The tangible 3D tabletop combines tangible tabletop interaction with 3D projection in such a way that the tangible objects may be augmented with visual data corresponding to their physical shape, position, and their orientation on the tabletop. In practice, this means that not only the tabletop, but also the tangibles themselves may serve as displays. We present the fundamental ideas for this interface, particularly those concerning the interplay between 2D and 3D representations on the tabletop and the tangibles, and present examples of how it might be used in the domain of maps and geolocalized data. This concept also leads to discussions of design considerations concerning the combination and connection of content and functions of tangibles and tabletop surfaces, the use of tangibles as dynamic displays and input devices, and the visual effects made possible by the combination of 2D and 3D representations on tabletop surface and tangibles.
Tangible Urban Planning is an early exploration of how 3D tabletops can support collaborative activities in urban planning and development projects. On the tabletop surface we project a road map representing the neighborhood of concern for the urban planning process. Moreover we operate with two kinds of tangibles: cuboid (boxes) representing buildings and cylinders, which acts as controls or interaction objects. The cuboids are white object, but when put on the table surface colour and façade elements are projected onto the object. As part of Tangible Urban Planning installation we have in addition to tangible tabletop itself a display used for visualizing a camera view into the three-dimensional world represented by tangible 3D tabletop itself. The camera view is controled by a white cylindrical shape interaction object with a small arrow on top of it, which represent the direction of view. Buildings can be put on the table surface and moved around while the camera view simultaneously is updated on the separate display. An additional interaction element may be used for changing the colour of the facade of a building by positioning the interaction element close to a building and turning the cylinder to select a colour. By moving the camera interaction object on the table surface, i.e. the road map, the corresponding first person camera view is shown on the separate display. A third interaction object may be used for controlling the position of the sun or the time of the day by turning a dial.
