| Abstract | To render an object by ray tracing, one or more rays are shot from the viewpoint through every pixel ofthe image plane. For reflective and refractive objects, especially for multiple levels of reflections and/or
refractions, this requires many expensive intersection calculations. This paper presents a new method for
accelerating ray-tracing of reflective and refractive objects by substituting accurate-but-slow intersection
calculations with approximate-but-fast interpolation computations. Our approach is based on modeling the
reflective/refractive object as a function that maps input rays entering the object to output rays exiting the
object. We are interested in computing the output ray without actually tracing the input ray through the
object. This is achieved by adaptively sampling rays from multiple viewpoints in various directions, as a
preprocessing phase, and then interpolating the collection of nearby samples to compute an approximate
output ray for any input ray. In most cases, object boundaries and other discontinuities are handled by ap-
plying various heuristics. In cases where we cannot find sufficient evidence to interpolate, we perform ray
tracing as a last resort. We provide performance studies to demonstrate the efficiency of this method.
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