In virtual environment systems, the ultimate goal is delivery of the highest-fidelity user experience possible. The paper describes a general form framework for optimizing fidelity on a per-task basis. The virtual world database is priority ordered; the ordering is dynamically recomputed based on display platform, virtual world state, and (possibly shifting) task objectives. Optimization is performed with the QUICK model, which integrates ratings of representational quality, scene node importance, and machine resource cost. The approach has been implemented in a prototype display and distributed cache management system, which can be incorporated into most existing networked virtual reality applications.

We describe the Scene‐Graph‐As‐Bus technique (SGAB), the first step in a staircase of solutions for sharing software components for virtual environments. The goals of SGAB are to allow, with minimal effort, independently‐designed applications to share component functionality; and for multiple users to share applications designed for single users.This paper reports on the SGAB design for transparently conjoining different applications by unifying the state information contained in their scene graphs. SGAB monitors and maps changes in the local scene graph of one application to a neutral scene graph representation (NSG), distributes the NSG changes over the network to remote peer applications, and then maps the NSG changes to the local scene graph of the remote application. The fundamental contribution of SGAB is that both the local and remote applications can be completely unaware of each other; that is, both applications can interoperate without code or binary modification despite each having no knowledge of networking or interoperability.

Generation of a three-dimensional model from an unorganized set of points is an active area of research in computer graphics. Alpha shapes can be employed to construct a surface which most closely reflects the object described by the points. However, no /spl alpha/-shape, for any value of /spl alpha/, can properly detail discontinuous regions of a model. We introduce herein two methods of improving the results of reconstruction using /spl alpha/-shapes: density-scaling, which modulates the value of a depending on the density of points in a region; and anisotropic shaping, which modulates the form of the /spl alpha/-ball based on point normals. We give experimental results that show the successes and limitations of our method.