A new methodology and code for 3-D radiation of nongray gases mixtures containing gray anisotropically scattering particles is developed. Radiative transfer equation (RTE) is solved by finite volume method (FVM) coupled with Smith's weighted sum of gray gases model (WSGGM) with 5 gray gases, but any other gas radiative properties model can be incorporated. Evaluation of scattering phase function (SPF) and analysis of anisotropically scattering particles were performed by Mie Theory (MT). Missing benchmark, another new 3-D model and code, which solve same problems, based on a combination of Zone Method (ZM) and Monte Carlo method (MC) is developed. In this method the same WSGGM and MT, as in previous methodology, is incorporated. Physical and mathematical concepts of both models are presented. To author's best knowledge these methodologies were not developed before. Series of predictions for the mixtures of real gases as carbon dioxide, water vapor and nitrogen containing various types of particles for non-uniform temperature field were performed by both methods in order to be compared. Agreement between the predictions of these two different numerical methods is very good. Model developed is sufficiently accurate and convenient for engineering calculations as well as for incorporation in computational fluid dynamics codes. (C) 2013 Elsevier Ltd. All rights reserved.