Virtual worlds come in two forms. Some, like Second Life, are 3-D, requiring users to install programs that run most smoothly on computers equipped with high-end graphics capabilities. Others, like Disney's Club Penguin, are browser-based environments that can be accessed through older computers--even those that access the Internet using dial-up modems. Each form has its drawbacks: not everyone has the computing power to get into a 3-D virtual world, but the browser-based worlds don't have the breathtaking, immersive qualities of 3-D. Today, at the Virtual Worlds conference in New York City, Multiverse, a company based in Mountain View, CA, that provides foundations for virtual worlds, will show new technology that allows developers to build virtual worlds that users can access in either a rich, 3-D form or a simpler, browser-based form.

"For worlds that take advantage of this, you as a player may not actually know if the people you're talking to are accessing a 3-D world or coming in via 2-D," says Corey Bridges, cofounder and executive producer of Multiverse. This is important, he says, because it gives virtual worlds the flexibility they need to reach a larger audience. Developers can build virtual worlds with beautiful 3-D graphics without shutting out users with older computers. The flexibility also allows the possibility that the user might experience a virtual world in different ways throughout the day, perhaps accessing the 3-D version from a home computer, and then later accessing the browser-based version from a mobile device. "We knew that virtual worlds were more than just PC-based experiences," Bridges says.

The demonstration will take place in a virtual Times Square. Bridges says that the company will showcase the photo-realistic 3-D version of the environment, spotlighting two users interacting there through 3-D virtual representations of themselves, called avatars. Then, Multiverse will show the other side of the conversation: a cartoonish Flash animation running through a browser.

The switch is made possible, Bridges says, by the way Multiverse has designed its system. Most virtual worlds are hosted by servers customized for close interaction with specially designed clients at the user's end. In contrast, Bridges says, "we built our servers to not know how the world in question is being displayed." Multiverse servers perform typical server functions, such as resolving conflicts, determining the results of character interactions, communicating those results to clients, and collecting responses. However, they're not as closely tied to specific clients, Bridges says, adding that a Multiverse server could run an old-style text-based game or a 3-D virtual world and hardly know the difference. The client is entirely responsible for how the world is displayed. Developers building worlds through Multiverse can decide which kinds of experiences their worlds will support and build the corresponding clients. Worlds could be built to work only in Flash or only in 3-D, just as they could be built to work with both.