A Study of Usability of Sketching Tools Aimed At Supporting Prescriptive Sketches (Company, Contero, Naya, Aleixos)

Summary:

This paper describes tools designed for dealing with prescriptive sketches, which are sketches used to give instructions to a draftsman in charge of creating a final drawing using CAD (different from thinking sketches that go with brainstorming and talking sketches that help when discussing design with a group). The authors argue that draftsmen often simply tidy up a prescriptive sketch, which already contains all relevant information, and that a sufficiently usable computer system with good recognition could do the same thing. They did a pilot user study to compare paper-and-pencil against 2D CAD, as well as using MS Paint and a tablet to draw. Eight teachers and 22 students in engineering design and CAD participated. They were to reproduce four sample sketches in each of the mediums, and then they filled out a questionnaire to give an idea of usability. Respondents felt that tablet was more complex than hand, but none were familiar with tablet PCs, and hand drawings produced had similar quality to tablet drawings. Some disliked tablet drawings because of poor calibration of the pen. Some commented that drawing straight lines was easier with the mouse and curves were easier with the pen.

Discussion:

This paper gives a good starting point for more thorough studies on CAD, prescriptive sketching, and usability of a tablet for sketching in general -- the results are not strong enough on their own to convince people that sketch recognition for their purpose is definitely the way to go, but it might convince people that it's worth considering and worth doing more studies about, and by presenting this study and being forthright about things they could have done better, they provide a useful reference for anyone looking to study the matter further.

I think the mouse for straight lines and pen for curves preference is interesting. Is there a good way to make use of people being familiar with drawing straight lines with a mouse when creating pen-based applications? Will people want their lines to be automatically straightened all the time? (probably not, when they are trying to create free, natural sketches.) Would people like or hate being able to quickly sketch a rough drawing, then select a new tool in the interface to trace over lines that they want to be straightened? I'm not sure this is a big improvement on automatic recognition, or maybe graying out the existing drawing and letting the user re-draw a sketch with immediate recognition of components over their free, rough, "thinking" drawings.