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200
Fast continuous collision detection between rigid bodies
 Proc. of Eurographics (Computer Graphics Forum
, 2002
"... This paper introduces a fast continuous collision detection technique for polyhedral rigid bodies. As opposed to most collision detection techniques, the computation of the first contact time between two objects is inherently part of the algorithm. The method can thus robustly prevent objects interp ..."
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Cited by 70 (13 self)
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This paper introduces a fast continuous collision detection technique for polyhedral rigid bodies. As opposed to most collision detection techniques, the computation of the first contact time between two objects is inherently part of the algorithm. The method can thus robustly prevent objects interpenetrations or collisions misses, even when objects are thin or have large velocities. The method is valid for general objects (polygon soups), handles multiple moving objects and acyclic articulated bodies, and is efficient in low and high coherency situations. Moreover, the method can be used to speed up existent continuous collision detection methods for parametric or implicit rigid surfaces. The collision detection algorithms have been successfully coupled to a realtime dynamics simulator. Various experiments are conducted that show the method’s ability to produce highquality interaction (precise objects positioning for example) between models up to tens of thousands of triangles, which couldn’t have been performed with previous continuous methods. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Animation Virtual Reality 1.
Collisions and Perception
 ACM Transactions on Graphics
, 2001
"... Level of Detail (LoD) techniques for realtime... In this paper, we are particularly interested in the problem of realistic collision simulation in scenes where large numbers of objects are colliding and processing must occur in realtime. An interruptible and therefore degradable collision handling ..."
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Cited by 64 (7 self)
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Level of Detail (LoD) techniques for realtime... In this paper, we are particularly interested in the problem of realistic collision simulation in scenes where large numbers of objects are colliding and processing must occur in realtime. An interruptible and therefore degradable collision handling mechanism is used and the perceptual impact of this degradation is explored. We look for ways in which we can optimise the realism of such simulations and describe a series of psychophysical experiments that investigated different factors affecting collision perception, including eccentricity, separation, distractors, causality and accuracy of physical response. Finally, strategies for incorporating these factors into a perceptually adaptive realtime simulation of large numbers of visually similar objects are presented.
Realtime Collision Detection for Virtual Surgery
 In Proc. Computer Animation '99
, 1999
"... We present a simple method for performing realtime collision detection in a virtual surgery environment. The method relies on the graphics hardware for testing the interpenetration between a virtual deformable organ and a rigid tool controlled by the user. The method enables to take into account t ..."
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Cited by 60 (8 self)
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We present a simple method for performing realtime collision detection in a virtual surgery environment. The method relies on the graphics hardware for testing the interpenetration between a virtual deformable organ and a rigid tool controlled by the user. The method enables to take into account the motion of the tool between two consecutive time steps. For our specic application, the new method runs about a hundred times faster than the well known orientedboundingboxes tree method [5].
Virtual Environments for Medical Training: Graphical and Haptic Simulation of Common Bile Duct Exploration
 IEEE/ASME Transactions on Mechatronics (special issue on Haptic Displays and Applications
, 2001
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Efficient Pointbased Rendering Techniques for Haptic Display of Virtual Objects
 Presence:Teleoper. Virtual Env
, 1999
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Sensation Preserving Simplification for Haptic Rendering
, 2003
"... We introduce a novel "sensation preserving" simplification algorithm for faster collision queries between two polyhedral objects in haptic rendering. Given a polyhedral model, we construct a multiresolution hierarchy using "filtered edge collapse", subject to constraints imposed ..."
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Cited by 49 (14 self)
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We introduce a novel "sensation preserving" simplification algorithm for faster collision queries between two polyhedral objects in haptic rendering. Given a polyhedral model, we construct a multiresolution hierarchy using "filtered edge collapse", subject to constraints imposed by collision detection. The resulting hierarchy is then used to compute fast contact response for haptic display. The computation model is inspired by human tactual perception of contact information. We have successfully applied and demonstrated the algorithm on a timecritical collision query framework for haptically displaying complex objectobject interaction. Compared to existing exact contact query algorithms, we observe noticeable performance improvement in update rates with little degradation in the haptic perception of contacts.
Evaluating the Visual Fidelity of Physically Based Animations
, 2003
"... For many systems that produce physically based animations, plausibility rather than accuracy is acceptable. We consider the problem of evaluating the visual quality of animations in which physical parameters have been distorted or degraded, either unavoidably due to realtime framerate requirements ..."
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Cited by 48 (4 self)
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For many systems that produce physically based animations, plausibility rather than accuracy is acceptable. We consider the problem of evaluating the visual quality of animations in which physical parameters have been distorted or degraded, either unavoidably due to realtime framerate requirements, or intentionally for aesthetic reasons. To date, no generic means of evaluating or predicting the fidelity, either physical or visual, of the dynamic events occurring in an animation exists. As a first step towards providing such a metric, we present a set of psychophysical experiments that established some thresholds for human sensitivity to dynamic anomalies, including angular, momentum and spatiotemporal distortions applied to simple animations depicting the elastic collision of two rigid objects. In addition to finding significant acceptance thresholds for these distortions under varying conditions, we identified some interesting biases that indicate nonsymmetric responses to these distortions (e.g., expansion of the angle between postcollision trajectories was preferred to contraction and increases in velocity were preferred to decreases). Based on these results, we derived a set of probability functions that can be used to evaluate the visual fidelity of a physically based simulation. To illustrate how our results could be used, two simple case studies of simulation levels of detail and constrained dynamics are presented.
Collision Detection for Continuously Deforming Bodies
, 2001
"... Fast and accurate collision detection between geometric bodies is essential in application areas like virtual reality, animation, simulation, games and robotics. In this work, we address the collision detection problem in applications where deformable bodies are used, which change their overall sh ..."
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Cited by 47 (1 self)
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Fast and accurate collision detection between geometric bodies is essential in application areas like virtual reality, animation, simulation, games and robotics. In this work, we address the collision detection problem in applications where deformable bodies are used, which change their overall shape every time step of the simulation. We propose and evaluate suitable bounding volume trees for deforming bodies that can be prebuilt and then updated very efficiently during simulation. Several heuristics for updating the trees due to deformations are compared to each other. By combining a topdown and a bottomup update strategy into a hybrid tree update method, promising results were achieved. Experiments show that our approach is four to five times faster than a previously leading method.
BOXTREE: A Hierarchical Representation for Surfaces in 3D
, 1996
"... We introduce the boxtree, a versatile data structure for representing triangulated or meshed surfaces in 3D. A boxtree is a hierarchical structure of nested boxes that supports efficient ray tracing and collision detection. It is simple and robust, and requires minimal space. In situations where sto ..."
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Cited by 46 (7 self)
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We introduce the boxtree, a versatile data structure for representing triangulated or meshed surfaces in 3D. A boxtree is a hierarchical structure of nested boxes that supports efficient ray tracing and collision detection. It is simple and robust, and requires minimal space. In situations where storage is at a premium, boxtrees are effective alternatives to octrees and BSP trees. They are also more flexible and efficient than Rtrees, and nearly as simple to implement. Keywords: collision detection, hierarchical data structures, ray shooting. 1. Introduction In 1981 Ballard 1 presented a simple data structure for representing digitized curves by means of nested strips. This work is an attempt to generalize his strip tree structure to the case of surfaces in 3D. As is well known, curves can seem quite tame when compared to surfaces. For example, collision detection in 3D is orders of magnitude more difficult than in 2D. Expectedly, generalizing a strip tree into a boxtree raises a ...
Supplement for realtime soft shadows in dynamic scenes using spherical harmonic exponentiation
 Microsoft Corporation. available on the SIGGRAPH 2006 Conference DVD
, 2006
"... Previous methods for soft shadows numerically integrate over many light directions at each receiver point, testing blocker visibility in each direction. We introduce a method for realtime soft shadows in dynamic scenes illuminated by large, lowfrequency light sources where such integration is impr ..."
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Cited by 44 (9 self)
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Previous methods for soft shadows numerically integrate over many light directions at each receiver point, testing blocker visibility in each direction. We introduce a method for realtime soft shadows in dynamic scenes illuminated by large, lowfrequency light sources where such integration is impractical. Our method operates on vectors representing lowfrequency visibility of blockers in the spherical harmonic basis. Blocking geometry is modeled as a set of spheres; relatively few spheres capture the lowfrequency blocking effect of complicated geometry. At each receiver point, we compute the product of visibility vectors for these blocker spheres as seen from the point. Instead of computing an expensive SH product per blocker as in previous work, we perform inexpensive vector sums to accumulate the log of blocker visibility. SH exponentiation then yields the product visibility vector over all blockers. We show how the SH exponentiation required can be approximated accurately and efficiently for loworder SH, accelerating previous CPUbased methods by a factor of 10 or more, depending on blocker complexity, and allowing realtime GPU implementation.