Path tracing in production: part 1: modern path tracing

In the past few years the movie industry has switched over from stochastic rasterisation approaches to using physically based light transport simulation: path tracing in production has become ubiquitous across studios. The new approach came with undisputed advantages such as consistent lighting, progressive previews, and fresh code bases. But also abandoning 30 years of experience meant some hard cuts affecting all stages such as lighting, look development, geometric modelling, scene description formats, the way we schedule for multi-threading, just to name a few. This means there is a rich set of people involved and as an expert in either one of these aspects it is easy to lose track of the big picture. This is part I of a full-day course, and it focuses on the necessary background knowledge. In this part, we would like to provide context for everybody interested in understanding the challenges behind writing renderers intended for movie production work. In particular we will give an insight into movie production requirements for new students and academic researchers. On the other side we will lay a solid mathematical foundation to develop new ideas to solve problems in this context. To further illustrate, part II of the course will focus on materials (acquisition and production requirements) and showcase practical efforts by prominent professionals in the field, pointing out unexpected challenges encountered in new shows and unsolved problems as well as room for future work wherever appropriate.