Extending the tabletop display to the third dimension using a stereoscopic projection offers the possibility to improve applications by using the volume above the table surface. The combination of multi-touch input and stereoscopic projection usually requires an indirect technique to interact with objects above the tabletop, as touches can only be detected on the surface. Triangle Cursor is a 3D interaction technique that allows specification of a 3D position and yaw rotation above the interactive tabletop. It was designed to avoid occlusions that disturb the stereoscopic perception. While Triangle Cursor uses an indirect approach, the position, the height above the surface and the yaw rotation can be controlled simultaneously, resulting in a 4 DOF manipulation technique. We have evaluated Triangle Cursor in an initial user study and compared it to a related existing technique in a formal user study. Our experiments show that users were able to perform all tasks significantly faster with our technique without loosing any precision. Most of the subjects considered the technique easy to use and satisfying.

@InProceedings{SVH11,
  author       = "Strothoff, Sven and Valkov, Dimitar and Hinrichs, Klaus H.",
  title        = "Triangle Cursor: Interactions With Objects Above the Tabletop",
  booktitle    = "Proceedings of the ACM International Conference on Interactive Tabletops and Surfaces",
  pages        = "111--119",
  year         = "2011",
  publisher    = "ACM",
  keywords     = "3D interaction, multi-touch interaction, selection technique, stereoscopic display, tabletop display",
  url          = "http://viscg.uni-muenster.de/publications/2011/SVH11"
}