Proceedings of the Industrial Simulation Conference 2004, 88-93 Granular systems appear in many industrial and agricultural disciplines, which has lead to a wide range of models for their simulation, both in engineering and applied physics. However, most of the current models are addressed to make a deep analysis of the properties of the system, and they are not suitable for their use in real-time simulations. Thus, despite of the efforts in computational fluid dynamics and molecular dynamics, the application of granular systems in the field of virtual reality and computer graphics lacks of a set of fast interactive models that allow their execution in real-time. In this paper we propose an efficient granular system model based on cellular automata, designed to be used in computer graphics applications. The model is provided with inertia which gives it more realistic physical properties. Also, several details for its implementation are given together with an analysis of its computational complexity.