travel

=Travel=

toc This article defines a word and clarifies its application and usefulness in scale studies. It is only the word's use in formal langauges of imaging and mathematics that applies to scale studies.

=Overview= Travel is the most common interaction technique for large-scale 3D environments, and, as such, has been the subject of considerable study. It represents motor activity controlling the position and orientation of the viewpoint. A major challenge of 3D travel is the mapping of control values from the input device (often only 2 degrees of freedom) to the parameters of a virtual camera model (7 or more, including 3 for position, 3 for orientation, and 1 for field of view). To address this challenge, a number of travel interface metaphors have been developed, including: “walking” and “flying” viewers, target-selection methods, and “world-inhand” metaphors. Bowman et al. have proposed a taxonomy for classifying the components of travel techniques along with methods for evaluating their effectiveness for specific tasks. The issue of speed control is particularly important for environments that are very large or sparse, and for environments with objects that exist at diverse spatial scales. Mackinlay et al. were among the first to describe a general and effective method for rapid, controlled movement in such 3D environments. Celestia supports an exponential zoom feature to visit nearby galaxies using extended precision arithmetic. Mine et al. investigated the problem of manipulating objects in 3D virtual environments, and proposed the automatic scaling technique to select, grab, manipulate, and release virtual objects.

See also orienteering, translation