A Bridge between Virtual Worlds

Second Life's new program links virtual environments.

The first steps to developing virtual-world interoperability are now being tested between Second Life and other independent virtual worlds, thanks to the launch of Linden Lab's Open Grid Beta, a program designed for developers to test new functionality. The beta program will allow users to move between a Second Life test grid--a set of servers simulating a virtual world--and other non-Linden Lab grids running the OpenSim software. OpenSim is an independent open-source project to create a virtual-world server.

Linking worlds: Two avatars, Brian White (left) and Butch Arnold, meet in 3rd Rock Grid, an independent OpenSim-based server. Credit: Brian White

The discussion of linking together today's virtual worlds is not new, but this is the first running code that demonstrates previously hypothetical approaches--another tangible sign that Linden Lab is serious about interoperability. "We are still early in the game. The point of the beta is to give the rest of the development community the chance to try the protocols themselves," says Joe Miller, Linden Lab's vice president of platform and development. More than 200 users have signed up for the beta program, and currently 15 worlds have been connected.

In order to test virtual-world interoperability, a person needs at least two virtual worlds. For Linden Lab, the OpenSim project was a natural choice. It began in January 2007 at the nexus of two open-source projects--one to reverse-engineer the Second Life server APIs, and the other Linden Lab's open-source viewer initiative. The goal of the OpenSim project is to build a virtual-world server that supports the Linden Lab viewer or a derivative.

Today, there is a flourishing OpenSim community with 26 registered grids hosting approximately 2,300 regions. While this is certainly a small number compared with the 28,070 regions that make up the Second Life main grid, it still represents a significant number of independent virtual worlds. The open-source nature of the project, combined with the number of participants and the shared support of a common viewer, make OpenSim-based worlds ideal for interoperability tests.

Interoperability is the future of the Web, says Terry Ford, the owner and operator of an OpenSim-based world called 3rd Rock Grid. Ford is also participating in the program. "It may be [in] OpenSim's future, or maybe another package will spring up, but just as links from a Web page take you to another site, people will come to expect the ability to navigate between virtual worlds," he says.

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Ford is Butch Arnold in Second Life, Butch Arnold in 3rd Rock Grid, and Butch Arnold in the OpenLife grid, and that's kind of the point. No one wants to have as many avatars as they do website accounts, but there is a fundamental difference between accounts, which hold data like a shopping cart, and avatars, which contain data regarding a person's virtual-world appearance. IBM's David Levine, who has been closely collaborating with Linden Lab on the interoperability protocols, says, "You don't care if your shopping-cart contents in your Amazon account [are] the same as other shopping carts. However, if you were moving region to region and had very different assets in each, that would be a problem."

Yet many efforts to let users share their avatars on the Web have not been successful. Levine says that the Open Grid Protocol has a chance because it is less ambitious. "We are not trying to do it across the entire Web. The focus is on the Linden main grid and a set of broadly similar grids."