The precise positioning even in very complex multi-product or multi-line plants can be achieved thanks to the availability of cheap simulation software and PC power for the analysis of the material flows. Whereas mathematical optimization methods for the projection of batch production are limited, simulation models that are specifically cut out for the task can make a very real projection of the complex procedures and goals in multi-product or multi-line plants. The use of object-oriented software for the specific simulation of the material flows in the optimization of a plant at the project funding stage is described.