Truth in Motion: The Unprecedented Risks and Opportunities of Extended Reality Motion Data
Vivek Nair, Louis Rosenberg, James F. O'Brien, Dawn Song
IEEE S&P
Motion tracking “telemetry” data lies at the core of nearly all modern extended reality (XR) and metaverse experiences. While generally presumed innocuous, recent studies ... [more]
Deep Motion Masking for Secure, Usable, and Scalable Real-Time Anonymization of Ecological Virtual Reality Motion Data
Vivek Nair, Wenbo Guo, James F. O'Brien, Louis Rosenberg, Dawn Song
IEEE VR3D
Virtual reality (VR) and “metaverse” systems have recently seen a resurgence in interest and investment as major technology companies continue to enter the space. However ... [more]
Inferring Private Personal Attributes of Virtual Reality Users from Ecologically Valid Head and Hand Motion Data
Vivek Nair, Christian Rack, Wenbo Guo, Rui Wang, Shuixian Li, Brandon Huang, Atticus Cull, James F. O'Brien, Marc Latoschik, Louis Rosenberg, Dawn Song
IEEE VR3D
Motion tracking “telemetry” data lies at the core of nearly all mod- ern virtual reality (VR) and metaverse experiences. While generally presumed innocuous, recent studies ... [more]
Berkeley Open Extended Reality Recordings 2023 (BOXRR-23): 4.7 Million Motion Capture Recordings from 105,000 XR Users
Vivek Nair, Wenbo Guo, Rui Wang, James F. O'Brien, Louis Rosenberg, Dawn Song
IEEE VR 2024
Extended reality (XR) devices such as the Meta Quest and Apple Vision Pro have seen a recent surge in attention, with motion tracking "telemetry" data lying at the core of nearly ... [more]
Unique Identification of 50,000+ Virtual Reality Users from Head and Hand Motion Data
Vivek Nair, Wenbo Guo, Justus Mattern, Rui Wang, James F. O'Brien, Louis Rosenberg, Dawn Song
USENIX Security 23
With the recent explosive growth of interest and investment in virtual reality (VR) and the “metaverse,” public attention has rightly shifted toward the unique security and ... [more]
Exploring the Privacy Risks of Adversarial VR Game Design
Vivek Nair, Gonzalo Munilla Garrido, Dawn Song, James F. O'Brien
PoPETS 2023
Thirty study participants playtested an innocent-looking "escape room" game in virtual reality (VR). Behind the scenes, an adversarial program had accurately inferred over ... [more]
KBody: Balanced monocular whole-body estimation
Nikolaos Zioulis, James F. O'Brien
CVFAD 2023
KBody is a method for fitting a low-dimensional body model to an image. It follows a predict-and-optimize approach, relying on data-driven model estimates for the constraints ... [more]
KBody: Towards general, robust, and aligned monocular whole-body estimation
Nikolaos Zioulis, James F. O'Brien
RHOBIN 2023
KBody is a method for fitting a low-dimensional body model to an image. It follows a predict-and-optimize approach, relying on data-driven model estimates for the constraints ... [more]
Results of the 2023 Census of Beat Saber Users: Virtual Reality Gaming Population Insights and Factors Affecting Virtual Reality E-Sports Performance
Vivek Nair, Viktor Radulov, James F. O'Brien
Survey
The emergence of affordable standalone virtual reality (VR) devices has allowed VR technology to reach mass-market adoption in recent years, driven primarily by the popularity ... [more]
Monocular Facial Performance Capture Via Deep Expression Matching
Stephen Bailey, Jérémy Riviere, Morten Mikkelsen, James F. O'Brien
SCA 2022
Facial performance capture is the process of automatically animating a digital face according to a captured performance of an actor. Recent developments in this area have ... [more]
This photograph has been altered: Testing the effectiveness of image forensic labeling on news image credibility
Cuihua Shen, Mona Kasra, James F. O'Brien
Misinformation Review
Despite the ubiquity of images and videos in online news environments, much of the existing research on misinformation and its correction is solely focused on textual misinformation ... [more]
Fast and Deep Facial Deformations
Stephen Bailey, Dalton Omens, Paul Dilorenzo, James F. O'Brien
SIGGRAPH 2020
Film-quality characters typically display highly complex and expressive facial deformation. The underlying rigs used to animate the deformations of a character’s face ... [more]
Fake images: The effects of source, intermediary, and digital media literacy on contextual assessment of imag credibility online
Cuihua Shen, Mona Kasra, Wenjing Pan, Grace A. Bassett, Yining Malloch, James F. O'Brien
New Media and Society
Fake or manipulated images propagated through the Web and social media have the capacity to deceive, emotionally distress, and influence public opinions and actions. Yet ... [more]
Fast and Deep Deformation Approximations
Stephen Bailey, Dave Otte, Paul Dilorenzo, James F. O'Brien
SIGGRAPH 2018
Character rigs are procedural systems that compute the shape of an animated character for a given pose. They can be highly complex and must account for bulges, wrinkles, and ... [more]
Approximate svBRDF Estimation From Mobile Phone Video
Rachel A. Albert, Dorian Yao Chan, Dan B Goldman, James F. O'Brien
EGSR 2018
We describe a new technique for obtaining a spatially varying BRDF (svBRDF) of a flat object using printed fiducial markers and a cell phone capable of continuous flash video ... [more]
Seeing Is Believing: How People Fail to Identify Fake Images on the Web
Mona Kasra, Cuihua Shen, James F. O'Brien
CHI 2018
The growing ease with which digital images can be convincingly manipulated and widely distributed on the Internet makes viewers increasingly susceptible to visual misinformation ... [more]
Simulation of Subseismic Joint and Fault Networks Using a Heuristic Mechanical Model
Paul Gillespie, Giulio Casini, Hayley Iben, James F. O'Brien
SSRD 2017
Flow simulations of fractured and faulted reservoirs require representation of subseismic structures about which subsurface data are limited. We describe a method for ... [more]
Seeing Is Believing: Do People Fail to Identify Fake Images on the Web?
Mona Kasra, Cuihua Shen, James F. O'Brien
AoIR 2016
Images have historically been perceived as photographic proof of the depicted events. However, the growing ease with which digital images can be convincingly manipulated ... [more]
Repurposing Hand Animation for Interactive Applications
Stephen Bailey, Martin Watt, James F. O'Brien
SCA 2016
In this paper we describe a method for automatically animating interactive characters based on an existing corpus of key-framed hand-animation. The method learns separate ... [more]
Interactive Detailed Cutting of Thin Sheets
Pierre-Luc Manteaux, Wei-Lun Sun, Francois Faure, Marie-Paule Cani, James F. O'Brien
MIG 2015
In this paper we propose a method for the interactive detailed cutting of deformable thin sheets. Our method builds on the ability of frame-based simulation to solve for ... [more]
View-Dependent Adaptive Cloth Simulation with Buckling Compensation
Woojong Koh, Rahul Narain, James F. O'Brien
TVCG 2015
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]
Optimal Presentation of Imagery with Focus Cues on Multi-Plane Displays
Rahul Narain, Rachel A. Albert, Abdullah Bulbul, Gregory J. Ward, Marty Banks, James F. O'Brien
SIGGRAPH 2015
We present a technique for displaying three-dimensional imagery of general scenes with nearly correct focus cues on multi-plane displays. These displays present an additive ... [more]
Resampling Adaptive Cloth Simulations onto Fixed-Topology Meshes
George Brown, Armin Samii, James F. O'Brien, Rahul Narain
SCA 2015 Poster
We describe a method for converting an adaptively remeshed simulation of cloth into an animated mesh with fixed topology. The topology of the mesh may be specified by the ... [more]
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]
Eyeglasses-free Display: Towards Correcting Visual Aberrations with Computational Light Field Displays
Fu-Chung Huang, Gordon Wetzstein, Brian A. Barsky, Ramesh Raskar
ACM SIGGRAPH 2014
Millions of people worldwide need glasses or contact lenses to see or read properly. We introduce a computational display technology that predistorts the presented content ... [more]
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]
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]
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]
Can 3D Shape be Estimated from Focus Cues Alone?
Rachel A. Albert, Abdullah Bulbul, Rahul Narain, James F. O'Brien, Martin S. Banks
VSS 2014
Focus cues—blur and accommodation—have generally been regarded as very coarse, ordinal cues to depth. This assessment has been largely determined by the inability to display ... [more]
Correct blur and accommodation information is a reliable cue to depth ordering.
Marina Zannoli, Rachel A. Albert, Abdullah Bulbul, Rahul Narain, James F. O'Brien, Martin Banks
VSS 2014
Marshall et al. (1996) showed that blur could in principle also be used to determine depth ordering of two surfaces across an occlusion boundary from the correlation between ... [more]
The Perception of Surface Material from Disparity and Focus Cues
Martin Banks, Abdullah Bulbul, Rachel Albert, Rahul Narain, James F. O'Brien, Gregory Ward
VSS 2014
The visual properties of surfaces reveal many things including a floor's cleanliness and a car's age. These judgments of material are based on the spread of light reflected ... [more]
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]
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]
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]
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]
Type-Constrained Direct Fitting of Quadric Surfaces
James Andrews, Carlo H. Séquin
CAD 2013
We present a catalog of type-specific, direct quadric fitting methods: Given a selection of a point cloud or triangle mesh, and a desired quadric type (e.g. cone, ellipsoid, paraboloid ... [more]
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]
Generalized, Basis-Independent Kinematic Surface Fitting
James Andrews, Carlo H. Séquin
JCAD 2013
Kinematic surfaces form a general class of surfaces, including surfaces of revolution, helices, spirals, and more. Standard methods for fitting such surfaces are either specialized ... [more]
Interactive Albedo Editing in Path-Traced Volumetric Materials
Miloš Hašan, Ravi Ramamoorthi
TOG 2013
Materials such as clothing or carpets, or complex assemblies of small leaves, flower petals or mosses, do not fit well into either BRDF or BSSRDF models. Their appearance is ... [more]
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]
Correcting for Optical Aberrations using Multilayer Displays
Fu-Chung Huang, Douglas Lanman, Brian A. Barsky, Ramesh Raskar
SIGGRAPH ASIA 2012
Optical aberrations of the human eye are currently corrected using eyeglasses, contact lenses, or surgery. We describe a fourth option: modifying the composition of displayed ... [more]
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]
Interactive Inverse 3D Modeling
James Andrews, Hailin Jin, Carlo H. Séquin
CAD 2012
“Interactive Inverse 3D Modeling” is a user-guided approach to shape construction and redesign that extracts well-structured, parameterized, procedural descriptions ... [more]
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]
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]
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]
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]
Interactive Furniture Layout Using Interior Design Guidelines
Paul Merrell, Eric Schkufza, Zeyang Li, Maneesh Agrawala, Vladlen Koltun
SIGGRAPH 2011
We present an interactive furniture layout system that assists users by suggesting furniture arrangements that are based on interior design guidelines. Our system incorporates ... [more]
On the Duality of Forward and Inverse Light Transport
Manmohan Chandraker, Jiamin Bai, Tian-Tsong Ng, Ravi Ramamoorthi
PAMI 2011
Inverse light transport seeks to undo global illumination effects, such as interreflections, that pervade images of most scenes. This paper presents the theoretical and ... [more]
Interactive Extraction and Re-Design of Sweep Geometries
James Andrews, Pushkar P. Joshi, Carlo H. Séquin
CGI 2011
We introduce two interactive extraction modules that can fit the parameters of generalized sweeps to large, unstructured meshes for immediate, high-level, detail-preserving ... [more]
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]
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]
Computer generation of ribbed sculptures
James Hamlin, Carlo H. Séquin
JMA 2010
Charles Perry's monumental sculpture Solstice is analysed and its generative geometrical logic based on a twisted toroidal sweep is captured in a computer programme with ... [more]
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]
Symmetrical Embeddings of Regular Maps R5.13 and R5.6
Carlo H. Séquin
This report is a documentation of my trial-and-error design process to find a symmetrical embedding of the regular map R5.13 on a genus-5 2-manifold. It documents the non-linear ... [more]
Personalized Photograph Ranking and Selection System
Che-Hua Yeh, Yuan-Chen Ho, Brian A. Barsky, Ming Ouhyoung
ACM MM 2010
In this paper, we propose a novel personalized ranking system for amateur photographs. Although some of the features used in our system are similar to previous work, new features ... [more]
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]
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]
My Search for Symmetrical Embeddings of Regular Maps
Carlo H. Séquin
Bridges 2010
Various approaches are discussed for obtaining highly symmetrical and aesthetically pleasing space models of regular maps embedded in surfaces of genus 2 to 5. For many ... [more]
Two New Approaches to Depth of Field Post-Processing: Pyramid Spreading and Tensor Filtering
Todd J. Kosloff, Brian A. Barsky
VISIGRAPP 2010
Depth of field refers to the swath that is imaged in sharp focus through an optics system, such as a camera lens. Control over depth of field is an important artistic tool, which ... [more]
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]
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]
An intuitive explanation of third-order surface behavior
Pushkar P. Joshi, Carlo H. Séquin
CAGD
We present a novel parameterization-independent exposition of the third-order geometric behavior of a surface point. Unlike existing algebraic expositions, our work ... [more]
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]
Simulating Gaseous Fluids with Low and High Speeds
Yue Gao, Chen-Feng Li, Shi-Min Hu, Brian A. Barsky
Pacific Graphics 09
Gaseous fluids may move slowly, as smoke does, or at high speed, such as occurs with explosions. High-speed gas flow is always accompanied by low-speed gas flow, which produces ... [more]
Three Techniques for Rendering Generalized Depth of Field Effects
Todd J. Kosloff, Brian A. Barsky
MI 09
Depth of field refers to the swath that is imaged in sufficient focus through an optics system, such as a camera lens. Control over depth of field is an important artistic tool ... [more]
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]
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]
3D Clothing Fitting Based on the Geometric Feature Matching
Zhong Li, Xiaogang Jin, Brian Barsky, Jun Liu
CAD/Graphics 2009
The 3D clothing fitting on a body model is an important research topic in the garment computer aided design (GCAD). During the fitting process, the match between the clothing ... [more]
Tubular Sculptures
Carlo H. Séquin
Bridges 2009
This paper reviews ways in which many artists have constructed large sculptures from tubular elements, ranging from single cylinders to toroidal or knotted structures ... [more]
Visualizing High-Order Surface Geometry
Pushkar P. Joshi, Carlo H. Séquin
CAD&A 2009
We have derived parameters that describe the higher-order geometric behavior of smooth surfaces. Our parameters are similar in spirit to the principal directions and ... [more]
An Effective Third-order Local Fitting Patch and Its Application
Zhong Li, Brian Barsky, Xiaogang Jin
SMI 2009
In this paper, we extend Razdan and Bae’s second-order local fitting method [11] to construct an effective third-order fitting patch. Compared to other estimation algorithms ... [more]
Ribbed Surfaces for Art, Architecture, and Visualization
James Hamlin, Carlo H. Séquin
CAD&A 2009
Sequences of parameterized Hermite curves following with their endpoints along two guide rails are used to create "transparent" surfaces and tubular sculptures. This parameterized ... [more]
CAD Tools for Creating Space-filling 3D Escher Tiles
Mark Howison, Carlo H. Séquin
CAD&A 2009
We discuss the design and implementation of CAD tools for creating decorative solids that tile 3-space in a regular, isohedral manner. Starting with the simplest case of ... [more]
Interpolating Splines: Which is the fairest of them all?
Raph Levien, Carlo H. Séquin
CAD&A 2009
Interpolating splines are a basic primitive for designing planar curves. There is a wide diversity in the literature but no consensus on a "best" spline, or even criteria for ... [more]
Depth of Field Postprocessing For Layered Scenes Using Constant-Time Rectangle Spreading
Todd Kosloff, Michael W. Tao, Brian Barsky
GI 2009
Control over what is in focus and what is not in focus in an image is an important artistic tool. The range of depth in a 3D scene that is imaged in sufficient focus through an optics ... [more]
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]
Intricate Isohedral Tilings of 3D Euclidean Space
Carlo H. Séquin
Bridges 2008
Various methods to create intricate tilings of 3D space are presented. They include modulated extrusions of 2D Escher tilings, free-form deformations of the fundamental ... [more]
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]
A Precomputed Polynomial Representation for Interactive BRDF Editing with Global Illumination
Aner Ben-Artzi, Kevin Egan, Kevin Egan, Frédo Durand, Ravi Ramamoorthi
TOG
The ability to interactively edit BRDFs in their final placement within a computer graphics scene is vital to making informed choices for material properties. We significantly ... [more]
Geometrically exact dynamic splines
Adrien Theetten, Laurent Grisoni, Claude Andriot, Brian Barsky
Computer-Aided Design 2008
We propose a complete model handling the physical simulation of deformable 1D objects. We formulate continuous expressions for stretching, bending and twisting energies ... [more]
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]
An Algorithm for Rendering Generalized Depth of Field Effects Based on Simulated Heat Diffusion
Todd Kosloff, Brian Barsky
ICCSA 2007
Depth of field refers to the swath through a 3Dscene that is imaged in acceptable focus through an optics system, such as a camera lens. Control over depth of field is an important ... [more]
Symmetric Embedding of Locally Regular Hyperbolic Tilings
Carlo H. Séquin
Bridges 2007
Various methods to create intricate tilings of 3D space are presented. They include modulated extrusions of 2D Escher tilings, free-form deformations of the fundamental ... [more]
Computer-Aided Design and Realization of Geometrical Sculptures
Carlo H. Séquin
The use of computer-aided design tools in the conception and realization of large-scale geometrical bronze sculptures is described. An inspirational piece of sculpture ... [more]
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]
Hyper-Seeing the Regular Hendeca-choron
Carlo H. Séquin
ISAMA 2007
The hendecachoron is an abstract 4-dimensional polytope composed of eleven cells in the form of hemi-icosahedra. This paper tries to foster an understanding of this intriguing ... [more]
Design and Implementation of Pax Mundi II
Carlo H. Séquin
On January 18, 2007 a ten foot tall bronze sculpture Pax Mundi II was installed in the courtyard of the H&R Block headquarters in Kansas City. This paper describes the computer-aided ... [more]
4D compression and relighting with high-resolution light transport matrices
Ewen Cheslack-Postava, Nolan Goodnight, Ren Ng, Ravi Ramamoorthi, Greg Humphreys
I3D 2007
This paper presents a method for efficient compression and relighting with high-resolution, precomputed light transport matrices. We accomplish this using a 4D wavelet ... [more]
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]
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]
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]
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]
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]
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]
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]
Acquiring Scattering Properties of Participating Media by Dilution
Srinivasa G. Narasimhan, Mohit Gupta, Craig Donner , Ravi Ramamoorthi, Shree Nayar, Henrik Wann Jensen
SIGGRAPH 2006
The visual world around us displays a rich set of volumetric effects due to participating media. The appearance of these media is governed by several physical properties ... [more]
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]
Patterns on the Genus-3 Klein Quartic
Carlo H. Séquin
Bridges 2006
Projections of Klein's quartic surface of genus 3 into 3D space are used as canvases on which we present regular tessellations, Escher tilings, knot- and graph-embedding ... [more]
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]
Extensions for 3D Graphics Rendering Engine used for Direct Tessellation of Spline Surfaces
Adrien Sfarti, Brian Barsky, Todd Kosloff, Egon Pasztor, Alex Kozlowski, Eric Roman, Alex Perelman
ICCS 2006
In current 3D graphics architectures, the bus between the triangle server and the rendering engine GPU is clogged with triangle vertices and their many attributes (normal ... [more]
New 3D Graphics Rendering Engine Architecture for Direct Tessellation of Spline Surfaces
Adrien Sfarti, Brian Barsky, Todd Kosloff, Egon Pasztor, Alex Kozlowski, Eric Roman, Alex Perelman
3IA 2006
In current 3D graphics architectures, the bus between the triangle server and the rendering engine GPU is clogged with triangle vertices and their many attributes (normal ... [more]
Human Vision Based Detection of Non-Uniform Brightness on LCD Panels
Jee Hong Kim, Brian Barsky
MVAII 2004
We propose a method to detect defects due to spatially non-uniform brightness on LCD panels by using a machine vision technique. The detection method is based on human vision ... [more]
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]
Interactive Procedural Computer-Aided Design
Carlo H. Séquin
CAD/Graphics 2005
The typical engineering design process can be decomposed into several phases: creative exploration of ideas, testing soundness of proposed concepts, refining concepts ... [more]
Semi-Automated Ultrasound Interpretation System Using Anatomical Knowledge Representation
Michael S. Downes, Brian Barsky
VC 2005
Interpreting ultrasound data presents a significant challenge to medical personnel, which limits the clinical applications of the technology. We have addressed this ... [more]
Elimination of Artifacts Due to Occlusion and Discretization Problems in Image Space Blurring Techniques
Brian Barsky, Michael Tobias, Derrick P. Chu, Daniel R. Horn
GM 2005
Traditional computer graphics methods render images that appear sharp at all depths. Adding blur can add realism to a scene, provide a sense of scale, and draw a viewerÕs attention ... [more]
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]
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]
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]
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]
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]
Symmetrical Hamiltonian Manifolds on Regular 3D and 4d Polytopes
Carlo H. Séquin
Coxeter Day 2005
Hamiltonian cycles on the edge graphs of the regular polytopes in three and four dimensions are investigated with the primary goal of finding complete multi-colored coverages ... [more]
Splitting Tori, Knots, and Moebius Bands
Carlo H. Séquin
Bridges 2005
A study of sculptures and puzzles resulting from splitting lengthwise, tori, Moebius bands, various knots and graphs, illustrated with many models made on rapid prototyping ... [more]
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]
New 3D Graphics Rendering Engine Architecture for Direct Tessellation of Spline Surfaces
Adrien Sfarti, Brian Barsky, Todd Kosloff, Egon Pasztor, Alex Kozlowski, Eric Roman, Alex Perelman
ICCS 2005
In current 3D graphics architectures, the bus between the triangle server and the rendering engine GPU is clogged with triangle vertices and their many attributes (normal ... [more]
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]
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]
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]
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]
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]
An Opponent Process Approach to Modeling the Blue Shift of the Human Color Vision System
Brian Barsky, Todd Kosloff, Steven D. Upstill
APGV 2004
Low light level affects human visual perception in various ways. Visual acuity is reduced and scenes appear bluer, darker, less saturated, and with reduced contrast. We confine ... [more]
Rendering Skewed Plane of Sharp Focus and Associated Depth of Field
Brian Barsky, Egon Pasztor
SIGGRAPH 2004
Depth of field is the region of a scene that is in focus in an image. This is measured relative to a plane-of-sharp focus. When using a physical camera, this plane is perpendicular ... [more]
Vision-Realistic Rendering: Simulation of the Scanned Foveal Image from Wavefront Data of Human Subjects
Brian Barsky
APGV 2004
We introduce the concept of vision-realistic rendering – the com- puter generation of synthetic images that incorporate the charac- teristics of a particular individual ... [more]
Triple Product Wavelet Integrals for All-Frequency Relighting
Ren Ng, Ravi Ramamoorthi, Pat Hanrahan
SIGGRAPH 2004
This paper focuses on efficient rendering based on pre-computed light transport, with realistic materials and shadows under all-frequency direct lighting such as environment ... [more]
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]
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]
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]
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]
All-Frequncy Shadows Using Non-linear Wavelet Lighting Approximation
Ren Ng, Ravi Ramamoorthi, Pat Hanrahan
SIGGRAPH 2003
We present a method, based on pre-computed light transport, for real-time rendering of objects under all-frequency, time-varying illumination represented as a high-resolution ... [more]
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]
Investigating Occlusion and Discretization Problems in Image Space Blurring Techniques
Brian Barsky, Michael J. Tobias, Daniel R. Horn, Derrick P. Chu
VVG 2003
Traditional computer graphics methods render images that appear sharp at all depths. Adding blur can add realism to a scene, provide a sense of scale, and draw a viewer’s attention ... [more]
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]
Camera Models and Optical Systems Used in Computer Graphics: Part I, Object Based Techniques
Brian Barsky, Daniel R. Horn, Stanley A. Klein, Jeffrey A. Pang, Meng Yu
ICCSA 03
Images rendered with traditional computer graphics techniques, such as scanline rendering and ray tracing, appear focused at all depths. However, there are advantages to ... [more]
Camera Models and Optical Systems Used in Computer Graphics: Part II, Image Based Techniques
Brian Barsky, Daniel R. Horn, Stanley A. Klein, Jeffrey A. Pang, Meng Yu
ICCSA 03
In our companion paper [5], we described the optics underlying camera models that have been used in computer graphics, and presented object space techniques for rendering ... [more]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]