AN INTELLIGENT SKETCHPAD : A Gestural Language for Denoting Temporal Relations in Dynamic Design

Sketching offers an intuitive and rapid form of data compression, one in which visual ideas can be quickly expressed. Electronic sketching now allows us to capture subtleties of human hand motion articulated during the act of sketching: changes in speed, pressure, and tilt of the stylus are reflected by the input device. Computer systems should be capable of understanding the syntactic, semantic, and temporal implications of sketched input derived from the gestures used to create these sketches. The electronic medium allows for sketching on a "page" which is no longer two-dimensional but multi-dimensional and has the added dimension of time. This thesis postulates a new convention which allows us to interpret sketched marks made upon this page and to tell objects on it how to behave over time, spatially, in relation to each other and to their larger context. Their implications are then manifest in the visual appearance of the objects on this page and in changes to the behaviors of these objects over time. This thesis presents a research system referred to as an Intelligent Sketching Substrate, an electronic page which interprets sketch marks made upon it in terms of the way in which the marks are drawn. The system defines a gestural sketching language enabling a designer to express the visual appearance, spatial location, and temporal behavior of an object in a dynamic electronic environment by interpreting characteristics of sketch marks. Such characteristics include articulative, geometric, spatial, and temporal qualities expressed during the creation of these sketch marks. The prototype system is demonstrated for dynamic graphic design and animation. A designer can rapidly sketch a layout for an interactive page, using pressure and tilt to indicate the visual weight and translucency of text and images on the page and how these objects should change their appearance and behavior over time. Through the articulation of sketch marks designated to indicate motion (walking, running, etc), an animator can also use this system to produce an easily-modifiable animated scene of a 2D two-legged figure. Applications for this type of work include interactive document layout, user interface rapid-prototyping, and sketch-based storyboarding for animation. Thesis supervisor: Muriel R. Cooper, Professor of Visual Studies This work was supported by Paws, Inc., and Hewlett Packard. AN INTELLIGENT SKETCHPAD: A Gestural Language for Denoting Temporal Behaviors in Dynamic Design by Karen Donoghue The following people have served as readers for this thesis. William Buxton Professor of Computer Science Faculty of Computer Science University of Toronto, Toronto, Canada Patrick Purcell Professor of Human-Computer Interaction Faculty of Informatics University of Ulster, Londonderry, Northern Ireland