The digital world is essentially flat. Computers, TVs, movie screens, even cellphones, display images in two dimensions.
But several latter-day Columbuses are trying to chart a digital world in three dimensions. And they've made enough progress that 3-D imaging - once a laughable Hollywood experiment - is reaching new levels of realism.
Not only is 3-D making a comeback in theaters, it's seen as a legitimate tool to enhance the work of scientists, engineers, and advertisers.
Some of the first applications of 21st-century 3-D may be in security and military areas, where a 3-D image of a bag in a security scanner, a cargo container on a dock, or a ground target from a plane may help reveal what is otherwise hidden.
Best of all: Viewers won't have to wear those goofy red- and blue-tinted glasses, experts suggest.
People see the real world in 3-D largelybecause our eyes are separated just enough to view objects from slightly different angles. That gives our vision depth of field, also called stereoscopic or binocular vision.
In 1953, Hollywood tried to recreate the effect onscreen in "House of Wax," using multiple cameras whose images were juxtaposed. The horror film turned Vincent Price into a star, but the technique never quite crossed into the mainstream. Lately, thanks to improved technology, 3-D film is making a comeback.
Last Christmas, "Polar Express" became the first Hollywood movie to be released in 3-D on IMAX, the jumbo movie screens that have popped up around the United States and the world. It was the latest of nearly three dozen 3-D films to be shown in IMAX theaters since 1985. In March, Hollywood mega-directors George Lucas ("Star Wars") and James Cameron ("Titanic") endorsed 3-D feature films as the wave of the future.
Instead of expensive and complex filming using multiple cameras, new techniques now allow movies already shot with a single camera to be converted into 3-D, opening up a whole new library of existing material. After viewing a 3-D version of a clip from his original "Star Wars" movie, Mr. Lucas declared, "it looks better than the original."
These theatrical applications - as well as the familiar 3-D attractions at theme parks - still require an updated version of the old 3-D glasses. But a number of companies, from giant Toshiba Corp. in Japan to small start-ups around the world, are looking past that technique to create "naked eye" or "autostereoscopic" 3-D images.