This Article 
   
 Share 
   
 Bibliographic References 
   
 Add to: 
 
Digg
Furl
Spurl
Blink
Simpy
Google
Del.icio.us
Y!MyWeb
 
 Search 
   
A Fluid-Based Soft-Object Model
July/August 2002 (vol. 22 no. 4)
pp. 68-75
Daniel Nixon, Quest Computing
Richard Lobb, University of Auckland

Soft objects are those everyday objects that deform significantly in response to their normal environment. Examples include cushions, plasticine and balloons filled with treacle. We present a new physically based model for animating soft objects. The model consists of two components: an elastic surface and a compressible fluid. The surface is represented as a mass spring system. The fluid is modelled using finite difference approximations to the Navier-Stokes equations of fluid flow. Unlike models that use implicit surfaces, surface tension is a natural feature of the model. Furthermore, the model avoids the problem of volume variation that is inherent in implicit surface animation. We illustrate the behavior of the soft object in environments with gravity and collisions with planes.

1. A.R. Paterson, A First Course in Fluid Dynamics, Cambridge Univ. Press, Cambridge, UK, 1983.
2. M.P. Cani and M. Desbrun, Animation of Deformable Models Using Implicit Surfaces IEEE Trans. Visualization and Computer Graphics, vol. 3, no. 1, pp. 39-50, Jan.-Mar. 1997.
3. U. Gudukbay, B. Ozguc, and Y. Tokad, "A Spring Force Formulation for Elastically Deformable Models," Computers and Graphics, vol. 21, no. 3, 1997, pp. 335-346.
4. G. Miller, “The Motion Dynamics of Snakes and Worms,” Computer Graphics (Siggraph '88 Proc.), vol. 22, no. 4, pp. 169-173, 1988.
5. N. Foster and D. Metaxas, "Realistic Animation of Liquids," Proc. Graphics Interface 96, Canadian Human-Computer Communications Society, Toronto, May 1996, pp. 204-212.
6. J. Ferziger and M. Peric, Computational Methods for Fluid Dynamics, Springer-Verlag, Berlin, 1996.
7. D. Baraff and A. Witkin, "Physically Based Modeling: Principles and Practice," Siggraph 97 course notes,http://www.cs.cmu.edu/~baraffsigcourse/.
8. A. Van Gelder, Approximate Simulation of Elastic Membranes by Triangle Meshes J. Graphics Tools, vol. 3, pp. 21-42, 1998.
9. D.A. Nixon, A Fluid-Based Soft Object Model, master's thesis, University of Auckland, New Zealand, Feb. 1999.
10. D. Terzopoulos and K. Fleischer, "Modeling Inelastic Deformation: Viscoelasticity, Plasticity, Fracture," Computer Graphics (SIGGRAPH '88 Proc.), J. Dill, ed., vol. 22, pp. 269-278, Aug. 1988.
11. D.L. James and D.K. Pai, “ArtDefo: Accurate Real Time Deformable Objects,” Proc. SIGGRAPH '99, pp. 65-72, 1999.
12. J. Stam, "Stable Fluids," Proc. Siggraph 99, ACM, New York, Aug. 1999, pp. 121-128.
1. G. Wyvill, C. McPheeters, and B. Wyvill, "Data Structures for Soft Objects," The Visual Computer, vol. 2, no. 4, Apr. 1986, pp. 227-234.
2. D. Terzopoulos and K. Fleischer, "Modeling Inelastic Deformation: Viscoelasticity, Plasticity, Fracture," Computer Graphics (SIGGRAPH '88 Proc.), J. Dill, ed., vol. 22, pp. 269-278, Aug. 1988.
3. D.L. James and D.K. Pai, “ArtDefo: Accurate Real Time Deformable Objects,” Proc. SIGGRAPH '99, pp. 65-72, 1999.
4. G. Miller, “The Motion Dynamics of Snakes and Worms,” Computer Graphics (Siggraph '88 Proc.), vol. 22, no. 4, pp. 169-173, 1988.
5. M.P. Cani and M. Desbrun, Animation of Deformable Models Using Implicit Surfaces IEEE Trans. Visualization and Computer Graphics, vol. 3, no. 1, pp. 39-50, Jan.-Mar. 1997.
1. P.Y. T'so and B.A. Barsky, "Modeling and Rendering Waves: Wave-Tracing Using Beta-Splines and Reflective and Refractive Texture Mapping," ACM Trans. on Graphics, Vol. 6, No. 3, July 1987, pp. 191-214.
2. G. Miller and A. Pearce, "Globular Dynamics: A Connected Particle System for Animating Viscous Fluids," Computers and Graphics, vol. 13, no. 3, 1989, pp. 305-309.
3. D. Tonnesen, "Modeling Liquids and Solids Using Thermal Particles," Proc. Graphics Interface, Canadian Information Processing Soc., Toronto, 1991, pp. 255-262.
4. N. Foster and D. Metaxas, "Realistic Animation of Liquids," Proc. Graphics Interface 96, Canadian Human-Computer Communications Society, Toronto, May 1996, pp. 204-212.
5. J.X. Chen et al., "Real-time Fluid Simulation in a Networked Virtual Environment," IEEE Computer Graphics&Applications, vol. 17, no. 3, May/June 1997, pp. 52-61.
6. J. Stam, "Stable Fluids," Proc. Siggraph 99, ACM, New York, Aug. 1999, pp. 121-128.

Index Terms:
Soft Object, modeling, animation, fluid model.
Citation:
Daniel Nixon, Richard Lobb, "A Fluid-Based Soft-Object Model," IEEE Computer Graphics and Applications, vol. 22, no. 4, pp. 68-75, July-Aug. 2002, doi:10.1109/MCG.2002.1016700
Usage of this product signifies your acceptance of the Terms of Use.