https://objf.ai/publications.html Academic publications by James F. O'Brien. Sat, 11 Jul 2026 03:02:00 GMT https://objf.ai/papers/Kim-RSG-2026-05/ https://objf.ai/papers/Kim-RSG-2026-05/ Fri, 01 May 2026 00:00:00 GMT We present the first motion generation system for playtesting virtual reality (VR) games. Our player model generates VR headset and handheld controller movements from in-game object arrangements, guided by style exemplars and aligned to maximize simulated. https://objf.ai/papers/Nair-EDD-2024-06/ https://objf.ai/papers/Nair-EDD-2024-06/ Sat, 01 Jun 2024 00:00:00 GMT The use of virtual and augmented reality devices is increasing, but these sensor-rich devices pose risks to privacy. The ability to track a user’s motion and infer the identity or characteristics of the user poses a privacy risk that has received significant. https://objf.ai/papers/Miller-EDD-2024-06/ https://objf.ai/papers/Miller-EDD-2024-06/ Sat, 01 Jun 2024 00:00:00 GMT Social virtual reality is an emerging medium of communication. In this medium, a user's avatar (virtual representation) is controlled by the tracked motion of the user's headset and hand controllers. This tracked motion is a rich data stream that can leak. https://objf.ai/papers/Nair-IPP-2024-03/ https://objf.ai/papers/Nair-IPP-2024-03/ Fri, 01 Mar 2024 00:00:00 GMT Motion tracking “telemetry” data lies at the core of nearly all modern virtual reality (VR) and metaverse experiences. While generally presumed innocuous, recent studies have demonstrated that motion data actually has the potential to uniquely identify VR. https://objf.ai/papers/Nair-DMM-2024-03/ https://objf.ai/papers/Nair-DMM-2024-03/ Fri, 01 Mar 2024 00:00:00 GMT 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, recent studies have demonstrated that the motion tracking “telemetry” data used by. https://objf.ai/papers/Nair-BOX-2024-03/ https://objf.ai/papers/Nair-BOX-2024-03/ Fri, 01 Mar 2024 00:00:00 GMT 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 all XR and metaverse experiences. Researchers are just beginning to understand. https://objf.ai/papers/Nair-TIM-2024-05/ https://objf.ai/papers/Nair-TIM-2024-05/ Mon, 01 Jan 2024 00:00:00 GMT Motion tracking “telemetry” data lies at the core of nearly all modern extended reality (XR) and metaverse experiences. While generally presumed innocuous, recent studies have demonstrated that motion data actually has the potential to profile and. https://objf.ai/papers/Nair-UI5-2023-08/ https://objf.ai/papers/Nair-UI5-2023-08/ Tue, 01 Aug 2023 00:00:00 GMT 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 privacy threats that these platforms may pose. While it has long been known that. https://objf.ai/papers/Nair-EPR-2023-07/ https://objf.ai/papers/Nair-EPR-2023-07/ Sat, 01 Jul 2023 00:00:00 GMT Thirty study participants playtested an innocent-looking "escape room" game in virtual reality (VR). Behind the scenes, an adversarial program had accurately inferred over 25 personal data attributes, from anthropometrics like height and wingspan to. https://objf.ai/papers/Zioulis-KBT-2023-06/ https://objf.ai/papers/Zioulis-KBT-2023-06/ Thu, 01 Jun 2023 00:00:00 GMT 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 that will be used to solve for the body's parameters. Acknowledging the importance. https://objf.ai/papers/Zioulis-KBB-2023-06/ https://objf.ai/papers/Zioulis-KBB-2023-06/ Thu, 01 Jun 2023 00:00:00 GMT 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 that will be used to solve for the body's parameters. Compared to other approaches. https://objf.ai/papers/Nair-ROT-2023-05/ https://objf.ai/papers/Nair-ROT-2023-05/ Mon, 01 May 2023 00:00:00 GMT 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 of VR gaming applications such as Beat Saber. However, despite being the. https://objf.ai/papers/Bailey-MFP-2022-09/ https://objf.ai/papers/Bailey-MFP-2022-09/ Thu, 01 Sep 2022 00:00:00 GMT 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 focused on high-quality results using expensive head-scanning equipment and camera. https://objf.ai/papers/Shen-TPA-2021-05/ https://objf.ai/papers/Shen-TPA-2021-05/ Sat, 01 May 2021 00:00:00 GMT 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, and little is known about how ordinary users evaluate fake or manipulated. https://objf.ai/papers/Bailey-FDF-2020-07/ https://objf.ai/papers/Bailey-FDF-2020-07/ Sat, 01 Aug 2020 00:00:00 GMT Film-quality characters typically display highly complex and expressive facial deformation. The underlying rigs used to animate the deformations of a character’s face are often computationally expensive, requiring high-end hardware to deform the mesh at. https://objf.ai/papers/Shen-FIT-2019-02/ https://objf.ai/papers/Shen-FIT-2019-02/ Fri, 01 Feb 2019 00:00:00 GMT 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 few studies have examined how individuals evaluate the authenticity of images that. https://objf.ai/papers/Bailey-FDD-2018-08/ https://objf.ai/papers/Bailey-FDD-2018-08/ Wed, 01 Aug 2018 00:00:00 GMT 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 other aspects of a character's appearance. When comparing film-quality character. https://objf.ai/papers/Albert-ASV-2018-06/ https://objf.ai/papers/Albert-ASV-2018-06/ Fri, 01 Jun 2018 00:00:00 GMT 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. Our homography-based video frame alignment method does not require the fiducial. https://objf.ai/papers/Kasra-SIB-2018-04/ https://objf.ai/papers/Kasra-SIB-2018-04/ Sun, 01 Apr 2018 00:00:00 GMT The growing ease with which digital images can be convincingly manipulated and widely distributed on the Internet makes viewers increasingly susceptible to visual misinformation and deception. In situations where ill-intentioned individuals seek to. https://objf.ai/papers/Gillespie-SSJ-2017-04/ https://objf.ai/papers/Gillespie-SSJ-2017-04/ Sat, 01 Apr 2017 00:00:00 GMT Flow simulations of fractured and faulted reservoirs require representation of subseismic structures about which subsurface data are limited. We describe a method for simulating fracture growth that is mechanically based but heuristic, allowing for realistic. https://objf.ai/papers/Kasra-SIB-2016-10/ https://objf.ai/papers/Kasra-SIB-2016-10/ Sat, 01 Oct 2016 00:00:00 GMT Images have historically been perceived as photographic proof of the depicted events. However, the growing ease with which digital images can be convincingly manipulated and then widely distributed on the Internet makes viewers increasingly susceptible to. https://objf.ai/papers/Bailey-RHA-2016-07/ https://objf.ai/papers/Bailey-RHA-2016-07/ Fri, 01 Jul 2016 00:00:00 GMT 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 low-dimensional embeddings for subsets of the hand-animation corresponding to different. https://objf.ai/papers/Manteaux-IDC-2015-11/ https://objf.ai/papers/Manteaux-IDC-2015-11/ Sun, 01 Nov 2015 00:00:00 GMT 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 dynamics using very few control frames while embedding highly detailed geometry - here. https://objf.ai/papers/Koh-VDA-2015-10/ https://objf.ai/papers/Koh-VDA-2015-10/ Thu, 01 Oct 2015 00:00:00 GMT This paper describes a method for view-dependent cloth simulation using dynamically adaptive mesh refinement and coarsening. Given a prescribed camera motion, the method adjusts the criteria controlling refinement to account for visibility and apparent size. https://objf.ai/papers/Narain-OPI-2015-08/ https://objf.ai/papers/Narain-OPI-2015-08/ Sat, 01 Aug 2015 00:00:00 GMT 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 combination of images at a discrete set of optical distances, allowing the viewer to. https://objf.ai/papers/Brown-RAC-2015-08/ https://objf.ai/papers/Brown-RAC-2015-08/ Sat, 01 Aug 2015 00:00:00 GMT 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 user or computed automatically. In the latter case, we present a method for computing. https://objf.ai/papers/Kee-EPM-2014-09/ https://objf.ai/papers/Kee-EPM-2014-09/ Mon, 01 Sep 2014 00:00:00 GMT 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 constraints on the projected location of a distant point light source. The. https://objf.ai/papers/Zannoli-CBA-2014-05/ https://objf.ai/papers/Zannoli-CBA-2014-05/ Fri, 01 Aug 2014 00:00:00 GMT 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 the boundary’s blur and the blur of the two surfaces. They tested this. https://objf.ai/papers/Banks-TPO-2014-05/ https://objf.ai/papers/Banks-TPO-2014-05/ Fri, 01 Aug 2014 00:00:00 GMT 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 from a surface. The bidirectional reflectance distribution function (BRDF) quantifies. https://objf.ai/papers/Albert-C3S-2014-05/ https://objf.ai/papers/Albert-C3S-2014-05/ Fri, 01 Aug 2014 00:00:00 GMT 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 these cues correctly with conventional displays. For example, when a 3D shape is. https://objf.ai/papers/Stanton-SRG-2014-07/ https://objf.ai/papers/Stanton-SRG-2014-07/ Tue, 01 Jul 2014 00:00:00 GMT 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 in practical applications, such as gameplay, users explore only a vanishingly small. https://objf.ai/papers/Pfaff-ATC-2014-07/ https://objf.ai/papers/Pfaff-ATC-2014-07/ Tue, 01 Jul 2014 00:00:00 GMT This paper presents a method for adaptive fracture propagation in thin sheets. A high-quality triangle mesh is dynamically restructured to adaptively maintain detail wherever it is required by the simulation. These requirements include refining where cracks. https://objf.ai/papers/Koh-VDA-2014-07/ https://objf.ai/papers/Koh-VDA-2014-07/ Tue, 01 Jul 2014 00:00:00 GMT This paper describes a method for view-dependent cloth simulation using dynamically adaptive mesh refinement and coarsening. Given a prescribed camera motion, the method adjusts the criteria controlling refinement to account for visibility and apparent size. https://objf.ai/papers/Liu-FSM-2013-11/ https://objf.ai/papers/Liu-FSM-2013-11/ Fri, 01 Nov 2013 00:00:00 GMT 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 linear (Hookean) springs. We express the widely used implicit Euler method as an. https://objf.ai/papers/Kee-EPM-2013-09/ https://objf.ai/papers/Kee-EPM-2013-09/ Sun, 01 Sep 2013 00:00:00 GMT We describe a geometric technique to detect physically inconsistent arrangements of shadows in an image. This technique combines multiple constraints from cast and attached shadows to constrain the projected location of a point light source. The consistency. https://objf.ai/papers/Narain-FCA-2013-07/ https://objf.ai/papers/Narain-FCA-2013-07/ Mon, 01 Jul 2013 00:00:00 GMT 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 of adaptive mesh refinement to dynamically align mesh edges with folds and. https://objf.ai/papers/Kim-NEP-2013-07/ https://objf.ai/papers/Kim-NEP-2013-07/ Mon, 01 Jul 2013 00:00:00 GMT 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 space. In this paper, we challenge that assumption by using several thousand CPU-hours to. https://objf.ai/papers/Clausen-SLS-2013-04/ https://objf.ai/papers/Clausen-SLS-2013-04/ Mon, 01 Apr 2013 00:00:00 GMT 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 a high-quality tetrahedral discretization even as the mesh is advected by fluid flow. https://objf.ai/papers/Narain-AAR-2012-11/ https://objf.ai/papers/Narain-AAR-2012-11/ Thu, 01 Nov 2012 00:00:00 GMT 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 of the simulated cloth. Our technique produces anisotropic meshes that adapt to surface. https://objf.ai/papers/Hecht-USC-2012-08/ https://objf.ai/papers/Hecht-USC-2012-08/ Mon, 01 Oct 2012 00:00:00 GMT We present warp-canceling corotation, a nonlinear finite element formulation for elastodynamic simulation that achieves fast performance by making only partial or delayed changes to the simulation’s linearized system matrices. Coupled with an algorithm for. https://objf.ai/papers/Conotter-EDF-2012-02/ https://objf.ai/papers/Conotter-EDF-2012-02/ Wed, 01 Feb 2012 00:00:00 GMT We describe a geometric technique to detect physically implausible trajectories of objects in video sequences. This technique explicitly models the three-dimensional ballistic motion of objects in free-flight and the two-dimensional projection of the. https://objf.ai/papers/Obrien-EPM-2012-01/ https://objf.ai/papers/Obrien-EPM-2012-01/ Sun, 01 Jan 2012 00:00:00 GMT The advent of sophisticated photo editing software has made it increasingly easier to manipulate digital images. Often visual inspection cannot definitively distinguish the resulting forgeries from authentic photographs. In response, forensic techniques have. https://objf.ai/papers/Wang-DDE-2011-08/ https://objf.ai/papers/Wang-DDE-2011-08/ Fri, 01 Jul 2011 00:00:00 GMT Cloth often has complicated nonlinear, anisotropic elastic behavior due to its woven pattern and fiber properties. However, most current cloth simulation techniques simply use linear and isotropic elastic models with manually selected stiffness parameters. https://objf.ai/papers/Kirk-PBT-2011-08/ https://objf.ai/papers/Kirk-PBT-2011-08/ Fri, 01 Jul 2011 00:00:00 GMT 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 color shift occurs as the eye transitions from photopic, cone-mediated vision in. https://objf.ai/papers/Javdani-MPD-2011-05/ https://objf.ai/papers/Javdani-MPD-2011-05/ Sun, 01 May 2011 00:00:00 GMT 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, perception, and manipulation of such objects. An important application of these tasks. https://objf.ai/papers/CusumanoTowner-BCD-2011-05/ https://objf.ai/papers/CusumanoTowner-BCD-2011-05/ Sun, 01 May 2011 00:00:00 GMT 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 model (HMM) for estimating the identity of the article and tracking the article's. https://objf.ai/papers/Wang-MRI-2010-12/ https://objf.ai/papers/Wang-MRI-2010-12/ Wed, 01 Dec 2010 00:00:00 GMT 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 or individual strain components, this method acts on the strain tensors in a. https://objf.ai/papers/Wicke-DLR-2010-07/ https://objf.ai/papers/Wicke-DLR-2010-07/ Thu, 01 Jul 2010 00:00:00 GMT 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 reshaped by plastic flow, fracture, or large elastic deformations. To. https://objf.ai/papers/Wang-EBW-2010-07/ https://objf.ai/papers/Wang-EBW-2010-07/ Thu, 01 Jul 2010 00:00:00 GMT 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 dresses or capes, these types of garments involve nearly continuous collision. https://objf.ai/papers/Held-UBA-2010-03/ https://objf.ai/papers/Held-UBA-2010-03/ Mon, 01 Mar 2010 00:00:00 GMT 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 model explains how the pattern of blur in an image together with relative depth cues. https://objf.ai/papers/Chentanez-SNI-2010-04/ https://objf.ai/papers/Chentanez-SNI-2010-04/ Fri, 01 Jan 2010 00:00:00 GMT Realistic modeling of needle insertion during brachytherapy can be used for training and in automated planning to reduce errors between intended and actual placement of the needle tip. We have developed a three-dimensional tetrahedral finite element. https://objf.ai/papers/Parker-RTD-2009-08/ https://objf.ai/papers/Parker-RTD-2009-08/ Sat, 01 Aug 2009 00:00:00 GMT 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 tetrahedral finite element method, this system has been constructed from. https://objf.ai/papers/Chentanez-ISN-2009-08/ https://objf.ai/papers/Chentanez-ISN-2009-08/ Sat, 01 Aug 2009 00:00:00 GMT We present algorithms for simulating and visualizing the insertion and steering of needles through deformable tissues for surgical training and planning. Needle insertion is an essential component of many clinical procedures such as biopsies, injections. https://objf.ai/papers/Iben-RPP-2009-04/ https://objf.ai/papers/Iben-RPP-2009-04/ Wed, 01 Apr 2009 00:00:00 GMT This paper describes an algorithm for generating a guaranteed intersection-free interpolation sequence between any pair of compatible polygons. Our algorithm builds on prior results from linkage unfolding, and if desired it can ensure that every edge length. https://objf.ai/papers/Iben-GSC-2009-11/ https://objf.ai/papers/Iben-GSC-2009-11/ Thu, 01 Jan 2009 00:00:00 GMT 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 based methods. Our algorithm generates cracks from a stress field defined. https://objf.ai/papers/Held-MBT-2008-05/ https://objf.ai/papers/Held-MBT-2008-05/ Thu, 01 May 2008 00:00:00 GMT Blur is commonly considered a weak distance cue, but photographic techniques that manipulate blur cause significant and compelling changes in the perceived distance and size of objects. One such technique is "tilt-shift miniaturization," in which a camera's. https://objf.ai/papers/Chentanez-LSL-2007-08/ https://objf.ai/papers/Chentanez-LSL-2007-08/ Wed, 01 Aug 2007 00:00:00 GMT 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 with a boundary-conforming tetrahedral mesh that grades from fine resolution near the. https://objf.ai/papers/Eden-AMF-2007-05/ https://objf.ai/papers/Eden-AMF-2007-05/ Tue, 01 May 2007 00:00:00 GMT 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 Mermaid, and Bambi . We take as input a liquid surface obtained from a. https://objf.ai/papers/Alterovitz-MPH-2006-11/ https://objf.ai/papers/Alterovitz-MPH-2006-11/ Wed, 01 Nov 2006 00:00:00 GMT 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 implanted in the prostate. Clinicians must set dwell times for the source inside the. https://objf.ai/papers/Iben-GSC-2006-09/ https://objf.ai/papers/Iben-GSC-2006-09/ Fri, 01 Sep 2006 00:00:00 GMT 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 based methods. Our algorithm generates cracks from a stress field defined. https://objf.ai/papers/Bargteil-ATS-2006-09/ https://objf.ai/papers/Bargteil-ATS-2006-09/ Fri, 01 Sep 2006 00:00:00 GMT 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 texture coordinates on the surface, we synthesize a new texture for every frame. We. https://objf.ai/papers/Klingner-FAD-2006-08/ https://objf.ai/papers/Klingner-FAD-2006-08/ Tue, 01 Aug 2006 00:00:00 GMT 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 that focus computation in the visually important parts of the domain can be generated. https://objf.ai/papers/Chentanez-SCP-2006-08/ https://objf.ai/papers/Chentanez-SCP-2006-08/ Tue, 01 Aug 2006 00:00:00 GMT 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 where a linear pressure projection on the fluid velocities enforces mass. https://objf.ai/papers/Chentanez-SCP-2006-07/ https://objf.ai/papers/Chentanez-SCP-2006-07/ Sat, 01 Jul 2006 00:00:00 GMT 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 motion that would be difficult to convincingly animate by hand. https://objf.ai/papers/Bargteil-ATS-2006-08/ https://objf.ai/papers/Bargteil-ATS-2006-08/ Sat, 01 Jul 2006 00:00:00 GMT 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 texture coordinates on the surface, we synthesize a new texture for every frame. We. https://objf.ai/papers/Iben-RPP-2006-06/ https://objf.ai/papers/Iben-RPP-2006-06/ Thu, 01 Jun 2006 00:00:00 GMT This paper describes an algorithm for generating a guaranteed-intersection-free interpolation sequence between any pair of compatible polygons. Our algorithm builds on prior results from linkage unfolding, and if desired it can ensure that every edge length. https://objf.ai/papers/Forsyth-CSH-2006-00/ https://objf.ai/papers/Forsyth-CSH-2006-00/ Sun, 01 Jan 2006 00:00:00 GMT 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 between the animation and computer vision communities. The review confines. https://objf.ai/papers/Bargteil-ASL-2006-XX/ https://objf.ai/papers/Bargteil-ASL-2006-XX/ Sun, 01 Jan 2006 00:00:00 GMT 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, and an octree data structure that provides both a spatial index for the mesh and a. https://objf.ai/papers/Feldman-AGH-2005-08/ https://objf.ai/papers/Feldman-AGH-2005-08/ Mon, 01 Aug 2005 00:00:00 GMT This paper presents a method for animating gases on unstructured tetrahedral meshes to efficiently model the interaction of the fluids with irregularly shaped obstacles. Because our discretization scheme parallels that of the standard staggered grid mesh we. https://objf.ai/papers/Feldman-FDM-2005-07/ https://objf.ai/papers/Feldman-FDM-2005-07/ Fri, 01 Jul 2005 00:00:00 GMT 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 consists of a straightforward adaptation of the commonly used semi-Lagrangian. https://objf.ai/papers/Arikan-PPA-2005-07/ https://objf.ai/papers/Arikan-PPA-2005-07/ Fri, 01 Jul 2005 00:00:00 GMT 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 responding to being pushed. When a character is pushed, we synthesize new motions. https://objf.ai/papers/Arikan-FAD-2005-07/ https://objf.ai/papers/Arikan-FAD-2005-07/ Fri, 01 Jul 2005 00:00:00 GMT 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 the radiance field close to surfaces into separate far- and near-field components. https://objf.ai/papers/Kirk-SPE-2005-06/ https://objf.ai/papers/Kirk-SPE-2005-06/ Wed, 01 Jun 2005 00:00:00 GMT 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 of steps that cluster markers into segment groups, determine the topological connectivity. https://objf.ai/papers/Bargteil-ASL-2005-07/ https://objf.ai/papers/Bargteil-ASL-2005-07/ Sat, 01 Jan 2005 00:00:00 GMT 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, and an octree data structure that provides both a spatial index for the mesh and. https://objf.ai/papers/Shen-IAI-2004-08/ https://objf.ai/papers/Shen-IAI-2004-08/ Sun, 01 Aug 2004 00:00:00 GMT 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 interpolates the polygons, or a surface that approximates the input by smoothing away. https://objf.ai/papers/Kirk-SPE-2004-08/ https://objf.ai/papers/Kirk-SPE-2004-08/ Sun, 01 Aug 2004 00:00:00 GMT 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 model. Our algorithm consists of a series of four steps that cluster markers into groups. https://objf.ai/papers/Iben-RPP-2004-08/ https://objf.ai/papers/Iben-RPP-2004-08/ Sun, 01 Aug 2004 00:00:00 GMT This sketch describes a guaranteed technique for generating intersection-free interpolation sequences between arbitrary, non-intersecting, planar polygons. The computational machinery that ensures against self intersection guides a user-supplied distance. https://objf.ai/papers/Arikan-RCL-2004-08/ https://objf.ai/papers/Arikan-RCL-2004-08/ Sun, 01 Aug 2004 00:00:00 GMT 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 incident radiance due to far field illumination is represented as a spatially varying. https://objf.ai/papers/Kolluri-SSR-2004-07/ https://objf.ai/papers/Kolluri-SSR-2004-07/ Thu, 01 Jul 2004 00:00:00 GMT 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 spectral graph partitioning to decide whether each tetrahedron is inside or outside the. https://objf.ai/papers/Cantarella-AED-2004-06/ https://objf.ai/papers/Cantarella-AED-2004-06/ Tue, 01 Jun 2004 00:00:00 GMT 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 algorithm has several advantages over previous methods. (1) The output motion is. https://objf.ai/papers/Goktekin-AMF-2004-08/ https://objf.ai/papers/Goktekin-AMF-2004-08/ Thu, 01 Jan 2004 00:00:00 GMT 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 fluid and solid characteristics. The technique builds upon prior Eulerian methods. https://objf.ai/papers/Feldman-ASP-2003-08/ https://objf.ai/papers/Feldman-ASP-2003-08/ Fri, 01 Aug 2003 00:00:00 GMT This paper describes a method for animating suspended particle explosions. Rather than modeling the numerically troublesome, and largely invisible blast wave, the method uses a relatively stable incompressible fluid model to account for the motion of air and. https://objf.ai/papers/Arikan-MSF-2003-08/ https://objf.ai/papers/Arikan-MSF-2003-08/ Fri, 01 Aug 2003 00:00:00 GMT 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 --- like walk, run or jump --- from a vocabulary which is freely chosen by the. https://objf.ai/papers/Kolluri-SWS-2003-07/ https://objf.ai/papers/Kolluri-SWS-2003-07/ Tue, 01 Jul 2003 00:00:00 GMT 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 outliers, because decisions about the reconstructed surface are based on a global view of. https://objf.ai/papers/Hauser-IDU-2003-06/ https://objf.ai/papers/Hauser-IDU-2003-06/ Sun, 01 Jun 2003 00:00:00 GMT Modal analysis provides a powerful tool for efficiently simulating the behavior of deformable objects. This paper shows how manipulation, collision, and other constraints may be implemented easily within a modal framework. Results are presented for several. https://objf.ai/papers/Cantarella-AED-2002-11/ https://objf.ai/papers/Cantarella-AED-2002-11/ Fri, 01 Nov 2002 00:00:00 GMT In this paper, we introduce a new energy-driven approach for straightening polygonal arcs and convexifying polygonal cycles without self-intersection based on following the gradient flow of a "repulsive" energy function. https://objf.ai/papers/Turk-MIS-2002-10/ https://objf.ai/papers/Turk-MIS-2002-10/ Tue, 01 Oct 2002 00:00:00 GMT We introduce new techniques for modelling with interpolating implicit surfaces. This form of implicit surface was first used for problems of surface reconstruction and shape transformation, but the emphasis of our work is on model creation. These implicit. https://objf.ai/papers/Obrien-GMA-2002-08/ https://objf.ai/papers/Obrien-GMA-2002-08/ Thu, 01 Aug 2002 00:00:00 GMT 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 fracture occur due to interaction between plastic yielding and the fracture process. https://objf.ai/papers/Shen-MAR-2002-07/ https://objf.ai/papers/Shen-MAR-2002-07/ Mon, 01 Jul 2002 00:00:00 GMT 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 most prior work on inter- active deformation has relied on geometrically simple models and. https://objf.ai/papers/Obrien-SSR-2002-07/ https://objf.ai/papers/Obrien-SSR-2002-07/ Mon, 01 Jul 2002 00:00:00 GMT This paper describes a real-time technique for generating realistic and compelling sounds that correspond to the motions of rigid objects. By numerically precomputing the shape and frequencies of an object's deformation modes, audio can be synthesized. https://objf.ai/papers/Feldman-MAW-2002-07/ https://objf.ai/papers/Feldman-MAW-2002-07/ Mon, 01 Jul 2002 00:00:00 GMT 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 method combines previous work on snow accumulation with techniques for incompressible. https://objf.ai/papers/Shen-IBR-2001-08/ https://objf.ai/papers/Shen-IBR-2001-08/ Wed, 01 Aug 2001 00:00:00 GMT 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, by precomputing maps for diffuse and specular lighting terms, we use high. https://objf.ai/papers/Obrien-SSF-2001-08/ https://objf.ai/papers/Obrien-SSF-2001-08/ Wed, 01 Aug 2001 00:00:00 GMT 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 of physically based animation that use deformable models to simulate the behavior of. https://objf.ai/papers/Turk-ISI-2001-05/ https://objf.ai/papers/Turk-ISI-2001-05/ Tue, 01 May 2001 00:00:00 GMT Implicit surfaces are often created by summing a collection of radial basis functions. Recently, researchers have begun to create implicit surfaces that exactly interpolate a given set of points by solving a simple linear system to assign weights to each. https://objf.ai/papers/Yngve-AEX-2000-07/ https://objf.ai/papers/Yngve-AEX-2000-07/ Tue, 01 Aug 2000 00:00:00 GMT 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 through the surrounding medium. This disturbance determines the behavior of nearly. https://objf.ai/papers/Obrien-AFX-2000-12/ https://objf.ai/papers/Obrien-AFX-2000-12/ Sat, 01 Jul 2000 00:00:00 GMT 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, solid objects as they break, crack, or tear. When these objects deform beyond. https://objf.ai/papers/Obrien-AJP-2000-05/ https://objf.ai/papers/Obrien-AJP-2000-05/ Mon, 01 May 2000 00:00:00 GMT 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 to determine limb lengths, joint locations, and sensor placement for a human subject. https://objf.ai/papers/Obrien-CAP-2000-08/ https://objf.ai/papers/Obrien-CAP-2000-08/ Sat, 01 Jan 2000 00:00:00 GMT 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 motion" to refer to passive motions generated in response to the movements of. https://objf.ai/papers/Turk-STU-1999-08/ https://objf.ai/papers/Turk-STU-1999-08/ Sun, 01 Aug 1999 00:00:00 GMT Traditionally, shape transformation using implicit functions is performed in two distinct steps: 1) creating two implicit functions, and 2) interpolating between these two functions. We present a new shape transformation method that combines these two tasks. https://objf.ai/papers/Obrien-GMA-1999-08/ https://objf.ai/papers/Obrien-GMA-1999-08/ Sun, 01 Aug 1999 00:00:00 GMT In this paper, we augment existing techniques for simulating flexible objects to include models for crack initiation and propagation in three-dimensional volumes. By analyzing the stress tensors computed over a finite element model, the simulation determines. https://objf.ai/papers/Sumner-ASM-1999-03/ https://objf.ai/papers/Sumner-ASM-1999-03/ Fri, 01 Jan 1999 00:00:00 GMT 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, airplanes rarely leave jet trails in the sky, and most runners leave no footprints. In. https://objf.ai/papers/Hodgins-PHM-1998-12/ https://objf.ai/papers/Hodgins-PHM-1998-12/ Tue, 01 Dec 1998 00:00:00 GMT 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. This paper reports on experimental results indicating that a viewer’s perception. https://objf.ai/papers/Sumner-ASM-1998-06/ https://objf.ai/papers/Sumner-ASM-1998-06/ Mon, 01 Jun 1998 00:00:00 GMT 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, airplanes rarely leave jet trails in the sky, and most run- ners leave no footprints. https://objf.ai/papers/Obrien-CAP-1997-07/ https://objf.ai/papers/Obrien-CAP-1997-07/ Tue, 01 Jul 1997 00:00:00 GMT 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 the motion of the primary character, most research in computer animation has largely ignored. https://objf.ai/papers/Hodgins-DGM-1997-05/ https://objf.ai/papers/Hodgins-DGM-1997-05/ Thu, 01 May 1997 00:00:00 GMT 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, or clothing. This paper re- ports on experiments designed to ascertain whether a viewer’s. https://objf.ai/papers/Hodgins-AHA-1995-08/ https://objf.ai/papers/Hodgins-AHA-1995-08/ Tue, 01 Aug 1995 00:00:00 GMT This paper describes algorithms for the animation of men and women performing three dynamic athletic behaviors: running, bicycling, and vaulting. We animate these behaviors using control algorithms that cause a physically realistic model to perform the. https://objf.ai/papers/Obrien-DSS-1995-04/ https://objf.ai/papers/Obrien-DSS-1995-04/ Sat, 01 Apr 1995 00:00:00 GMT 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. The forces generated by the objects create waves and splashes on the surface of.