News
Nov, 2017: Organizers of the French VR conference and trade show Laval Virtual immersed themselves into a variety of different virtual environments
where they learned about current projects of the Computer Graphics & Virtual Reality lab at the University of Bremen (full report, in German).
Jun 17, 2017: Haptic and hand tracking demos at the Open Campus 2017.
FebApr 2017: David Vilela (Mechanical Engineering Laboratory, University of Coruna, Spain) visited our lab.
He is working on benchmarks to compare different intersection calculation methods in collisions, and also different force models.
Feb 2017: G. Zachmann and J. Teuber visited the Mahidol University in Bangkok,
Thailand as part of a delegation from the University of Bremen.
The goal of the visit was to foster the cooperation between the two universities and lay groundwork for future colaborations.
Jun 2016: Radio Bremen visited our lab to film the works of the Creative Unit "IntraOperative Information" for a news magazine on the local TV station. Click here for the film
at Radio Bremen. And Click here for the same film on our Website.
May 16, 2016: Patrick Lange was honored with the SIGSIM Best PhD Award at the ACM SIGSIM
PADS Conference 2016.
Jun 1921, 2015: G. Zachmann gives invited talk at the
DAADStipendiatentreffen in Bremen, Germany.
Jun 2015: Haptic and hand tracking demos at the Open Campus 2015.
Dec 0810, 2014:
ICATEGVE 2014 and EuroVR 2014
conferences at the University of Bremen organized by G. Zachmann.
Sep 2526, 2014:
GI VR/AR 2014 conference at the University of Bremen organized by G. Zachmann.
Sep 2425, 2014: VRIPHYS 2014 conference at the University of Bremen organized by G. Zachmann .
Feb 4, 2014: G. Zachmann gives invited talk on Interaction Metaphors for Collaborative 3D Environments
at Learntec.
Jan 2014: G. Zachmann got invited to be a Member of the Review Panel in the Human Brain Project for the Competitive Call for additional project partners
Nov 2013: Invited Talk at the "Cheffrühstück 2013"
Oct 2013: PhD thesis of Rene Weller published in the Springer Series on Touch and Haptic Systems.
Jun 2013: G. Zachmann participated in the Dagstuhl Seminar Virtual Realities (13241)
Jun 2013: Haptic and hand tracking demos at the Open Campus 2013.
Jun 2013: Invited talk at Symposium für Virtualität und Interaktion 2013 in Heidelberg by Rene Weller.
Apr 2013: Rene Weller was honored with the EuroHaptics Ph.D Award at the IEEE World Haptics Conference 2013.
Jan 2013: Talk at the graduation ceremony of the University of Bremen by Rene Weller.
Oct 2012: Invited Talk by G. Zachmann at the DLR VROOS Workshop Servicing im Weltraum  Interaktive VRTechnologien zum OnOrbit Servicing in Oberpfaffenhofen, Munich, Germany.
Oct 2012: Daniel Mohr earned his doctorate in the field of visionbased pose estimation.
Sept 2012: G. Zachmann: Keynote Talk at ICEC 2012, 11th International Conference on Entertainment Computing.
Sep 2012: "Best Paper Award" at GI VR/AR Workshop in Düsseldorf.
Sep 2012: Rene Weller earned his doctorate in the field of collision detection.
Aug 2012: GIVRARCalendar 2013 is available!
Publications
Additional Material
Here are some additional plots showing various aspects of a comparison of
the performance of the old traversal scheme (red) and the new one (green):


Average 
Maximum 
Object 
Obj name 
Time 
Num overlap tests 
Num DOP transforms 
Num nodes visited 
Num pgon intersection tests 
Time 
Num overlap tests 
Num DOP transforms 
Num nodes visited 
Num pgon intersection tests 

Cover (Abdeckung), 30477 polygons each 











Happy Buddha (buddha), 125,000 polygons each 











Front Light (scheinwerfer), 30075 polygons each 











Door Lock (schloss), 26136 polygons each 
    
    

Car Body (sharan), 28167 polygons each 
    
    
The time plots show the collision detection time depending on the
"distance" between the two objects, for one polygon count (as given in the
column "obj name").
The "num" plots show statistics of various characteristic numbers (see
below for an explanation), depending on the polygon count.
Benchmarking procedure:
two identical objects are positioned
at a certain distance d = d_{start} from each other. The distance is
computed between the centers of the bounding boxes of the two objects;
objects are scaled uniformly so they fit in a cube of size
[1,+1]^{3}. Then,
one of them performs a full tumbling turn about the z and the xaxis by a
fixed, large number of small steps (5000). With each step, a collision
query is done, and the average collision detection time for a complete
revolution at that distance is computed. Then, d is decreased, and a new
average collision detection time is computed.
The collision detection algorithm always stopped whenever the first pair of
intersecting polygons was found.
Explanation of the columns:
 Time: average collision detection time for a certain
distance; the average was taken over many collision queries with
different object orientations (see above).
 Num overlap tests: average number of BV pair overlap tests during
one collision test.
 Num DOP transforms: average number of DOP transformations that are
performed during one collision test.
 Num nodes visited: total average number of BV tree nodes that are
visited during one collision test; this counts both tree's nodes, and
multiple visits of the same node are counted multiple times. So, this
number is proportional to the amount of data that must be transfered
from memory during collision test.
 Num pgon intersection tests: average number of polygonpolygon
intersection tests; this is the number of leaf pairs that are reached
during one collision test without finding a collision.
The maxium columns are exactly the same as the average, except that here,
the maximum over all rotations (with one distance) is listed.