CAD systems have yet to become usable at the early stages of product ideation, where precise shape definitions and sometimes even design intentions are not fully developed. To overcome these limitations, new approaches, which we call Calligraphic Interfaces, use sketching as the main organizing paradigm. Such applications rely on continuous input modalities rather than discrete interactions characteristic of WIMP interfaces. However, replacing direct manipulation by sketching alone poses very interesting challenges. While the temptation to follow the paper-and-pencil metaphor is great, free-hand sketch recognition remains an elusive goal. Further, using gestures to enter commands and sketches to draw shapes requires users to learn a command set – sketches do not enjoy the self-disclosing characteristics of menus. Moreover, the imprecise nature of interactions presents additional problems that are difficult to address using present-day techniques. In this paper we approach the three p...
João Paulo Pereira, Joaquim A. Jorge, Vasco