Virtual prototyping and numerical simulations are increasingly replacing real mock-ups and experiments in industrial product development. Many of these simulations, e.g. for the purpose of crash worthiness explorations, are based on Finite Element Analysis (FEA). In order to accelerate the development cycle, simulation engineers want to be able to modify their FE models without going back to the CAD department and without remeshing. Currently, there are no intuitive tools available that offer the possibility of modification and processing of FE components while maintaining the properties relevant to the simulation. In this paper we present interactive algorithms for intuitive, fast, and robust editing of FE models and appropriate visualization techniques to support engineers in understanding these models. New kinds of manipulators and feedback mechanisms enable easy manipulation of FE models. To ensure a good quality of the deformed mesh we use relaxation extended by algorithms prese...