We present new distance computation algorithms using hierarchies of rectangular swept spheres. Each bounding volume of the tree is described as the Minkowski sum of a rectangle and a sphere, and fits tightly to the underlying geometry. We present accurate and efficient algorithms to build the hierarchies and perform distance queries between the bounding volumes. We also present traversal techniques for accelerating distance queries using coherence and priority directed search. These algorithms have been used to perform proximity queries for applications including virtual prototyping, dynamic simulation, and motion planning on complex models. As compared to earlier algorithms based on bounding volume hierarchies for separation distance and approximate distance computation, our algorithms have achieved significant speedups on many benchmarks.

We present a framework for fast and accurate collision detection for haptic interaction with polygonal models. Given a model, we pre-compute a hybrid hierarchical representation, consisting of uniform grids and trees of tight-fitting oriented bounding box trees (OBB-Trees). At run time, we use hybrid hierarchical representations and exploit frame-to-frame coherence for fast proximity queries. We describe a new overlap test, which is specialized for intersection of a line segment with an oriented bounding box for haptic simulation and takes 6-36 operations excluding transformation costs. The algorithms have been implemented as part of H-COLLIDE and interfaced with a PHANToM arm and its haptic toolkit, GHOST, and applied to a number of models. As compared to the commercial implementation, we are able to achieve up to 20 times speedup in our experiments and sustain update rates over 1000 Hz on a 400 MHz Pentium II.

Article OBBTree: a hierarchical structure for rapid interference detection Share on Authors: S. Gottschalk Department of Computer Science, University of North Carolina, Chapel Hill, NC Department of Computer Science, University of North Carolina, Chapel Hill, NCView Profile , M. C. Lin Department of Computer Science, University of North Carolina, Chapel Hill, NC and U.S. Army Research Office Department of Computer Science, University of North Carolina, Chapel Hill, NC and U.S. Army Research OfficeView Profile , D. Manocha Department of Computer Science, University of North Carolina, Chapel Hill, NC Department of Computer Science, University of North Carolina, Chapel Hill, NCView Profile Authors Info & Claims SIGGRAPH '96: Proceedings of the 23rd annual conference on Computer graphics and interactive techniquesAugust 1996 Pages 171–180https://doi.org/10.1145/237170.237244Online:01 August 1996Publication History 959citation5,396DownloadsMetricsTotal Citations959Total Downloads5,396Last 12 Months262Last 6 weeks40 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

We describe two instances in which precise mechanical calibration of virtual environments equipment has been replaced by automated algorithmic calibration through software that encapsulates the hardware design and uses a goal-based approach to adjust calibration parameters.We describe a back-projection system for adjusting the assumed locations of beacons in a head-mounted display tracking system; the calculated errors in the navigation system are used to compute adjustments to the beacon positions to reduce such errors.In a second application, a piggyback headtracking/hand-tracking system is calibrated by a similar reduction of computed errors.

An optoelectronic head-tracking system for head-mounted displays is described. The system features a scalable work area that currently measures 10' x 12', a measurement update rate of 20-100 Hz with 20-60 ms of delay, and a resolution specification of 2 mm and 0.2 degrees. The sensors consist of four head-mounted imaging devices that view infrared lightemitting diodes (LEDs) mounted in a 10' x 12' grid of modular 2' x 2' suspended ceiling panels. Photogrammetric techniques allow the head's location to be expressed as a function of the known LED positions and their projected images on the sensors. The work area is scaled by simply adding panels to the ceiling's grid. Discontinuities that occurred when changing working sets of LEDs were reduced by carefully managing all error sources, including LED placement tolerances, and by adopting an overdetermined mathematical model for the computation of head position: space resecfion by collinearity. The working system was demonstrated in the Tomorrow's Realities gallery at the ACM SIGGRAPH '91 conference.