Design Constraints Adopted by Designers for Concept Design

Abstract

In the area of product design, different stakeholders communicate each other through design constraints. This paper reports how designers use different constraints in sketch phase. Senior students in industrial design major participated in the experiment and their idea sketches and verbal data were collected. The data was categorized with a coding scheme developed from Lawson’s design problem model. Through the experiment, three major findings were proposed. First, unlike architects, product designers not only consider ‘designer constraints’, but also other generators’ constraints in sketch phase. Second, constraints related to interaction between users and the object mostly fall into external constraints, because most user interactions in products are occurred on the surface of the product. Last, fewer constraints in client and legislator categories are adopted while a large number of constraints of user category are used by designers in the ideas sketch phase. Based on these insights and analysis, this paper indicates that Lawson’s model needs to adopt the nature of product design and process which are different from architecture to be appropriately applied into product design development.