The goal of many intelligent computer aided design systems, and in particular knowledge based systems, is to provide advice in the form of critiques, relevant cases or examples, and the results of simulations. How can these systems decide when and what advice to provide the designer? Specifically, can intelligent design systems determine what advice to give
designers by looking at their drawing? The drawing conventions that designers share in designing may be a good indication of what contexts and concerns they are interested at the time. If so, this raises the question: what drawing conventions should a computer understand?