Visualizing information nets in three dimensions
At present it is not clear if it is worth presenting abstract data in 3D, although there is a small body of evidence to support the idea. This paper reviews the evidence and reports on two new experiments that provide some compelling data showing that head coupled perspective transformations combined with stereo viewing can dramatically increase the size of the information structures that can be perceived. The first experiment was designed to provide the first quantitative measurements of how much more (or less) can be understood in 3D than in 2D. The 3D display used was configured so that the image on the monitor was coupled to the user's actual eye positions (and it was updated in real-time as the user moved) as well as being in stereo. Thus the effect was like a local "virtual reality" display located in the vicinity of the computer monitor. The results from this study show that true 3D viewing can increase the size of the graph that can be understood by a factor of three; using stereo or head coupling alone produce lesser advantages. The second experiment looked at a variety of viewing methods, both 2D and 3D, with and without stereo, and with and without motion. The results show that structured 3D motion and stereo viewing both help in understanding, but that the kind of motion is not particularly important; hand guided motion, head coupling (as in virtual reality displays) and automatic rotation all improve performance. These results provide strong reasons for using advanced 3D graphics for interacting with a large variety of information structures.