Fasim_C++ — A versatile developing environment for vehicle dynamics simulation. Modern vehicle controllers are becoming increasingly complex, making a pre-design based on comprehensive vehicle dynamics simulation necessary. FASIM_C++ contains an object-oriented model library providing mathematical models for particular vehicle types with different topologies like motor cars and trucks with and without trailers. Generally, the object-oriented design allows to extend the standard model of a vehicle with new modules in an easy manner. As an example, different impact models can be adapted to several vehicle modules, e.g. the tyres, wheel suspensions or the vehicle body. The model of the environment can be extended from models for normal road conditions to e.g. off-road models with different topographies.