Fake Fur Rendering
Dan B Goldman, "Fake Fur Rendering", In
SIGGRAPH 97 Conference Proceedings, pp. 127-134., 1997.
Abstract
A probabilistic lighting model is presented for thin coats of fur over
skin. Previous methods for rendering furry objects and creatures have
addressed the case where individual strands or tufts of hair may be
resolvable at the pixel level. These methods are often compuationally
intensive. However, a large class of real-world cases where
individual hairs are much smaller than the size of a pixel can be
addressed using a probabilistic model for the expected value of
reflected light within a small surface area. Under the assumption
that hair parameters are slowly varying across the skin, lighting
calculations are performed on a reference hair with prefiltered
parameters. The reflected light from individual hairs and from the
skin below is blended using the expectation of a ray striking a hair
in that area as the opacity of hte fur coating. Approximations for
hair-to-hair shadowing and hair-to-skin shadowing can be made using
the same hit-expectation model. Our system can be implemented in
existing commercial surface-rendering software at a much lower
computation cost than typical resolvable-hair methods.
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