We describe the development and evaluation of a large-scale multimodal virtual reality simulation suitable for the visualization of cultural heritage sites and architectural planning. The system is demonstrated with a reconstruction of an ancient Greek temple in Messene that was created as part of a EU funded cultural heritage project (CREATE). The system utilizes a CAVE-like theatre consisting of head-tracked user localization, a haptic interface with two arms, and 3D sound. The haptic interface was coupled with a realistic physics engine allowing users to experience and fully appreciate the effort involved in the construction of architectural components and their changes through the ages. Initial user-based studies were carried out, to evaluate the usability and performance of the system. A simple task of stacking blocks was used to compare errors and timing in a haptics-enabled system with a haptics-disabled system. In addition, a qualitative study of the final system took place while it was installed in a museum.

We present a scalable implementation of a network partitioning scheme that we have called frontier sets. Frontier sets build on the notion of a potentially visible set (PVS) [1][22]. In a PVS, a world is sub-divided into cells and for each cell all the other cells that can be seen are computed. In contrast, a frontier set considers pairs of cells, A and B. For eac`h pair, it lists two sets of cells, FAB and FBA. By definition, from no cell in FAB is any cell in FBA visible and vice-versa. Our initial use of frontier sets has been to enable scalability in distributed networking. In this paper we build on previous work by showing how to avoid pre-computing frontier sets. Our previous algorithm, required O(N 3) space in the number of cells, to store pre-computed frontier sets. Our new algorithm precomputes an enhanced potentially visible set that requires only O(N 2) space and then computes frontiers only as needed. Network simulations using code based on the Quake II engine show that frontiers have significant promise and may allow a new class of scalable peer-to-peer game infrastructures to emerge.