Ignoring the Inconvenient When Tracing Rays

Ray tracing’s greatest strength—that it can simulate all types of light transport—can also be its greatest weakness: when there are a few paths that unexpectedly carry much more light than others, the produced images contain a smattering of pixels that have bright spiky noise. Not only can it require a prohibitive number of additional rays to average out those spikes, but those pixels present a challenge for denoising algorithms. This chapter presents two techniques to address this problem, preventing it from occurring in the first place.