In this tutorial, we discuss voxel DAGs and multiresolution hierarchies, which are representations that can encode large volumes of data very efficiently. Despite a significant compression ration, an advantage of these structures is that their content can be efficiently accessed in real-time. This property enables various applications. We begin the tutorial by introducing the concepts of sparsity and of coherency in voxel structures, and explain how a directed acyclic graph (DAG) can be used to represent voxel geometry in a form that exploits both aspects, while remaining usable in its compressed from for e.g. ray casting. In this context, we also discuss extensions that cover the time domain or consider an advanced encoding strategies exploiting symmetries and entropy. We then move on to voxel attributes, such as colors, and explain how to integrate such information with the voxel DAGs. We will provide implementation details and present methods for efficiently constructing the DAGs and also cover how to efficiently access the data structures with e.g. GPU-based ray tracers. The course will be rounded of with a segment on applications. We highlight a few examples and show their results. Pre-computed shadows are a special application, which will be covered in detail. In this context, we also explain how some of previous ideas contribute to multi-resolution hierarchies, which gives an outlook on the potential generality of the presented solutions.@en

This course provides an overview of efficient, real-time shadow algorithms. It presents the theoretical background but also discusses implementation details for facilitating efficient realizations (hard and soft shadows, volumetric shadows, reconstruction techniques). These elements are of relevance to both experts and practitioners. The course also reviews budget considerations and analyzes performance trade-offs, using examples from various AAA game titles and film previsualization tools. While physical accuracy can sometimes be replaced by plausible shadows, especially for games, film production requires more pecision, such as scalable solutions that can deal with highly detailed geometry. The course builds upon earlier SIGGRAPH courses as well as the recent book Real-Time Shadows (A K Peters, 2011) by four of the instructors (due to its success, a second edition is planned for 2014). And with two instructors who have worked on AAA game and movie titles, the course presents interesting behindthe-scenes information that illuminates key topics.@en