A Rendering Algorithm for Discrete Volume Density Objects

: We present a new algorithm for simulating the effect of light travelling through volume objects. Such objects (haze, fog, clouds...) are usually modelized by voxel grids which define their density distribution in a discrete tridimensional space. The method we propose is a two-pass Monte-Carlo ray-tracing algorithm that does not make any restrictive assumptions neither about the characteristics of the objects (both arbitrary density distributions and phase functions are allowed) nor about the physical phenomena included in the rendering process (multiple scattering is accounted for). The driving idea of the algorithm is to use the phase function for Monte-Carlo sampling, in order to modify the direction of the ray during scattering. Keywords : Monte-Carlo Ray-Tracing, Participating Media, Volume Density Objects, Multiple Scattering. 1 Introduction Rendering methods of objects defined by their density distribution in a tridimensional space can be divided in view-dependent and view-i..