We’re humbled and delighted by the excitement and interest that our rollout of Ray Tracing Gems has generated! It was a labor of love to write, and we can’t wait to see how it influences the development community. Part IV of Ray Tracing Gems is now available for FREE on  NVIDIA Developer Zone. In this installment, the focus is on sampling.

Here is the forward for Part IV, written by Alexander Keller, director of research at NVIDIA:

“Ray tracing is all about sampling, and sampling is the basic operation of computing averages. Similarly to conducting a survey, it is important whom you ask, as this determines how reliable your statistics will be.

Chapter 15, “On the Importance of Sampling,” takes you on a tour through some useful integrals in graphics that are computed by averaging. You will learn why sampling matters, how variance decreases and may be decreased, and why a denoiser is becoming inevitable.

The journey then takes you to Chapter 16, the “Sampling Transformations Zoo.” We will walk you through a collection of useful code snippets that let you transform uniformly distributed samples according to a desired density or onto a piece of geometry. It is the perfect complement for all the sampling tasks that you need to complete when crafting your own rendering algorithm based on ray tracing.

Not everything turns out nice with sampling. And in fact, Chapter 17, “Ignoring the Inconvenient When Tracing Rays,” will help you very much understand what can go wrong with sampling. There is a simple way for you to fix things, and a second alternative that at least does not destroy all rendering mathematics. All in all, this chapter provides crucial and battle-proven insight.

As an example of how to put things together, Chapter 18, “Importance Sampling of Many Lights on the GPU,” provides a fast implementation of a modern algorithm to deal with illumination by many lights. This has been a classic challenge in rendering movies that now enters the domain of real-time image synthesis. This chapter is an excellent starting point for your own development.

There is so much more to learn about sampling. Do not forget to check out the references to Monte Carlo and quasi-Monte Carlo integration in these sampling chapters!”

DOWNLOAD RAY TRACING GEMS PARTS I, II, III, and IV HERE: NVIDIA Developer Zone.