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Virtual Worlds, Real Technology

Take flying, for instance. Being airborne is kind of cool-even if you’re only doing it on your computer. I discovered my powers of flight by accident. I was hanging out in Second Life, the virtual world from Linden Lab, pointing and clicking around until, suddenly, my character on screen was lifting into the sky. Houses, trees, and hills passed beneath me. When I landed, the first thing I talked about was my lame flying skills. The virtual world feeds upon itself, providing shared experiences that its inhabitants can chat about. That’s the essence of what’s being retailed here, and There. While text chat gives people a way to discuss what’s going on in the physical world, virtual worlds give you things to talk about, too-assuming you have the patience for, and interest in, participating in this consensual cartoon.

In this sense, the technology behind the virtual worlds is something like the engineering behind a theme park. To succeed, it must work well enough to create a reasonable suspension of disbelief. The virtual world needs to be complex but seamless. You need to be able to fly over a hill without crashing to a halt while the next slice of landscape loads into the computer’s memory. In the past, virtual worlds were simply not visceral enough to elicit even a hiccup of belief. Floating around a room as a disembodied smiley face, as players did in Palace, was, at best, cute; the technology could not deliver anything even remotely as compelling as a SuperFriends rerun. Though technology is catching up, Harvey says, “It’s a very difficult technical problem to provide immediate responsiveness and a fast-action feel to people who are playing with others over the Internet.”

There and Second Life solve this problem in different ways. Second Life subscribers first download a small (only about 18 megabytes) piece of software called a “thin client.” The other 320 gigabytes of data needed to simulate the virtual world-such as richly rendered 3-D graphics and high-fidelity sounds-sit on a grid of servers at Linden Lab’s San Francisco facility. Rosedale, who ran the engineering department for RealNetworks, the Seattle-based Internet media company, developed a 3-D streaming technology that delivers all the objects in the virtual world over the Internet in real time. When a subscriber logs off, the virtual world keeps on going and evolving. Log back on and things have changed in your absence.

But continuity is only one requirement for a convincing online environment. For added gravity, There employs a technology called a physics engine that enables objects and avatars to interact as in the real world. Cars collide. Paintball pellets lob through the air. Physics exists. The problem is that you have all these people in the real world, connecting to the Internet through different machines, at different speeds. How do you keep everything moving around convincingly?

The answer, for There, is essentially to stagger the simulation. Rather than conjuring up the world as a single moment in time, the servers keep track of all objects as a series of time points. When I walk next to Lexxa, for example, I see her as walking slightly ahead of me, while she sees me as walking slightly ahead of her. By rendering our experiences individually, the software convinces us that we’re in sync, just as if we were taking a stroll in real life.

But more problems persist-the foremost being that these worlds are very big. If Second Life existed in real life, it would cover roughly eight square kilometers. Rather than handling this as one large chunk of data, Second World’s software divides it into dozens of 6.5-hectare “tiles.” Each tile is maintained by a single Pentium 4 computer, running Linux, at Linden Lab’s offices. The computer handles everything from the weather patterns to the scripts that make doorbells ring. As I fly from one tile to the next, information about my surroundings is provided by another server-but for me, the transition is seamless. And as the number of users grows, the world itself expands to accommodate them.”We put new machines online as new users join the system,” Rosedale says. “It scales.”

Like those at Linden Lab, There’s servers partition its world into chunks, or sections, that are streamed to the user’s computer. But the partitioning is based on population density rather than geographical area. “If no one is in the Atlantic Ocean,” Harvey says, “then the servers can make the entire Atlantic one section. But if the more popular areas have thousands of people in them, then they have to partition in smaller pieces.”

Linden Lab and There also provide technology aimed at fostering the kind of community that sprouts naturally around chat rooms. There utilizes so-called avatar-centric communication. When I wander toward some thermal springs and encounter a group of people, my avatar is automatically positioned to face them and theirs to face me, our heads angled inquisitively, our eyes ready to lock. Once you’re engaged, you can select from a palette of preprogrammed gestures. I can choose to yawn when bored or wag my tongue if I feel like flirting in a Neanderthal sort of way. Though the expressions are canned, they evoke more intuitive responses than the trite “emoticons” of text-based chat. You don’t type a semicolon; you wink.

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