Abstract

As most engineering design proceeds by modifying past designs and reusing and adapting existing components and solution principles, a significant part of the knowledge engineers employ in design is encapsulated in the past designs they are familiar with. References to past designs, as well as encounters with them, serve to invoke the knowledge associated with them and constructed from them. This chapter argues that much of this knowledge is tacit consisting in and/or made available by the perceptual recognition of features and situations, using a discussion of design margins to illustrate how engineers use tacit knowledge in reasoning about the properties of new designs.