The ability to design and manufacture highly customer adapted products brings a competitive edge to manufacturing companies acting on a business-to-business market as suppliers to OEMs. A vital means for success in quotation and order preparation is advanced system support in design, process planning and cost estimation based upon the automation of engineering tasks. A design automation system encapsulates these tasks which are to be executed for specific customer specifications in a sequence specified either by a predefined order or resolved by an inference mechanism in run-time. Commonly, the development of a design automation system is an iterative process alternating between a top-down and a bottom-up approaches. An overall strategy is a necessity for successful system development, however, to successfully define the tasks, retrace all the necessary knowledge and to close gaps in both the tasks and the knowledge definitions require a complete and detailed understanding of the specific domain. In this paper, the concept of Knowledge Object is described together with examples of its use in both the development and system realization of design automation systems enabling product customization. The concept has shown to be useful for modelling of design processes, tasks, and engineering knowledge as well as in system development and realization. It also supports traceability and understanding by relations to other concepts describing associated requirements and design rational.