“A modeling system based on dynamic constraints” by Barzel and Barr

We present “dynamic constraints,” a physically-based technique for constraint-based control of computer graphics models. Using dynamic constraints, we build objects by specifying geometric constraints; the models assemble themselves as the elements move to satisfy the constraints. The individual elements are rigid bodies which act in accordance with the rules of physics, and can thus exhibit physically realistic behavior. To implement the constraints, a set of “constraint forces” is found, which causes the bodies to act in accordance with the constraints; finding these “constraint forces” is an inverse dynamics problem.

1. Armstrong, William W., and Mark W. Green, The dynamics of articulated rigid bodies for purposes of animation, in Visual Computer, Springer-Voting, 1985, pp. 231-240.
2. Barr, Alan H., Geometric Modeling and Fluid Dynamic Analysis of Swimming Spermatozoa, Ph.D. Dissertation, Rensselasr Polytechnic Institute, 1983
3. Barr, Alan H., Topics in Physically Based Modeling, to appear, Addison Wesley
4. Barr, Alan H., Brian Von Herren, Rouen Barrel, and John Snyder, Computational Techniques for the Self Assembly of Large Space Structures Proceedings of the 8th Princeton/SSI Conference on Space Manufacturing, Princeton New Jersey, May 6-9 1987, to be published by the American Institute of Aeronautics and Astronautics.
5. Boycu, William E., and DiPrima, Richard C., Elementary Differential Equations and Boundary Value Problems, John Wiley & Sons, New York, 1977.
6. Caltech studies in modeling and motion (videotape), in SIGGRAPH video Review #28, Visualization in Scientific Computing Computer Graphics, volume 21 number 6. ACM SIG- GRAPH, 1987
7. Fox, E.A., Mechanies, Harper and Row, New York, 1967
8. Gear, C. William, Numerical Initial Value Problems in Ordinary Differential Equations, Prentice-Hall, Englewood Cliffs, NJ, 1971
9. Goldstein, Herbert, Classical Mechanics, 2nd edition, Addison-Wesley, Reading, Massachusetts, 1983.
10. Golub, G., and Van Loan, C., Matrix Computatlons, Johns Hopkins University Press, Baltimore, 1983.
11. Isaacs, Paul M. and Michael F. Cohen, Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions, and Inverse Dynamics, Proc. SIGGRAPH 1987, pp. 215-224
12. Lengyel, Jed, Dynamic Assembly and Behavioral Simulation of the Flagellar Axoneme, in Caltech SURF Reports, 1987
13. Lien, Sheue-ling, and James T. Kajiya, A symbolic method for calculating the integral properties of arbitrary nonconvex polyhedra, IEEE Computer Graphics and Applications, Vol. 4 No. 10, Oct. 1984, pp. 35-41.
14. Misner, Charles W., Kip S. Thorae, and John Archibald Wheeler, Gravitation, W.H. Freeman and Co., San Francisco, 1973.
15. Press, William II., Brian P. Flannery, Saul A. Teukolsky, and William T. Vetterling, Numerical Recipes in C/The Art of Scientific Computing, Cambridge University Press, Cambridge, 1988.
16. Platt, John, and Alan Barfs Constraints on Flexible Objects, Submitted to SIGGRAPH 1988.
17. Ralston, Anthony, and Philip Rabinowitz, A First Course in Numerical Analysis, McGraw-Hill, New York, 1978.
18. Shoemake, Ken, Animating Rotation with Quaternion Curves, Computer Graphics, Vol. 19 No, 3, July 1985. pp. 245-254.
19. Terzoponlos, Demetri, John Platt, Alan Barr, and Kurt Fleischer Elastically Deformable Models, Proc. SIGGRAPH, 1987, pp. 205-214.
20. Witkin, Andrew, Kurt Fleiascher, and Alan Barr, Energy Constraints on Parametrized Models, Proc. SIGGRAPH 1987, pp. 225-232
21. Wilhelms, Jane, and Brian Barsky Using Dynamic Analysis To Animate Articulated Bodies Such As Humans and Robots, Graphics Interface, 1985.