We explore the interpretation of drawings by analogy, and specifically the interpretation of drawings of a design. Given a drawing of an as-yet unknown device, a representation of the shapes and spatial relations in the drawing can be structurally aligned with that of a drawing of a known device, and if they are sufficiently similar, a structural model of that device transferred to the new drawing. This provides not only an identification of what that drawing is of, but also assigns particular roles to each shape in terms of the structure, the causality and behavior, and the function of the device. This process of analogical mapping and transfer is, in general, very hard, and can be guided by the use of functional knowledge. The structural model is part of a structure-behavior-function (SBF) model of the source that is already known. The Archytas system implements this analogical method.