prof.irfanessa.com » Physically-based Modeling http://prof.irfanessa.com Irfan Essa's Academic Activities Wed, 25 Jan 2012 23:42:09 +0000 en hourly 1 Thesis: Irfan Essa’s MS Thesis (1990): “Contact detection, collision forces and friction for physically based virtual world modeling” http://prof.irfanessa.com/1990/05/03/ms-thesis-1990/?utm_source=rss&utm_medium=rss&utm_campaign=ms-thesis-1990 http://prof.irfanessa.com/1990/05/03/ms-thesis-1990/#comments Thu, 03 May 1990 20:02:19 +0000 Irfan Essa http://essa.org/irfan/wp/?p=5 Contact detection, collision forces and friction for physically based virtual world modeling
  • Essa (1990), “Contact Detection, Collision Forces and Friction for Physically Based Virtual World Modeling,” Master Thesis, Massachusetts Institute Technology, 1990. [WEBSITE] [BLOG] [BIBTEX] 
    @mastersthesis{1990-Essa-CDCFFPBVWM,
  Author = {I. Essa},
  Blog = {http://prof.irfanessa.com/1990/05/03/ms-thesis-1990/},
  Date-Modified = {2011-12-13 14:50:49 +0000},
  Month = {June},
  School = {Massachusetts Institute Technology},
  Title = {Contact Detection, Collision Forces and Friction for Physically Based Virtual World Modeling},
  Url = {http://dspace.mit.edu/handle/1721.1/14054?mode=simple&submit_simple=Show+simple+item+record},
  Year = {1990},
  Bdsk-Url-1 = {http://dspace.mit.edu/handle/1721.1/14054?mode=simple&submit_simple=Show+simple+item+record}}

Abstract

Detection of contact and calculation of collision forces is an important problem in any kind of physical multi-body simulation. For computer graphics and physically based animation it is especially important to devise methods that combine efficient computational methods with powerful existing graphics tools if one is to obtain a realistic, real-time virtual world. Most of physical simulations are computationally expensive, and thus, it is difficult to set up any simulations that are stable and have a real-time response.

Efficient methods for contact detection and response for physical interactions of deformable objects in physically based virtual world environments are presented. Contact, collision and friction of objects in virtual worlds are specifically addressed in the framework of differential geometry and finite element modeling. A statistical approach is introduced for estimation and control of the physical simulation. These methods employ statistical estimation of contact between stochastically defined surfaces and linear control theory for estimation and control to obtain stable forward time simulations. By mapping from the statistical domain to the geometric domain and then to the physical domain, we have been able to obtain efficient physical simulations of multi-body systems.

]]> http://prof.irfanessa.com/1990/05/03/ms-thesis-1990/feed/ 0 Paper I3DG (1990) “The ThingWorld modeling system: virtual sculpting by modal forces” http://prof.irfanessa.com/1990/03/13/thingworld-i3gd1990/?utm_source=rss&utm_medium=rss&utm_campaign=thingworld-i3gd1990 http://prof.irfanessa.com/1990/03/13/thingworld-i3gd1990/#comments Tue, 13 Mar 1990 23:01:50 +0000 Irfan Essa http://prof.irfanessa.com/?p=1107 The ThingWorld modeling system: virtual sculpting by modal forces
  • Pentland, Essa, Friedmann, Horowitz, and Sclaroff (1990), “The Thingworld Modeling System: Virtual Sculpting by Modal Forces,” ACM SIGGRAPH Proceedings of Symposium on Interactive 3D Graphics (I3DG), vol. 24, iss. 2, pp. 143-144, 1990. [PDF] [DOI] [BLOG] [BIBTEX] 
    @article{1990-Pentland-TMSVSMF,
  Author = {A. Pentland and I. Essa and M. Friedmann and B. Horowitz and S. E. Sclaroff},
  Blog = {http://prof.irfanessa.com/1990/03/13/thingworld-i3gd1990/},
  Date-Modified = {2011-12-13 23:07:06 +0000},
  Doi = {10.1145/91394.91434},
  Journal = {ACM SIGGRAPH Proceedings of Symposium on Interactive 3D Graphics (I3DG)},
  Month = {March},
  Number = {2},
  Pages = {143--144},
  Pdf = {http://www.cc.gatech.edu/~irfan/p/1990-Pentland-TMSVSMF.pdf},
  Title = {The Thingworld Modeling System: Virtual Sculpting by Modal Forces},
  Volume = {24},
  Year = {1990}}

Abstract

We describe a real-time solid modeling system that is based on the physical analogy of forming clay by applying forces. The system is implemented by simulating real materials as they react to user-supplied forces. Unlike other physically-based modeling approaches, the Thingworld system allows the user to restrict forming action to simple global deformations during the initial “roughing in” phase of modeling, and then later concern themselves with detailing. The Thingworld system also allows users to automatically model existing objects by using measurements taken from the object’s surface. These measurements are used to generate artificial forces that mold the computer model much as a human would mold a clay model. Timed examples for constructing solid models are shown.

via The ThingWorld modeling system: virtual sculpting by modal forces.

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