Abstract: When engineering complex systems, a broad range of information and knowledge needs to be applied. Rather than capturing all this information and knowledge in text-based documents as used to be common practice in traditional systems engineering approaches, Model-Based Systems Engineering advocates capturing knowledge in models. Modeling in this context should be interpreted broadly, encompassing all information and knowledge used for systems engineering: requirements, functions, logical and physical components, logical and physical behavior, etc. In this presentation, I will provide an overview of capturing knowledge in the Systems Modeling Language (OMG SysML) augmented with domain specific models. Examples focus on the capture and use of synthesis and analysis knowledge for hydraulic systems design.