The challenge in the vehicle and supplier industry today is to produce economically despite highly volatile markets and under dynamic conditions. The decisive competitive factor here is the adaptability of production systems. In order to achieve maximum adaptability, a strict separation must be created between the hardware of the production systems and the controlling software. The SDM4FZI project therefore deals with the new method: software-defined manufacturing (SDM). Analogous to solutions from information and communication technology, non-predefined functions are also to be realised by automatically generated software. The basic prerequisite is the abstraction of the existing hardware through digital twins with the help of which the software can be automatically derived and distributed. For this purpose, the existing production OT (Operational Technology) must be rethought in order to make the control and communication infrastructure SDM-capable. SDM creates the basis for innovative applications and business models that use digital twins as their core to optimise adaptable production systems.