Abstract
In this paper we describe an algorithm to render the asterism or chatoyancy effect in gems. This effect is due to light dispersion caused by inclusions consisting of vast numbers of thin fibrous needles. We develop models for distribution of the microfacet directions of the inclusions and of the light dispersion by them. Based on these models we derive an algorithm to render gems with the asterism effect. By introducting a ray distribution map, a new algorithm for tracing dispersed light rays is developed.
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Yokoi, S., Kurashige, K. & Toriwaki, Ji. Rendering gems with aterism or chatoyancy. The Visual Computer 2, 307–312 (1986). https://doi.org/10.1007/BF02020431
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DOI: https://doi.org/10.1007/BF02020431