We are developing a framework for creating interactive 3D environments for applications in design, education, and the communication of information and ideas [3]. Our most recent work focuses on providing a useful and powerful interface to such a complex environment. To this end we have developed 3D widgets, objects that encapsulate 3D geometry and behavior, to control other objects in the scene [2]. We build 3D widgets as first-class objects in our real-time animation system. Becauseour system allows tapid prototyping of objects, we hope to enlarge today’s surprisingly small vocabulary of 3D widgets that includes menus floating in 3D, gestural picking, translation and rotation, cone trees, and perspective walls.

As a way to focus on issues of 3D widget design, we have developed widgets to perform aparticular task: applying high-level deformations to 3D objects [1]. The complexity of these operations makes numerical specification or panels of sliders difficult to use, and yet direct manipulation interfaces cannot provide meaningful feedback without fixing most parameters. In this video paper, we show a set of new 3D widgets to control deformations called racks. A simple rack consists of a bar specifying the axis of deformation and some number of handles attached to the bar speci~ ing additional deformation parameters. For example, a taper rack has two additional handles. Moving the ends of the handles towards or away from the axis bar changes the amount of taper of the deformed object; changing the distance between the handles changes the region over which the deformation is applied. A mom complex rack can have multiple handles specifying different deformations. The racks in Figures 1–3 all have handles for twisting (purple), tapering (blue), and bending (red) an object. The deformation range is the region between the twist and taper handles.