This Article 
 Bibliographic References 
 Add to: 
Faking Dynamics of Ropes and Springs
May-June 1997 (vol. 17 no. 3)
pp. 31-39
This article describes a simple method for modeling flexible linear bodies such as ropes and springs, using no dynamic simulation, procedural animation, or constraint methods-animators create motion by adjusting the shape of models over time using traditional keyframe methods. The approach taken is to provide a default natural rest shape and provide controls that perform gross modification and wave-shaped deformation of the rest shape. The resulting models provide animators with intuitive control and the means to interactively create motion that is both visually plausible and tailored to the frame-to-frame needs of particular animations. This technique has been used successfully in animation production over the past few years, in particular for various ropes and the "Slinky Dog" in the movie Toy Story.

1. J. Lasseter, "Principles of Traditional Animation Applied to 3D Computer Animation," Computer Graphics (Proc. Siggraph), Vol. 21, No. 4, July 1987, pp. 35-44.
2. R. Barzel and A.H. Barr, "A Modeling System Based on Dynamic Constraints," Computer Graphics (Proc. Siggraph), Vol. 22, No. 4, Aug. 1988, pp. 179-188.
3. Z. Liu, S.J. Gortler, and M.F. Cohen, "Hierarchical Spacetime Control," Proc. Annual Conf. Series ACM Siggraph, ACM Press, New York, 1994, pp. 35-42.
4. A. Pentland and J. Williams, “Good Vibrations: Modal Dynamics for Graphics and Animation,” Proc. ACM SIGGRAPH, pp. 215-222, 1989.
5. J.E. Chadwick,D.R. Haumann,, and R.E. Parent,“Layered construction for deformable animated characters,” Computer Graphics (SIGGRAPH’89 Proceedings), vol. 23, no. 3, pp. 243-252, 1989.
6. D. Terzopoulos and A. Witkin, "Physically Based Models with Rigid and Deformable Components," Proc. Graphics Interface, Morgan Kaufmann, Palo Alto, Calif., 1988, pp. 146-154.
7. R. Barzel, J.F. Hughes, and D. Wood, "Plausible Motion Simulation for Computer Graphics Animation," Eurographics Workshop on Animation and Simulation, Springer Verlag, New York, 1996, pp. 183-197.
8. W.T. Reeves, E.F. Ostby, and S.J. Leffler, "The Menv Modeling and Animation Environment," J. of Visualization and Computer Animation, Vol. 1, 1990, pp. 33-40.
9. R.P. Feynman, R.B. Leighton, and M. Sands, The Feynman Lectures on Physics, Vol. 1, Addison-Wesley, Reading, Mass., 1963.
1. R.H. Bartels, J.C. Beatty, and B.A. Barsky, An Introduction to Splines for Use in Computer Graphics and Geometric Modeling, Morgan Kaufmann, Los Altos, Calif., 1987.
2. J. Weil,“The synthesis of cloth objects,” Computer Graphics (SIGGRAPH’86 Proc.), D.C. Evans and R.J. Athay, eds., vol. 20, pp. 49-54, Aug. 1986.
3. J. Bloomenthal, "Calculation of Reference Frames along a Space Curve," Graphics Gems, A.S. Glassner, ed., Academic Press, Boston, 1990, pp. 567-571.
4. A.H. Barr, "Global and Local Deformations of Solid Primitives," Computer Graphics (Proc. Siggraph), Vol. 18, No. 3, July 1984, pp. 21-30.

Ronen Barzel, "Faking Dynamics of Ropes and Springs," IEEE Computer Graphics and Applications, vol. 17, no. 3, pp. 31-39, May-June 1997, doi:10.1109/38.586016
Usage of this product signifies your acceptance of the Terms of Use.