Virtual worlds attract millions of users and these popular applications are supported by gigantic data centers with myriads of processors. However, surprisingly, virtual worlds are still unable to host simultaneously more than a few hundred users in the same contiguous space.
The main contribution of the thesis is Kiwano, a distributed system enabling an unlimited number of avatars to simultaneously evolve and interact in a contiguous virtual space. In Kiwano we employ the Delaunay triangulation to provide each avatar with a constant number of neighbors independently of their density or distribution. The avatar-to-avatar interactions and related computations are then bounded, allowing the system to scale. The load is constantly balanced among Kiwano's nodes which adapt and take in charge sets of avatars according to their geographic proximity. The performances have been evaluated simulating tens of thousands of avatars connecting to a Kiwano instance running across several data centers, with results well beyond the current state-of-the-art. This indicates Kiwano to be a cost effective solution for the industry.
Kiwano has been successfully implemented for HybridEarth, a mixed reality world, Manycraft, our scalable multiplayer Minecraft map, and discussed for OneSim, a distributed Second Life architecture. By handling avatars separately, we show interoperability between these virtual worlds.