The Open Simulator (OpenSim) project is developing an open source simulator that is compatible with the Second Life viewer, but opening up innovative applications centering on a virtual three-dimensional world.
Free • Open Source
What is Hippo OpenSim Viewer?
The Hippo OpenSim Viewer helps users take advantage of OpenSim features and extensions. Based on the source code of the Linden viewer, which is published under GPL, Hippo OpenSim Viewer is compatible not only with the Second Life grid but with all the grids running Open Simulator. The additional features allow exploiting the potential of the Open Simulator world and provide a user-friedly way to connect to the multitude of OpenSim grids. This is a client only in order to connect to a region-world you need to run a server like OpenSim or connect to an existing one like SecondLife.