A method for simulating an epitaxial process in a body having a crystal lattice structure. Roughly described, an enlarged version of the crystal lattice structure is formed, having a lattice constant increased by a lattice enlargement factor N>1. The subject fabrication process is simulated by a Lattice Kinetic Monte Carlo algorithm in which various factors have been scaled in accordance with N. The simulation speed increases by a factor around N3, without significantly degrading the accuracy of the resulting simulated structure. The simulated epitaxial process can later be performed on a physical crystalline body.