This paper demonstrates the use of cellular automata in the study of heat and mass transfer processes, in particular during wood drying. For study, we developed a three-dimensional mathematical model. This model is described by a system of interconnected differential equations. These equations are described in partial time derivatives and coordinates in space. The peculiarity of this work is the possibility of combining a three-dimensional mathematical model and the theory of cellular automata in solving the problem. Usage of the theory of cellular automata requires the presence of a certain number of identical elements of the system. In this case, we propose to present the studied CAD model in the form of cubes of the same size. The paper also describes the relationships between the created cubes. In addition, we give the algorithm of calculations. Based on the described algorithm, we carried out the number of experiments, which prove the possibility of using the theory of cellular automata in solving the problem.