Informal, sketch-based design tools closely match the work practices of user interface designers. Current tools, however, are limited in the size and complexity of interaction that can be specified. We have created an advanced sketch-based visual language that allows for easy prototyping of large, complex interactive designs. In its current embodiment in the DENIM web design tool, the visual language allows designers to sketch reusable components for recurring page elements, such as navigation bars, as well as conditionals to illustrate and test transitions that depend on a user's input. Designers can also specify sites that accept richer user input than simple clicking. Our informal evaluation shows that these features allow designers with little programming experience to quickly create prototypes of large, complex web sites while still working inside an informal, sketch-based environment. KEYWORDS Visual language, DENIM, user interface design, web design
James Lin, Michael Thomsen, James A. Landay