Interplay of Sketches and Mental Imagery in the Design Ideation Stage of Novice Designers

This paper seeks to understand the interplay between the acts of pen-and-paper-based sketching and the use of mental imagery. A protocol study of four novice designers was conducted in two different environments: with access to sketches only; and blindfolded and delayed sketches. In total there were eight 45 minute design sessions. This study confirms that sketches and mental imagery support ideation stages in unique ways and both are equally germane. Identified interplaying roles when only sketches are utilized are: supporting, co-evolving, and reflecting roles. In addition, interplay can happen at the exact moment or distantly; and the order of an interplay depends on the designers' strategy. In sessions where sketches are for externalizing design proposals only at the end, identified roles are: generative and provocative to idea exploration. It is also observed that gesture does not compensate for the absence of external representation, although it conveys important design messages.