The authors developed a microparticle simulation for low-pressure plasma environments occurring in certain plasma coating systems. The simulation is based on a theoretical model for the forces and currents acting on microparticles and takes place in a 3D geometry modeled after the coating chamber. As a test case, the Enhanded Optical Sputtering System was used, and the resulting size distribution functions for two different microparticle species were compared with experimental size distributions, showing a qualitative agreement and yielding some explanations for the experimental results.