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 risk.
Figure 1.3. Time2Teach: virtual reality tool for quickly and simply creating video animations, 3D or virtual environments to illustrate, for example, a mechanical operation, and also to create visual representations of flows (here, for example, air flows). For a color version of this figure, see www.iste.co.uk/fleury/innovation.zip
It is commonly accepted and widely demonstrated that drawing by hand, with or without digital media, is more conducive to the discovery of new concepts than working with a keyboard and mouse (see, for example, Ibrahim and Rahimian 2010; Jackson and Keefe 2016). In our team, we conducted a large study that investigated both the creativity associated with different sketching tools and the communicability of the ideas generated by these tools, that is,
