Publications



Stable 6-DOF Haptic Rendering with Inner Sphere Trees

Rene Weller, Gabriel Zachmann

Based on our new geometric data structure, the inner sphere trees, we present a fast and stable uniform algorithm for proximity and penetration volume queries between watertight objects at haptic rates. Moreover, we present a multi-threaded version of the penetration volume computation for time-critical haptic rendering that is based on separation lists and the novel notion of expected overlapping volumes. Finally, we show how to use the penetration volume to compute continuous contact forces and torques that enable a stable rendering of 6-DOF penalty-based distributed contacts.

Published:

Proceedings of International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (IDETC/CIE), San Diego, USA, 30 August - 02 September 2009. Virtual Environments and Systems - 2009 Best Paper Award. [BibTex]

Files:

     IDETC/CIE Presentation (ppt, 15MB)
     Simulation Video wmv, mov
     Interaction Video wmv, mov
     Bones Video wmv, mov
     758 Video wmv, mov
     Pin in Hole Benchmark Video wmv, mov

Links:

     Project Homepage

A Unified Approach for Physically-Based Simulations and Haptic Rendering

Rene Weller, Gabriel Zachmann

Since the visual feedback and effects of today’s games have become extremely mature, it will be more and more important for games to provide realistic feedback to other senses, such as our haptic sense. On the hardware side, this has become possible in recent years by the advent of first inexpensive haptic devices on the consumer market, such as the Falcon from Novint. Research on force-feedback devices and algorithms has been done over 10 years, and has only fairly recently been introduced to games. However, while there is a large body of research on how to render forces given a collision and its contact information, the computation of the latter for massive models is still a challenge. First of all, this is due to the much higher effort to compute contact information. Second, this is due to the update rates that are necessary for haptic rendering, which need to be much higher than for visual rendering, i.e., 250–1000 Hz. And third, defining the contact information such that continuous contact forces can be derived is not always obvious. Therefore, one of the major challenges in haptic rendering for games is the computation of continuous forces at haptic rates. A solution to this challenge can also be utilized to do physically-based simulation of rigid bodies, which has become increasingly popular in games over the past few years. In this paper, we take advantage of the fact that in rendering haptic forces, as well as in most real-time applications that involve physically-based simulation, an absolutely correct determination of the forces acting on the virtual objects is not necessary.

Published:

ACM SIGGRAPH Video Game Proceedings , New Orleans, USA, August 2009. [BibTex]

Files:

     Siggraph Paper (pdf, 4MB)
     Siggraph Presentation (ppt, 25MB)
     Simulation Video wmv, mov
     Interaction Video wmv, mov
     Armadillo Video wmv, mov
     Screwdriver Video wmv, mov
     Bozzle Video wmv, mov

Links:

     Project Homepage

Inner Sphere Trees for Proximity and Penetration Queries

Rene Weller, Gabriel Zachmann

We present a novel geometric data structure for approximate collision detection at haptic rates between rigid objects. Our data structure, which we call inner sphere trees, supports different kinds of queries, namely, proximity queries and a new method for interpenetration computation, the penetration volume, which is related to the water displacement of the overlapping region and, thus, corresponds to a physically motivated force. The main idea is to bound objects from the inside with a set of non-overlapping spheres. Based on such sphere packings, a “inner bounding volume hierarchy” can be constructed. In order to do so, we propose to use an AI clustering algorithm, which we extend and adapt here. The results show performance at haptic rates both for proximity and penetration volume queries for models consisting of hundreds of thousands of polygons.

Published:

2009 Robotics: Science and Systems Conference (RSS), Seattle, USA, 28 June - 01 July 2009. [BibTex]

Files:

     RSS paper (pdf, 6MB),
     RSS poster (pdf, 2MB)
     Technical Report (pdf, 6MB), [BibTex]

Links:

     Project Homepage


A Benchmarking Suite for Static Collision Detection Algorithms

Sven Trenkel, René Weller, Gabriel Zachmann

In this paper, we present a benchmarking suite that allows a systematic comparison of pairwise static collision detection algorithms for rigid objects. The pdf-file contains a slightly extended version of the original published paper.

Published

International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG), Plzen, Czech Republic, January 29 - February 1, 2007.[BibTex]

Files:

     Paper (pdf, 1.0MB)
     Slides (pdf, 5.4MB)
     Video of configuration generation (avi, 16.6MB)


Kinetic Separation Lists for Continuous Collision Detection of Deformable Objects

Gabriel Zachmann, René Weller

In this paper, we present a new acceleration scheme for continuous inter- and intra-collision detection of deformable objects. The pdf-file contains a slightly extended version of the original published paper (Section 6.2).

Published

Third Workshop in Virtual Reality Interactions and Physical Simulation (Vriphys), Madrid, Spain, 6/7 November 2006. [BibTex]

Files:

     Paper (pdf, 0.7MB)
     Slides (pdf, 4.9MB)


Kinetic Bounding Volume Hierarchies for Deformable Objects

Gabriel Zachmann, René Weller

In this paper, we present novel algorithms for updating bounding volume hierarchies of objects undergoing arbitrary deformations.

Published

ACM Int'l Conf. on Virtual Reality Continuum and Its Applications (VRCIA), Hong Kong, China, 14-17 June 2006.[BibTex]

Files:

     Paper (pdf, 1MB)
     Slides (pdf, 6.0 MB)



A Model for the Expected Running Time of Collision Detection using AABB Trees

René Weller, Jan Klein, Gabriel Zachmann

In this paper, we propose a model to estimate the expected running time of hierarchical collision detection that utilizes AABB trees, which are a frequently used type of bounding volume (BV).

Published

12th Eurographics Symposium on Virtual Environments (EGVE), Lisbon, Portugal, 8-10 May 2006.[BibTex]

Files:

     Paper, on-screen version (pdf, 1.6 MB)
     Paper, print version (pdf, 1.6 MB)
     Slides (pdf, 2.5 MB)



Kinetic Bounding Volume Hierarchies for Collision Detection of Deformable Objects

Gabriel Zachmann, René Weller

In this paper, we present novel algorithms for updating bounding volume hierarchies of objects undergoing arbitrary deformations.

Published

Technical Report, IfI-06-02, TU Clausthal, 2006.

Files:

     Paper (pdf, 1.2MB)
Rene Weller
Am Ludwiger Graben 5
38678 Clausthal-Zellerfeld

Tel: +49 5323 983005