Volume tracing of atmospheric environments

Current three-dimensional computer graphics assumes a vacuum space. The inclusion of atmosphere is essential for the modeling and rendering of natural phenomena. This paper presents a method of modeling atmospheric effects and rendering them using a volume tracing renderer. The model is built within a framework called the atmospheric cube. The atmospheric cube, or the A-cube, is a finite volume that encloses the three-dimensional scene to be modeled. The atmosphere is defined by particles of varying radii, which are distributed over the cube. The distribution of particles determines the density of atmosphere. The interaction of light with the atmosphere is divided into four cases to capture the characteristics of the atmospheric illumination by particles of different radii: absorption, Rayleigh scattering, Mie scattering, and geometric optics. The atmospheric equation is a combination of modeling techniques covering the four cases. To render the interaction of light with the atmosphere, we present the rendering technique called volume tracing. Examples of blue sky, sunset, hazy sky, shaft of light beam, and rainbow are given.

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