Usability of Multi-Scale Interfaces for 3D Workbench Displays

We consider that multi-scale visualization interfaces support users to view different levels of scales simultaneously and to understand large-scale, complex 3D information in 3D display environments. This article presents a user evaluation on three multi-scale interfaces on a 3D workbench display: focus + context (f + c), fixed f + c, and overview + detail (o + d). The interfaces differ in terms of (1) window arrangement and (2) positioning of detailed information relative to the user. Our goal is to identify the effect of these interface differences in large scale information visualization on a 3D workbench. To address the usability of the interfaces for a wide range of applications, we designed two tasks that differ by the level of information integration and cognitive demand. The evaluation results suggest that focus-based interfaces (i.e., the f + c and fixed f + c interfaces) are useful for tasks that require tight coupling between information layers and the o + d interface is useful for tasks performed in a densely populated information space. In terms of interface design on a 3D workbench, it is important to provide an up-close view of the current region of interest for fast scene navigation and an easy way to change viewing direction to see the 3D information from more comfortable directions. The detailed design guidelines based on the evaluation analysis are presented in this article.