TEVE KASH is living in his own little world, but guests are welcome to drop in for a chat. Flyby's Hangar is the three-dimensional structure Mr. Kash calls home on the World Wide Web. Visitors can circle the music room, then scoot up a set of stairs and take an elevator to the roof garden, where a brook burbles loudly.
Mr. Kash's walls are bare. A Guggenheim curator, Matthew Drutt, on the other hand, has nothing but art in the Guggenheim Virtual Museum, a three-dimensional gallery that is expected to open to the Webgoing public before the year ends. Mr. Drutt declined to describe the museum's vertical surfaces as walls, though. "I think more in terms of skins," he said, "because the art is visible from the outside as well as the inside."
Space. It may not be the Internet's final frontier, but it could be its next one. From Mr. Kash's humble abode to the Guggenheim's elaborate showcase, Web browsers are displaying characters, objects and spatial environments as if they existed in three dimensions rather than on a flat screen.
Although the illusion of fuzzy dice, U.F.O.'s or other items floating in the air still takes special glasses or awkward virtual-reality headgear, 3-D programs let computer users inhabit online homes equipped with stereo systems and other amenities, explore virtual cities and take new products for a 360-degree spin.
Information architects assert that 3-D creations encourage communication, enhance education, clarify complex data and stimulate online sales, along with giving Web surfers a more lifelike environment.
On the Internet, 3-D "is going to change the world," said Neil Trevett, president of the Web3D Consortium, an industry group trying to establish the technical standards for delivering 3-D data online. "The question is when, not if."
Game players are accustomed to viewing 3-D scenes on their monitors, but until recently, the sheer amount of data needed to convey even a vaguely realistic 3-D environment on the Web made the task impractical. With the availability of faster connections, improved file-compression programs and more powerful computers that can handle graphics more easily, the situation is changing.
As a result, 3-D is popping up all over. The Sharper Image's online store lets visitors examine the Turbo-Groomer and 20 other items from all angles. And potential real- estate buyers can take virtual property tours from distant cities.
Not all of the endeavors strive for photographic-quality realism. Firms like Lava.com, Wild Tangent and Geometrek offer "music visualization" scenes: colorful 3-D landscapes that swirl and throb in time to the beat of an MP3 song file. And artists are experimenting with creating unconventional 3-D works.
Adding a spatial dimension to cyberspace is a natural development, said Hal Thwaites, a communications professor at Concordia University in Montreal who has a special interest in 3-D technologies.
"We live in a three-dimensional world," Mr. Thwaites said. "Historically, representations of that world have been flat, so people have constantly been trying to make them more like the real world. We've been chasing virtual reality for a long time, from cave paintings all the way up to computer- immersive environments.
"One of the intriguing things about virtual reality is that you can go places and do things that you could never possibly do in real life: be a fish in the middle of the ocean or a bird flying over the mountains. That's what really sparks people's imaginations about 3-D environments."
For Mr. Kash, that means an opportunity to converse with people he would otherwise not talk to.
Mr. Kash, a 49-year-old locksmith in Napa., Calif., is also the mayor of Cybertown, a virtual village. In addition to its main plaza, city hall and residences, the town's 3-D elements include the on-screen avatars for Cybertown's 450,000 residents. The avatars circulate in the digital setting while their human controllers chat with one another through typed exchanges.
At Flyby's Hangar, a gathering might be attended by a bikini-clad beachcomber, a floating cube with sides made of live Webcam images and, if Mr. Kash is present, an F-17 fighter jet. "It's exciting because you never know who's going to drop in," he said.
Mr. Drutt, the Guggenheim curator overseeing the virtual-museum project, said his institution hoped to create an online space as distinctive as the museum's landmark Frank Lloyd Wright building on Fifth Avenue in Manhattan or its Frank Gehry-designed structure in Bilbao, Spain — but without traditional architectural limitations.
"We're not dealing with bricks and mortar, so why render an architecture that's based on gravitational needs?" Mr. Drutt asked. The Guggenheim retained a New York architectural firm, Asymptote Architecture, to design the virtual museum. After the virtual ribbon-cutting ceremony, museumgoers will be able to wander the galleries, eyeing reproductions from the Guggenheim's collection as well as digital artwork made for the Internet.
Most 3-D demonstrations online still aspire to recreate reality. And they are getting better at it, although some longstanding problems remain unsolved.
Plug-ins have plagued the 3-D community for years. If you want to watch a 3-D scene, you are expected to download a hefty file through a pokey modem and then hope your computer's graphics card can handle it. But first, the correct 3-D plug-in is needed, which requires additional downloading and a sometimes-tricky installation. As hard drives have become cluttered with 3-D viewers, content developers have had to choose CosmoPlayer, WorldView, Viscape or another option and can rarely afford to remake the same material for different plug- ins.
It wasn't supposed to be that way. When Mark Pesce and several other visionary programmers approached the first meeting of the World Wide Web Consortium in 1994, they proposed a standard technique for describing 3-D scenes to a computer. Virtual Reality Modeling Language, or VRML (pronounced VUR-mel), was to be the 3-D equivalent of Hypertext Markup Language, or HTML, the standard method for displaying 2-D Web pages. Like Linux, the open-source operating system, everyone was welcome to contribute to VRML's technical specifications.
But VRML, even after an update in 1997, did not go far enough in specifying how complex data should be conveyed, and that omission spawned a plethora of plug-ins that addressed problems in different ways. Then a wave of software-industry consolidations and layoffs stalled update programs, and most 3-D content development stopped.
By 1998, most observers decreed that VRML was dead. But Sandy Ressler, the host of the most comprehensive 3-D resource online (web3d.about.com), contests that notion. "VRML was ahead of its time," said Mr. Ressler, a virtual-reality project manager for the National Institute of Standards and Technology in Gaithersburg, Md.
Members of the Web3D Consortium are currently updating VRML for the next generation of HTML, and that approach may influence how 3-D is rendered in interactive set-top boxes for digital television. But a number of companies are also pursuing their own online 3-D strategies in the hopes of establishing a new standard.
For example, Macromedia, maker of the popular Shockwave Web-animation software, recently announced that it was working with Intel to develop its own approach to online 3-D.
In all, about 40 companies have ideas about how 3-D should be displayed on the screen. As before, each requires its own plug-in. But faster connections and larger hard drives have made consumers less resistant to taking the steps necessary to view 3-D environments. Companies have also shrunk the size of both the plug-ins and the 3-D files.
A company called Mediadome has just introduced a 3-D browsing environment that thrusts users into the middle of an animated nightclub, complete with flashing lights and dancers that busily boogie in time to the music (www.mediadome.com). A video screen displays a 2-D browser window; others respond to MP3 song files as they play, directing viewers to sites related to each song's performer.
E-commerce sites also are tinkering with 3-D. While everyone knows what books and CD's look like, more complex items could benefit from online demonstrations. ATI, the graphics-card maker, provides elaborate 3-D demonstrations for its four newest cards. The firm has reported a 13 percent increase in online sales since it posted the models four months ago. Bal Sahjpaul, ATI's Internet marketing manager, said, "If a picture is worth a thousand words, than the 3-D Web is worth a billion words."
Admittedly, some 3-D offerings have fallen flat.
A 3-D search engine on the Excitextreme.com site runs slowly and assembles circular clusters of unrelated results. A Ticketmaster.com feature called View From Your Seat allowed visitors to try the view from seats in 50 sites before buying tickets, but it functioned erratically. "It was a wonderful thing when it worked," said Tom Stockham, Ticketmaster.com's president, who vowed to reinstate the feature when it became more reliable.
Even when 3-D is working properly, it takes some getting used to. There are no standard controls for navigating a 3-D space, so the uninitiated may find themselves careering around a virtual room or, if a surface's "collision detection" feature has been enabled, slamming into an impermeable digital lamppost.
While consumers and programmers try to slash a path through the thorny 3-D landscape, some engineers are already looking ahead. At the Sony United States Research Laboratories in San Jose, Calif., a team is developing a new format, called Blendo, that would place television-quality video within a navigable 3-D environment. The results could be viewed on a television, a home computer or a game console.
Rob Myers, a Sony media architect, emphasized that the programming was meant to unfurl in a linear fashion, which means that a news broadcast would move from headlines to weather to sports. But viewers could spin an on-screen globe during the weather segment to retrieve regional weather forecasts.
"We support traditional television narrative form," Mr. Myers explained. "I think you'll find that pretty different from a lot of the Web 3-D stuff, which is sort of a poke- and-go thing. Don't get me wrong. We love 3- D. We're just not trying to justify 3-D as the end itself. It's one piece of the vocabulary."
For John Klima, 3-D is an end in itself. Mr. Klima, a New York artist, recently started Glasbead.com, which he described as an interactive, collaborative musical toy. After downloading the program, viewers can upload sound files to shafts within a sphere, then spin and play the virtual instrument while others who are connected at that moment do the same.
The appeal of 3-D, Mr. Klima said, is that "there's just tons of artistic elbow room."
He continued: "If you move away from simulating reality and toward the creation of a not-yet-existing reality, the possibilities seem endless. It's only just begun — 3-D artists are sticking their hands in berry juice and slapping the cave wall."