“Visual simulation of clouds” by Gardner

Clouds present serious problems to standard computer image generation techniques because clouds do not have well-defined surfaces and boundaries. In addition, clouds contain varying degrees of translucence, and their amorphous structure can change with time. Although several approaches to cloud simulation have produced impressive results, they have relied on complex mathematical models which produce high computation costs for a single image.This paper describes a new approach to cloud simulation using simple planar and curved surfaces whose surface shading and translucence are modulated by a mathematical texturing function. This approach represents the appearance of clouds with enough realism for a wide range of visual simulation but does so at a reasonable computational cost, allowing the generation of sequences of images on small minicomputers. In addition, the cloud model can be constructed in a straightforward manner.

1. B~inn, J.F. Light reflection functions for simulation of clouds and dusty surfaces. Computer Graphics 16, 3 (Jul 1982), 21-29.
2. Gardner, G.Y. Computer-generated texturing to model real -world features. Proc 1st Interservice/Industry Training Equipment Conf, Orlando, FL (Nov 1979) 239-245.
3. Gardner, G.Y. Non-edge CIG. SIGGRAPH Video Review, Issue 11 (Oct 1983).
4. Gardner, G. Y. and Rulo~, R.S. Producing high scene content with perspective validity. Proc 1984 IMAGE Ill Conf, Phoenix, AZ (May 1984), 79-94.
5. Gardner, G.Y. Simulation of natural scenes using textured quadric surfaces. Computer Graphics 18, 3 (Jul 1984), 11-20.
6. Gardner, G.Y. Beethoven’s Sixth in CIG. SIGGRAPH Video Review, Issue 17 (Aug 1984).
7. Kajiya, J.T. and Von Herzen, B.P. Ray tracing volume densities, Computer Graphics 18, 3 (Jul 1984), 165-173.
8. Mason, B.J. The Physics of Clouds. Oxford University Press, LOne{on (1957).
9. Max, N. The simulation of natural phenomena panel. Computer Graphics 17, 3 (~ul 1983), 137-139.
10. Voss, R. Fourier synthesis of gaussian fractals” 1/f noises, landscapes, and flakes. State of the Art in Image Synthesis. Tutorial No. 10, SIGGRAPH ’83 Conf, Detroit, MI (Jul 1983).