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 corresponds to a characteristic of the product. Technical experts in this product category are then able to put more information in each chunk than novices (Ullman 2003). The quick sketch, the idea-sketch, is a way to externalize these chunks, making these sketches an extension of short-term memory. Thus, improving sketching skills, or improving the sketching tool, will help to store more information through these visualizations and will thus reduce the duration of the ideation phase.

      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):

      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 or notepads. As we will detail later, virtual reality tools such as Time2Sketch are particularly well suited to this phase since they allow freehand 3D drawings to be made quickly and easily in the appropriate virtual environment. The second phase concerns the asynchronous collaboration, and implies that the designer realizes one or several “presentation sketches”, that is, more precise and communicable representations of their ideas. This phase is usually done with CAD software. However, among virtual reality tools, software such as Time2Teach – enabling 3D animations to be created quickly using integrating flows – and Time2Craft – a virtual reality CAD module – enable this design step to be accelerated.