Combine harvesters are key machines in agricultural harvesting, yet their use is limited to a few weeks each year for most customers. This limitation highlights the need to develop machines that are user-friendly and intuitive to use for operators at different skill and experience levels. In response, an interactive combine harvester simulator is being investigated that incorporates the knowledge of different stakeholders in the development process of new machines. The scenarios of the simulator are based on the analysis of typical key situations frequently encountered by operators. The development of the simulator involves the use of real HMI components and follows the E&E architecture found on the real machine. Combination of real HMI hardware as well as simulation models for individual components and subsystems enable the use at earlier stages of the product development cycles. Realistic combine behavior in different harvesting situations is simulated by a process model based on the material flow in the machine, also taking into account crop properties and variable field characteristics. The simulator is to be used in the customer-focused development of new machines as well as for operator training and research, allowing new machine features and procedures to be tested all year round.