This paper demonstrates how an existing game technology as a component off-the-shelf can be used as a basis to build a serious game for assistive technology for disabled people.Using the example of a virtual electric wheelchair simulator, we present how to use a computer game physics engine to achieve a realistic simulation of driving an electric wheelchair in a virtual environment. Focus of the paper is the conversion of driving characteristics of prevalently used electric wheelchairs into the virtual physics system of the used computer game engine. The used parameters are systematically balanced between the virtual and the real world to evaluate the realism of the driving characteristics of an electric wheelchair using the integrated physics simulation of the Unreal Engine 3.