A statistical multi-lobe approach was recently introduced in order to efficiently handle layered materials rendering as an alternative to expensive general-purpose approaches. However, this approach poorly supports scattering volumes as the method does not account for back-scattering and resorts to single scattering approximations. In this paper, we address these limitations with an efficient solution based upon a transfer matrix approach which leverages the properties of the Henyey-Greenstein phase function. Under this formalism, each scattering component of the stack is described through a lightweight matrix, layering operations are reduced to simple matrix products and the statistics of each BSDF lobe accounting for multiple scattering effects are obtained through matrix operators. Based on this representation, we leverage the versatility of the transfer matrix approach to efficiently handle forward and backward scattering which occurs in arbitrary layered materials. The resulting model enables the reproduction of a wide range of layered structures embedding scattering volumes of arbitrary depth, in constant computation time and with low variance.

Summary This paper describes the use of domain decomposition methods for accelerating wave physics simulation. Numerical wave‐based methods provide more accurate simulation than geometrical methods, but at a higher computation cost as well. In the context of virtual reality, the quality of the results is estimated according to human perception, what makes geometrical methods an interesting approach for achieving real‐time physically‐based rendering. Here, we investigate a geometrical method based on both beams and rays tracing, which we enhance by two levels of parallel processing. Techniques from domain decomposition methods are coupled with classical parallel computing on both shared and distributed memory. Both optic and acoustic renderings are experimented to evaluate the acceleration impact of the domain decomposition scheme. Speedup measurements clearly show the efficiency of using domain decomposition methods for real‐time simulation of wave physics. Copyright © 2015 John Wiley & Sons, Ltd.

Abstract This article discusses the important problem of determining pertinent data to describe a pigmented medium. The first part deals with optical characteristics of pigments and the general properties of binders and fillers. It also exposes the limits and conditions of applicability of single scattering. In the second part the connection between individual optical properties, size, and form of particles is made with phenomenological theories of multiple scattering in absorbing media, Progressively, it appears that pertinent data in realistic modelling are always in relation with true or effective complex refractive indices and size parameters.