This paper presents a new sampling strategy to achieve interactive global illumination on one commodity computer. The goal is to propose an efficient numerical stochastic scheme which can be well adapted to a fast rendering algorithm. As we want to provide an efficient sampling strategy to handle difficult settings without sacrificing performance in common cases, we developed an extension of Instant Radiosity [Kel97] in the same way bidirectional path tracing is an extension of path or light tracing. Our idea is to build several estimators and to efficiently combine them to find a set of virtual point light sources which are relevant for the areas of the scene seen by the camera. The resulting algorithm is faster than classical solutions to global illumination. Using today graphics hardware, an interactive frame rate and the convergence of the scheme can be easily obtained in scenes with many light sources, glossy materials or difficult visibility problems.

Global illumination dramatically improves realistic appearance of rendered scenes, but usually it is neglected in VR systems due to its high costs. In this work we present an efficient global illumination solution specifically tailored for those CAVE applications, which require an immediate response for dynamic light changes and allow for free motion of the observer, but involve scenes with static geometry. As an application example we choose the car interior modeling under free driving conditions. We illuminate the car using dynamically changing High Dynamic Range (HDR) environment maps and use the Precomputed Radiance Transfer (PRT) method for the global illumination computation. We leverage the PRT method to handle scenes with non-trivial topology represented by complex meshes. Also, we propose a hybrid of PRT and final gathering approach for high-quality rendering of objects with complex Bi-directional Reflectance Distribution Function (BRDF). We use this method for predictive rendering of the navigation LCD panel based on its measured BRDF. Since the global illumination computation leads to HDR images we propose a tone mapping algorithm tailored specifically for the CAVE. We employ head tracking to identify the observed screen region and derive for it proper luminance adaptation conditions, which are then used for tone mapping on all walls in the CAVE. We distribute our global illumination and tone mapping computation on all CPUs and GPUs available in the CAVE, which enables us to achieve interactive performance even for the costly final gathering approach.

Ray tracing and photon mapping provide a practical way of efficiently simulating global illumination including interreflections, caustics, color bleeding, participating media and subsurface scattering in scenes with complicated geometry and advanced material models. This halfday course will provide the insight necessary to efficiently implement and use ray tracing and photon mapping to simulate global illumination in complex scenes. The presentation will cover the fundamentals of ray tracing and photon mapping including efficient techniques and data-structures for managing large numbers of rays and photons. In addition, we will describe how to integrate the information from the photon maps in shading algorithms to render global illumination effects such as caustics, color bleeding, participating media, subsurface scattering, and motion blur. Finally, we will describe recent advances for dealing with highly complex movie scenes as well as recent work on realtime ray tracing and photon mapping. About the Lecturers