Within this paper, we present a practical approach to generate and simulate coupled models for switching domains in material sciences, for example in crystal structures of ferroelectric materials or magnetic shape memory alloys (MSMA). Instead of developing combined averaged FE-models, we propose an approach by augmenting existing mechanical and electromagnetic FE-code. The necessary domain variables and inequalities are described and the implementation in COMSOL Multiphysics by smoothing the discontinuities is shown for MSMA. The simulation results are compared with experimental data and remaining deviations are discussed. The individual strengths and weaknesses of our approach compared to averaged models result in different use cases.