This paper addresses the question of how Modular Design methods can support the development of complex products. The goal of selected Modular Design methods is to improve transparency in the development of modular systems to be able to structure these systems in a way that adds value to the observed company and to derive optimized product architectures from the conducted procedures. The problem addressed here is that existing methods can develop increasingly less transparency within the development of complex products, since the extent of these products rises increasingly. This increases the complexity of the work steps and scope of work, which results in a reduction of the immediate transparency in observing the underlying product architecture. To address this pain points, two selected methods in the context of Modular Design are exemplary adapted to agile approaches and principles. These adaptations are applied to two underlying case studies, each of which has to do with the development of complex products in various aspects. In the case studies, different process perspectives are depicted, which offer both a development process (further development of an existing system) of a laser cutting machine tool of a mechanical engineering company, as well as a development project (new design of a system with a high degree of novel development) of a smart industrial valve of a medium-sized engineering manufacturer with, in addition, an unknown proportion of new development as an investigation environment. The results show the integration of agile aspects in selected Modular Design methods as a successful support in generating transparency in the development of complex products and systems, in different process perspectives. At the same time, the research also shows that adaptations to the studied methods are necessary, such as continuous and centralized concept documentation, to apply them in an agile context.
