The use of conventional ergonomic designing aids necessitate a large experimental phase and a lot of iteration steps. Extensive tests are required by two reasons: The ergonomic design aids are not able to represent the morphology of real persons among the population. Furthermore it is very difficult to estimate, based on a CAD dataset, a real persons reaction in the designed environment. To overcome these deficiencies an man model (RAMSIS) in CAD with a large anthropometric database is used. A fast representation of a CAD dataset in a practical environment is realized by an computer controlled variable car mock-up.