From: owner-3dui@hitl.washington.edu on behalf of Anders Backman [andersb@cs.umu.se] Sent: Tuesday, December 19, 2000 3:49 AM To: 3-D User Interaction Mailing List Subject: Modelling of user induced forces Hi, We use magnetic tracking to interact with objects in a VR-model. The objects are rigid-bodies simulated in real time. We introduce user interaction using a constraint that reduces all six degrees of freedom (MathEngine's FixedPathFixedOrientation joint) of the object and we integrate the resulting problem (semi) implicitly for stability. As usual, user induced forces tend to become too large and thus we need to limit the forces by using a non-linear joint that becomes softer with increasing force until it suddenly breaks. Does anyone know of a systematic study of such models, or other aspects of introducing user induced forces into a physical simulation? Cheers, /Anders ________________________________________________________________ Anders Backman Email: andersb@cs.umu.se HPC2N/VRlab Phone: +46 (0)90-786 9936 Umea university Cellular: +46 (0)70-392 64 67 S-901 87 UMEA SWEDEN Fax: +46 90-786 6126 http://www.cs.umu.se/~andersb