The use of Virtual Twins in HiL and SiL environments, especially in FCCU calibration, is the ultimate Turing test for the underlying model. It requires highest accuracy, robustness and computational performance with hard real-time capability. At AVL, our simulation software is developed by engineers for engineers. The software is used in development departments to create Virtual Twins to efficiently support the development process. This webinar will provide insight into various aspects of both simulation software development and engineering for fuel cell systems, highlighting the mutual benefits of the two disciplines under one roof.