Most engineers nowadays receive a mono-disciplinary education: Mechanical engineering, Electrical engineering etc. Contradictory, the products they have to design are ever more multidisciplinary and integrated. This requires a different mindset. This paper discusses four tools that fit in the engineers’ toolkit to approach these multidisciplinary problems: TRIZ, Systematic Inventive Thinking, Quality Function Deployment and FunKey Architecting. The tools are discussed and rated on four scales: difficulty of problems, complexity of problems, design phase and learning effort. From the characterization a set of heuristics is derived that help in choosing the appropriate tool from the toolkit. It is concluded that the four tools largely complement each other and should therefore be part of every engineer's toolkit.