  The ongoing digital transformation in industry applies to all product life
cycle's stages. The design decisions and dimensioning carried out in the early
conceptual design stages determine a huge part of the product's life cycle
costs (LCC). The automation of the conceptual design phase promises therefore
huge gains in terms of LCC. Design grammars encode design processes in
production systems made up of rule sequences which automatically create an
abstract central product model (central data model) from given requirements.
Graph-based design languages use the Unified-Modeling-Language (UML) to define
the product entities (classes) supporting object-oriented inheritance.
Graphical rules instantiate the classes and iteratively assemble the central
model. This paper proposes to extend the design languages by introducing
methods (operations). This allows the use of object-oriented design patterns
and interface mechanisms as object-oriented principles are then fully
implemented. A graphical mechanism to model the method calls is presented which
integrates seamlessly into the graph-based design language's graphical rule
specification. The object oriented design grammar enables modularization and
reusability of engineering knowledge. The integration of engineering domains is
enhanced and multistakeholder collaboration with access control (information
security) becomes feasible.
