Hand-Based Disocclusion for the World-in-Miniature Metaphor

The world-in-miniature metaphor (WIM) allows users to select, manipulate, and navigate efficiently in virtual environments. In addition to the first-person perspective offered by typical virtual reality (VR) applications, the WIM offers a second dynamic viewpoint through a hand-held miniature copy of the environment. In this paper we explore different strategies to allow the user to interact with the miniature replica at multiple levels of scale. Unlike competing approaches, we support complex indoor environments by explicitly handling occlusion. We discuss algorithms for selecting the part of the scene to be included in the replica, and for providing a clear view of the region of interest. Key elements of our approach include an algorithm to recompute the active region from a subdivision of the scene into cells, and a view-dependent algorithm to cull occluding geometry. Our cutaway algorithm is based on a small set of slicing planes roughly oriented along the main occluding surfaces, along with depthbased revealing for nonplanar geometry. We present the results of a user study showing that our technique clearly outperforms competing approaches on spatial tasks performed in densely occluded scenes.