jonathan Shewchuk
SCA 2007

This paper describes a simulation method for animating the behavior of incompressible liquids with complex free surfaces. The region occupied by the liquid is discretized ... [more]


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A Method for Cartoon-Style Rendering of Liquid Animations

Ashley M. Eden, Adam Bargteil, Tolga Goktekin, Sara Beth Eisinger, James F. O'Brien
GI 2007

In this paper we present a visually compelling and informative cartoon rendering style for liquid animations. Our style is inspired by animations such as Futurama, The Little ... [more]

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2006


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A semi-Lagrangian contouring method for fluid simulation

Adam Bargteil, Tolga Goktekin, James F. O'Brien, John A. Strain
ACM Trans. Graphics

In this paper we present a semi-Lagrangian surface tracking method for use with fluid simulations. Our method maintains an explicit polygonal mesh that defines the surface ... [more]


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Optimization of HDR brachytherapy dose distributions using linear programming with penalty costs

Ron Alterovitz, Etienne Lessard, Jean Pouliot, I-Chow Joe Hsu, James F. O'Brien, Ken Goldberg
J. Medical Physics

Prostate cancer is increasingly treated with high-dose-rate (HDR) brachytherapy, a type of radiotherapy in which a radioactive source is guided through catheters temporarily ... [more]


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A Texture Synthesis Method for Liquid Animations

Adam Bargteil, Funshing Sin, Jonathan E. Michaels, Tolga Goktekin, James F. O'Brien
SCA 2006

In this paper we present a method for synthesizing textures on animated liquid surfaces generated by a physically based fluid simulation system. Rather than advecting ... [more]


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Generating Surface Crack Patterns

Hayley Iben, James F. O'Brien
SCA 2006

We present a method for generating surface crack patterns that appear in materials such as mud, ceramic glaze, and glass. To model these phenomena, we build upon existing physically ... [more]


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Simultaneous Coupling of Fluids and Deformable Bodies

Nuttapong Chentanez, Tolga Goktekin, Bryan Feldman, James F. O'Brien
SCA 2006

This paper presents a method for simulating the two-way interaction between fluids and deformable solids. The fluids are simulated using an incompressible Eulerian formulation ... [more]


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Fluid Animation with Dynamic Meshes

Bryan Klingner, Bryan Feldman, Nuttapong Chentanez, James F. O'Brien
SIGGRAPH 2006

This paper presents a method for animating fluid with unstructured tetrahedral meshes that change at each time step. Meshes that conform well to changing boundaries and ... [more]


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A Texture Synthesis Method for Liquid Animations

Adam Bargteil, Funshing Sin, Jonathan Michaels, James F. O'Brien
SIGGRAPH 2006 Tech Sketch

In this sketch we present a method for synthesizing textures on animated liquid surfaces generated by a physically based fluid simulation system. Rather than advecting ... [more]


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Simultaneous Coupling of Fluids and Deformable Bodies

Nuttapong Chentanez, Tolga Goktekin, Bryan Feldman, James F. O'Brien
SIGGRAPH 2006 Tech Sketch

We describe a method for simultaneous two-way coupling of fluid and deformable bodies. The interaction between a fluid and deformable body can create complex and interesting ... [more]


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Refolding Planar Polygons

Hayley Iben, James F. O'Brien, Erik Demaine
SoCG 2006

This paper describes an algorithm for generating a guaranteed-intersection-free interpolation sequence between any pair of compatible polygons. Our algorithm builds ... [more]


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Computational Studies of Human Motion: Tracking and Motion Synthesis

David Forsyth, Okan Arikan, Leslie Ikemoto, James F. O'Brien, Deva Ramanan
Foundations and Trends

We review methods for kinematic tracking of the human body in video. The review is part of a projected book that is intended to cross-fertilize ideas about motion representation ... [more]

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2005


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Animating Gases with Hybrid Meshes

Bryan Feldman, James F. O'Brien, Bryan Klingner
SIGGRAPH 2005

This paper presents a method for animating gases on unstructured tetrahedral meshes to efficiently model the interaction of the fluids with irregularly shaped obstacles ... [more]


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Fast and Detailed Approximate Global Illumination by Irradiance Decomposition

Okan Arikan, David A. Forsyth, James F. O'Brien
SIGGRAPH 2005

In this paper we present an approximate method for accelerated computation of the final gathering step in a global illumination algorithm. Our method operates by decomposing ... [more]


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Fluids in Deforming Meshes

Bryan Feldman, James F. O'Brien, Bryan Klingner, Tolga Goktekin
SCA 2005

This paper describes a simple modification to an Eulerian fluid simulation that permits the underlying mesh to deform independent of the simulated fluid's motion. The modification ... [more]


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Pushing People Around

Okan Arikan, David Forsyth, James F. O'Brien
SCA 2005

We present an algorithm for animating characters being pushed by an external source such as a user or a game environment. We start with a collection of motions of a real person ... [more]


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A semi-Lagrangian contouring method for fluid simulation

Adam Bargteil, Tolga Goktekin, James F. O'Brien, John A. Strain
SIGGRAPH 2005 Tech Sketch

In this sketch we present a semi-Lagrangian surface tracking method for use with fluid simulations. Our method main- tains an explicit polygonal mesh that defines the surface ... [more]


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Skeletal Parameter Estimation from Optical Motion Capture Data

Adam Kirk, James F. O'Brien, David Forsyth
CVPR 2005

In this paper we present an algorithm for automatically estimating a subject’s skeletal structure from optical mo- tion capture data. Our algorithm consists of a series ... [more]

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2004


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A Method for Animating Viscoelastic Fluids

Tolga Goktekin, Adam Bargteil, James F. O'Brien
SIGGRAPH 2004

This paper describes a technique for animating the behavior of viscoelastic fluids, such as mucus, liquid soap, pudding, toothpaste, or clay, that exhibit a combination of both ... [more]


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Skeletal Parameter Estimation from Optical Motion Capture Data

Adam Kirk, James F. O'Brien, David Forsyth
SIGGRAPH 2004 Tech Sketch

In this sketch we present an algorithm for automatically estimating a subject's skeletal structure from optical motion capture data without using any a priori skeletal ... [more]


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Refolding Planar Polygons

Hayley Iben, James F. O'Brien, Erik Demaine
SIGGRAPH 2004 Tech Sketch

This sketch describes a guaranteed technique for generating intersection-free interpolation sequences between arbitrary, non-intersecting, planar polygons. The computational ... [more]


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Interpolating and Approximating Implicit Surfaces from Polygon Soup

Chen Shen, James F. O'Brien, Jonathan Shewchuk
SIGGRAPH 2004

This paper describes a method for building interpolating or approximating implicit surfaces from polygonal data. The user can choose to generate a surface that exactly ... [more]


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Radiance Caching and Local Geometry Correction

Okan Arikan, David A. Forsyth, James F. O'Brien
SIGGRAPH 2004 Tech Sketch

We present a final gather algorithm which splits the irradiance integral into two components. One component captures the incident radiance due to distant surfaces. This ... [more]


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Spectral Surface Reconstruction from Noisy Point Clouds

Ravi Kolluri, Jonathan Shewchuk, James F. O'Brien
SGP 2004

We introduce a noise-resistant algorithm for reconstructing a watertight surface from point cloud data. It forms a Delaunay tetrahedralization, then uses a variant of ... [more]


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An Energy-Driven Approach to Linkage Unfolding

Jason Cantarella, Erik Demaine, Hayley Iben, James F. O'Brien
SoCG 2004

We present a new algorithm for unfolding planar polygonal linkages without self-intersection based on following the gradient flow of a "repulsive" energy function. This ... [more]

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2003


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Motion Synthesis from Anotations

Okan Arikan, David Forsyth, James F. O'Brien
SIGGRAPH 2003

This paper describes a framework that allows a user to synthesize human motion while retaining control of its qualitative properties. The user paints a timeline with annotations ... [more]


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Animating Suspended Particle Explosions

Bryan Feldman, James F. O'Brien, Okan Arikan
SIGGRAPH 2003

This paper describes a method for animating suspended particle explosions. Rather than modeling the numerically troublesome, and largely invisible blast wave, the method ... [more]


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Spectral Watertight Surface Reconstruction

Ravi Kolluri, Jonathan Shewchuk, James F. O'Brien
SIGGRAPH 2003 Tech Sketch

We use spectral partitioning to reconstruct a watertight surface from point cloud data. This method is particularly effective for noisy and undersampled point sets with ... [more]


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Interactive Deformation Using Modal Analysis with Constraints

Kris Hauser, Chen Shen, James F. O'Brien
Graphics Interface 2003

Modal analysis provides a powerful tool for efficiently simulating the behavior of deformable objects. This paper shows how manipulation, collision, and other constraints ... [more]

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2002


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An Energy-Driven Approach to Linkage Unfolding

Jason Cantarella, Erik Demaine, Hayley Iben, James F. O'Brien
DIMACS 2002

In this paper, we introduce a new energy-driven approach for straightening polygonal arcs and convexifying polygonal cycles without self-intersection based on following ... [more]


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Modelling with Implicit Surfaces that Interpolate

Greg Turk, James F. O'Brien
TOG

We introduce new techniques for modelling with interpolating implicit surfaces. This form of implicit surface was first used for problems of surface reconstruction and ... [more]


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Graphical Modeling and Animation of Ductile Fracture

James F. O'Brien, Adam Bargteil, Jessica Hodgins
SIGGRAPH 2002

In this paper, we describe a method for realistically animating ductile fracture in common solid materials such as plastics and metals. The effects that characterize ductile ... [more]


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Synthesizing sounds from rigid-body simulations

James F. O'Brien, Chen Shen, Christine Gatchalian
SCA 2002

This paper describes a real-time technique for generating realistic and compelling sounds that correspond to the motions of rigid objects. By numerically precomputing ... [more]


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Modal Analysis for Real-Time Viscoelastic Deformation

Chen Shen, Kris Hauser, Christine Gatchalian, James F. O'Brien
SIGGRAPH 2002 Tech Sketch

This technical sketch describes how a standard analysis technique known as modal decomposition can be used for real-time model- ing of viscoelastic deformation. While ... [more]


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Modeling the Accumulation of Wind-Driven Snow

Bryan Feldman, James F. O'Brien
SIGGRAPH 2002 Tech Sketch

This technical sketch presents a method for modeling the appearance of snow drifts formed by the accumulation of wind-blown snow near buildings and other obstacles. Our ... [more]

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2001


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Synthesizing Sounds from Physically Based Motion

James F. O'Brien, Perry R. Cook, Georg Essl
SIGGRAPH 2001

The goal of this work is to develop techniques for approximating sounds that are generated by the motions of solid objects. Our methods builds on previous work in the field ... [more]


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Image Based Rendering and Illumination Using Spherical Mosaics

Chen Shen, Heung-Yeung Shum, James F. O'Brien
SIGGRAPH 2001 Tech Sketch

The work described here extends the concentric mosaic representation developed by Shum and He to spherical mosaics that allow the viewer greater freedom of movement. Additionally ... [more]


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Implicit Surfaces that Interpolate

Greg Turk, GHuong Quynh Dinh, James F. O'Brien, Gary Yngve
Shape Modeling International 2001

Implicit surfaces are often created by summing a collection of radial basis functions. Recently, researchers have begun to create implicit surfaces that exactly interpolate ... [more]

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2000


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Animating Fracture

James F. O'Brien, Jessica Hodgins
CACM

We have developed a simulation technique that uses non-linear finite element analysis and elastic fracture mechanics to compute physically plausible motion for three-dimensional ... [more]


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Combining Active and Passive Simulations for Secondary Motion

James F. O'Brien, Victor Zordan, Jessica Hodgins
CG&A

Objects that move in response to the actions of a main character often make an important contribution to the visual richness of an animated scene. We use the term "secondary ... [more]


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Animating Explosions

Gary D. Yngve, James F. O'Brien, Jessica K. Hodgins
SIGGRAPH 2000

In this paper, we introduce techniques for animating explosions and their effects. The primary effect of an explosion is a disturbance that causes a shock wave to propagate ... [more]


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Automatic Joint Parameter Estimation from Magnetic Motion Capture Data

James F. O'Brien, Robert Bodenheimer, Gabriel Brostow, Jessica Hodgins
GI 2000

This paper describes a technique for using magnetic motion capture data to determine the joint parameters of an articulated hierarchy. This technique makes it possible ... [more]

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1999


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Graphical Modeling and Animation of Brittle Fracture

James F. O'Brien, Jessica Hodgins
SIGRAPH 1999

In this paper, we augment existing techniques for simulating flexible objects to include models for crack initiation and propagation in three-dimensional volumes. By ... [more]


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Shape Transformation Using Variational Implicit Functions

James F. O'Brien, Greg Turk
SIGGRAPH 1999

Traditionally, shape transformation using implicit functions is performed in two distinct steps: 1) creating two implicit functions, and 2) interpolating between these ... [more]


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Animating Sand, Mud, and Snow

Robert Sumner, James F. O'Brien, Jessica Hodgins
CGF

Computer animations often lack the subtle environmental changes that should occur due to the actions of the characters. Squealing car tires usually leave no skid marks ... [more]

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1998


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Perception of Human Motion with Different Geometric Models

Jessica Hodgins, James F. O'Brien, Jack Tumblin
TVCG 1998

Human figures have been animated using a variety of geometric models including stick figures, polygonal models, and NURBS-based models with muscles, flexible skin, or clothing ... [more]


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Animating Sand, Mud, and Snow

Robert Sumner, James F. O'Brien, Jessica Hodgins
GI 98

Computer animations often lack the subtle environmental changes that should occur due to the actions of the char- acters. Squealing car tires usually leave no skid marks ... [more]

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1997


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Combining Active and Passive Simulations for Secondary Motion

James F. O'Brien, Victor Zordan, Jessica Hodgins
SIGGRAPH 1997 Tech Sketch

The secondary motion of passive objects in the scene is essential for appealing and natural-looking animated characters, but because of the difficulty of controlling ... [more]


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Do Geometric Models Affect Judgments of Human Motion?

Jessica Hodgins, James F. O'Brien, Jack Tumblin
GI 97

Human figures have been animated using a wide variety of geometric models including stick figures, polygonal models, and NURBS-based models with muscles, flexible skin ... [more]

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1995


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Animating Human Athletics

Jessica Hodgins, Wayne Wooten, David Brogan, James F. O'Brien
SIGGRAPH 1995

This paper describes algorithms for the animation of men and women performing three dynamic athletic behaviors: running, bicycling, and vaulting. We animate these behaviors ... [more]


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Dynamic Simulation of Splashing Fluids

James F. O'Brien, Jessica Hodgins
Computer Animation 95

In this paper we describe a method for modeling the dynamic behavior of splashing fluids. The model simulates the behavior of a fluid when objects impact or float on its surface ... [more]