User experience is an eminent part of holistic product design. Especially in the field of mobile machinery, the driver’s impression of the machine handling is crucial for successful design. To get an early understanding of the ergonomic aspects of a new concept of operation, functional prototypes can be applied. This paper presents the tools to develop a functional prototype using free software and low-cost hardware. This includes prototyping of control devices, interfaces to the Modelica-based simulation models and a generic visualization using a game engine. In order to speed up the process of functional prototyping,
an approach to automatically visualizing FMUs based on a scene description file is presented. The application of interactive simulation was used to support the development of a novel control device for excavators in a student project at TU Dresden