Using solid diagrams for tangible interface prototyping

In most design disciplines, early concept development involves paper-and-pencil brainstorming. However, we've found that when designing a tangible user interface, it's best to start with a solid diagram - a 3D "sketch" created using simple construction materials. In the early stages of research and concept development, solid diagrams are more suitable for rapid reconfiguration and exploration than pencil sketches. They also let us analyze modes of correspondence between physical structures and abstract-information structures. Furthermore, because we can manipulate these diagrams, they help us explore usability properties and certain design trade-offs.