Agile production needs a management and evaluation tool for production changes, manufacturing system development, configuration and operations planning. A decision support system based on manufacturing simulation is one suitable solution. The basic idea is to combine the strengths of automatic data analysis, calculations, simulation results with the visual perception and analysis capabilities of the human user, who is doing final decisions. The use of simulation with an easy-to-use graphical user interface provides tools and methods for manufacturing scenario evaluation, scheduling optimization, and production planning even for simulation non-experts. This article shows a user-centric development process for those systems.