Recently, Cu(In, Ga)Se-2 (CIGS) technology made a big step from research and development to fabrication. Mass production of high performance and high quality photovoltaic modules requires the scale up of in-line CIGS co-deposition processes to large areas. An important step towards larger areas was the installation of an in-line deposition system for 30 x 30 cm(2) modules at ZSW. To support the design of the process, we developed software based on the finite element method (FEM) to model and optimise the elemental flux distributions of evaporation sources. This method is presented and applied to the ZSW large area deposition. Excellent agreement of simulation and experimental data is found. We simulate CIGS growth conditions and discuss device results.