LITTERATURE/EXPERTISE REVIEW
THE IMPORTANCE OF FREEHAND SKETCHING /RAPID VISUALIZATION IN DESIGN ACTIVITIES
The behavior of sketching could be considered as a key factor in stimulating and developing design creativity. I interested in finding out the process of design thinking by the analysis of sketches at the early design stage. This research aimed to confirm the importance of sketching at the conceptual design stage and to explore an appropriate method to improve the efficiency of ideation.
Keyword: design thinking, sketch, conceptual design

Sketching in conceptual design
During the conceptual stages of design, sketch is used widely to express ideas and has been deemed as the medium of reflection-in-action. Sketches are representations that allow designers to try out new ideas on paper quickly and economically. In addition, the sketch possesses the potential to act as both facilitator and recorder of creative acts, presenting opportunities for improved evaluation and the restating of problems [Temple, 1994]. Ferguson identifies three kinds of sketch, namely the thinking sketch, the prescriptive sketch, and the talking sketch [Ferguson, 1992]. The thinking sketch is used to focus and guide non-verbal thinking. Sketch is made by a designer to direct a draftsman in making a finished drawing. Finally, the talking sketch is produced through the exchanges between designers and engineers while clarifying complex and possibly confusing parts of a drawing. However, the ability of the sketch is to communicate design proposals with others.
The argument given by Cross (1990), provides a strong supporting role to that of the `Design Process' theory advocated by Schön (1990) and allows essential constructs like `geometric reasoning'; `three-dimensional problem-solving'; `visual-spatial thinking'; `naive-designers way of thinking'; `conjectured-solutions' or `ability to generate alternative solution'; `thinking with a pencil' as in the importance of sketches