Szirmay-Kalos, LászlóTóth, BalázsMagdics, MilánCsébfalvi, BalázsAnders Hast and Ivan Viola2015-07-082015-07-082010https://doi.org/10.2312/egp.20101020This 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.10.2312/egp.20101020