ABSTRACT
In order to account for non-local shadowing effects, ray tracing resorts to splitting and166 additionally traces secondary rays that evaluate the transmittance between each primary intersection point and all point light sources [Appel, 1968], thereby resolving E(D|G)L paths,431 while specular surfaces may similarly be deterministically simulated by recursively tracing486 a reflection ray and a refraction ray, effectively generating a binary ray tree additionally capturing ES∗(D|G)L paths [Whitted, 1979, Whitted, 1980]. As illustrated in Figure 16.1,598 distribution ray tracing [Cook et al., 1984, Cook, 1989] further extends the approach to E(D|G|S)∗L paths (including direct illumination paths of the form E[D|G|S]L) by stochastically distributing the sampling rays over time, lens area, area light and about the specular429 surface reflection and refraction directions in order to also simulate motion blur, depth of field, penumbrae, gloss and translucency, respectively, in addition to resorting to jittered662 sampling over pixel area for anti-aliasing [Cook, 1986, Cook, 1988, Cook, 1989].
