Freeform user interfaces for graphical computing

It is difficult to communicate graphical ideas or images to computers using current WIMP-style GUI. Freeform User Interfaces is an interface design framework that leverages the power of freeform strokes to achieve fluent interaction between users and computers in performing graphical tasks. Users express their graphical ideas as freeform strokes using pen-based systems, and the computer takes appropriate actions based on the perceptual features of the strokes. The results are displayed in an informal manner to facilitate exploratory thinking. This paper explores the concept of Freeform UI and shows its possibilities with four example systems: beautification and prediction for 2D geometric drawing, a stroke-based 3D navigation, an electronic office whiteboard, and a sketch-based 3D freeform modeling. While Freeform UI is not suitable for precise, production-oriented applications because of its ambiguity and imprecision, it does provide a natural, highly interactive computing environment for pre-productive, exploratory activities in various graphical applications.