the important concepts, in order to interact with their own mental representations. They will be in continuous interaction with their representations to make design decisions (Visser 2006). The process thus consists of alternating actions and judgments. The designer’s actions can produce unexpected results; the feedback is likely to suggest concepts. Tools that encourage spontaneity, that is, natural gestures and letting go, are the most likely to generate feedback
1.4.2. Types of representation
Reflective conversation will generally be more important in the early stages of design. Goel (1995) describes the design process as an evolution of different types of representations. For each stage, a particular type of representation is used for specific tasks. During the ideation stage, a first type of representation consisting of freehand sketches or physical models is mobilized to externalize and visualize design intentions or to communicate them with others. These first representations are what Goldschmidt (1992) calls idea-sketches. Later in the process, presentation sketches appear, in the form of digital 3D models, drawings or images, to improve communicating asynchronously with colleagues and clients about the proposals. At the end of the process appear the representations composed of detailed technical drawings and rapid prototyping models to communicate the exact and definitive information to build the product. During these three successive steps, the representations are likely to be mobilized during synchronous, but especially asynchronous collaborations with other designers or customers. For example, team ideation requires cognitive artifacts adapted to different visualization capacities, and these artifacts must also be manipulated in an intuitive way.
The design process is based on the creation of different forms of representations (Goel 1995). It is an iterative process in which designers propose and analyze forms to achieve identified functions. The generation of these forms depends on the designers’ abilities to create internal, mental and external visualizations (Cross and Roy 1989). Drawing is thus a key function of design, and the role of this activity evolves throughout the process. Drawing allows the designer to transform ideas into concepts, thus conceptualizing (Cross and Roy 1989; Ullman et al. 1990), to make these concepts communicable, and then to specify technical details (Bertoline 1999). Sketching allows designers to change their level of abstraction, expand their short-term memory to facilitate problem solving (Ullman 2003) and improve their exploration processes that are essential to understanding (Cross 1999).
The traditional engineering approach is to consider the drawing on paper as a draft that will be followed by work on a Computer-Aided Design (CAD) tool. However, there are certain restrictions imposed by CAD tools that, in the early stages of design, will hinder creativity, especially by generating fixation. The importance of sketching as a means of supporting visual reasoning was first highlighted in 1980 by McKim, who spoke of idea-sketching. Indeed, the designer’s conceptualization activity is limited, in particular, by his or her memory capacities. On average, short-term memory is limited to seven chunks of information (Miller 1956). In the case of the design of a technical object, a chunk
1.4.3. Conditions for the effectiveness of sketches
Sketches in a design project, to be effective, must possess a number of characteristics identified by Buxton (2007):
– quick to achieve, so as not to interfere with the creative process;
– done at the right time, sketches are useful when a designer needs to externalize a mental representation, for a reflective conversation, or to communicate their ideas, preferably in the upstream phases of design;
– inexpensive, because it is a matter of allowing for mistakes, corrections, changes of ideas, adjustments;
– disposable, the investment in a sketch is the concept and not the sketch itself (normally, several sketches are made quickly and all of them are kept, which implies that one should never find a sketch by itself);
– understandable, because the communicability of the idea depends on it;
– characterized by the freedom of the gesture, neither tightened nor too precise;
– minimalist, only what is important to the concept, because technical details are distractors that tend to interfere with the ideation work (Rodgers et al. 2000);
– with the appropriate degree of development; the sketch’s degree of development should match the idea’s degree of development so that designers are not fixated on details of the idea rather than its central features;
– suggesting rather than telling, because the sketch is not the technical specification document that appears much later in CAD; suggesting leaves the user of the sketch a share of deductions to make, which may be conducive to finding solutions;
– intentionally ambiguous, as one should not, in seeking to represent a specific concept on an object, fix all of the other characteristics of that object. It is better to remain ambiguous about those features of the object that are not central to this sketch (Tseng and Ball 2011).
1.4.4. The phases of ideation
Dorta’s (2004) and Goldschmidt’s (1992) work highlights two main phases in ideation, corresponding to different constraints: the reflection-in-action phase, during which the designer needs tools that allow him or her to represent his or her ideas quickly and with natural gestures, even if this leads to a very imprecise result. For this purpose, the traditional tools used are paper and pencils, whether in the form of Post-it notes, flip charts
Figure 1.2. Model of the upstream phase of design based on Dorta’s (2004) phases and Goldschmidt’s (1992) categories of sketches. For a color version of this figure, see www.iste.co.uk/fleury/innovation.zip
1.4.5. The right tools at the right time
Robertson and Radcliffe (2009) have highlighted risks associated with using CAD software too early in the design process. It will tend to circumscribe thinking, create early fixation or “bounded” ideation. With CAD software, the designer does not want to back out of an idea because it involves relatively heavy technical actions. In other words, CAD can become an “innovation killer” if it is used too early and designers must be trained in terms of method to avoid this