A method to investigate differences of sketching before and during CAD modelling design process.

Previous research, such as Sachse et al’s, adopted traditional sketching in the CAD modelling process and this method improved the design quality. However, there has been little investigated from a cognitive perspective of using mixed media. Mixed media design environments consist of conventional and digital tools, which are often superior to an individual tool during the conceptual design phase. When designers switch media from sketching to CAD modelling, the action of shifting is believed to improve design creativity. In studies of mixed media, designers were asked to use sketching first followed by CAD modelling. This method of using mixed media involving one shift in media is called sequential mixed media (SMM). However, there is an alternative method of using mixed media, known as alternate mixed media (AMM), in which designers alternate freely between sketching and CAD modelling. There has been limited studies in exploring designers’ behaviours in AMM, their shifting actions between tools and the triggering factors initiating the shifting actions. The paper provides a comprehensive analysis of a wide variety of design tools supporting conceptual design in the early design process. The paper also presents a methodology for a future study to investigate design cognition in mixed media design environments. The outcomes of the proposed research will lead to a more critical understanding of the way of using both design tools so that they can be utilised more effectively. The proposed research will particularly answer why and when designers shift from one tool to another tool during the conceptual design phase