CIMOSA enterprise models provide a basis for documenting, operating, and redesigning a company. However, up to now CIMOSA is not commonly accepted in industries. This is mainly due to the fact that CIMOSA users do not know how to create their particular models efficiently. Currently, they are faced with the collection of a tremendous amount of data which makes the model creation process an unaffordable effort. This paper proposes a new bottom-up modelling methodology for the design of particular CIMOSA models: The modelling starts with the identification of the most important process according to a specific goal. This core model is then expanded from inside to outside by adding further processes which art: also relevant. With respect to the implementation of a corresponding modelling tool, the basic data structures for the model representation and the procedures which are needed to process them art: also shown. Finally, our modelling and simulation prototype tool, the Virtual Factory Lab Victor is introduced.