Monte Carlo methods for volumetric light transport simulation

The wide adoption of path-tracing algorithms in high-end realistic rendering has stimulated many diverse research initiatives. In this paper we present a coherent survey of methods that utilize Monte Carlo integration for estimating light transport in scenes containing participating media. Our work complements the volume-rendering state-of-the-art report by Cerezo et al. [2005]; we review publications accumulated since its publication over a decade ago, and include earlier methods that are key for building light transport paths in a stochastic manner. We begin by describing analog and non-analog procedures for free-path sampling and discuss various expected-value, collision, and track-length estimators for computing transmittance. We then review the various rendering algorithms that employ these as building blocks for path sampling. Special attention is devoted to null-collision methods that utilize fictitious matter to handle spatially varying densities; we import two “next-flight” estimators originally developed in nuclear sciences. Whenever possible, we draw connections between image-synthesis techniques and methods from particle physics and neutron transport to provide the reader with a broader context.

• paper (PDF, 7.2 MB)
• citation (BIB)
• 1 Introduction – slides by Wojciech (PDF, 10 MB)
• 2 Fundamentals – slides by Jan (PDF, 3.1 MB)
• 3 Distance sampling – slides by Jan (PDF, 19 MB)
• 4.1 Transmittance estimation – slides by Wojciech (PDF, 6.6 MB)
• 4.2 Transmittance estimation using null collisions – slides by Jan (PDF, 3.7 MB)
• 5 Path construction – slides by Iliyan (PDF, 7.8 MB)
• 6.1 Advanced methods – slides by Wojciech (PDF, 12 MB)
• 6.2 Advanced methods & acceleration data structures – slides by Johannes (PDF, 4.9 MB)