Efficient Free Path Sampling in Inhomogeneous Media

László Szirmay-Kalos, Balázs Tóth, Milán Magdics, and Balázs Csébfalvi
Department of Control Engineering and Information Technology, Budapest University of Technology and Economics,
Budapest, Magyar Tudósok krt. 2, HUNGARY


This paper presents an efficient algorithm to sample free path in inhomogeneous participating media. The method is based on the concept of mixing ``virtual'' particles to the medium, that complete the extinction coefficient to a piece-wise constant function. We use the sampling formulae developed for piece-wise homogeneous medium, but decide randomly whether a real or a virtual particle is hit.


Inhomogeneous media, Free path sampling, Woodcock tracking, CUDA, Real-time multiple scattering simulation.