Using suitable design media appropriately: Understanding how designers interact with sketching and CAD modelling in design processes

This paper investigates the roles of sketching and computer-aid-design modelling in mixed media design environments, and how switching behaviours could impact on them. Six designers participated in a protocol study in which their activities were video recorded. The recordings were coded using the Function-Behaviour-Structure coding scheme. Having completed their tasks, participants reviewed the recordings and were asked to explain their switching behaviours. A three-level coding scheme for analysing switching behaviours was adapted from relevant literature. The results show that both sketching and CAD modelling played a markedly similar role in the design process because the design media selected suited the designers' needs. Moreover, our proposed three types of switching behaviours supported designers in perception, media and concept levels during designing.