Worldlets: 3D Thumbnails for Wayfinding in Large Virtual Worlds

Finding one’s way to sites of interest on the Web can be problematic, and this difŽculty has been recently exacerbated by widespread development of 3-D Web content and virtual-world browser technology using the Virtual Reality Modeling Language (VRML). Whereas travelers can often navigate 2-D Web sites based on textual and 2-D thumbnail image representations of the sites’ content, Žnding one’s way to destinations in 3-D environments is notoriously troublesome. WayŽnding literature provides clear support for the importance of landmarks in building a cognitive map and then using that map to navigate in a 3-D environment, be it real or virtual. Textual and 2-D image landmark representations, however, lack the depth and context needed for travelers to reliably recognize 3-D landmarks. This paper describes a novel 3-D thumbnail landmark affordance called a worldlet. Containing a 3-D fragment of a virtual world, worldlets offer travelers Žrst-person, multi-viewpoint experience with faithful representations of potential destinations. To facilitate an investigation into the comparative advantages of landmark affordances for wayŽnding, worldlet capture algorithms were designed, implemented, and incorporated into two VRML-based virtual environment browsers. Findings from a psychological experiment using one of these browsers revealed that, compared to textual and image guidebook usage, worldlet guidebook usage: nearly doubled the time subjects spent studying the landmarks in the guidebook, signiŽcantly reduced the time required for subjects to reach landmarks, and reduced backtracking to almost zero. These results support the hypothesis that worldlets facilitate traveler landmark knowledge, expedite wayŽnding in large virtual environments, and enable skilled wayŽnding.