The ZCam camera from 3DV System was a motion-sensitive predecessor to today's 3-D gesture system technology.

AP Photo/Paul Sakuma

How do you redefine a user interface? What steps do you need to take to change the way people interact with technology? It's not just a matter of developing the right tools. You also have to take into account the way people want to use gadgets. The most technologically advanced interface means nothing if it just doesn't feel right when you're taking it out for a spin.

But we're entering an era in which we need to revisit user interfaces. Computers pop up in more gadgets and applications each year. Within a decade, even the most basic appliance might house a type of computer. And with a growing emphasis on 3-D video, a new way to take advantage of this third dimension requires an innovative approach.

A 3-D gesture system is one way to tackle this challenge. At its most basic level, a 3-D gesture system interprets motions within a physical space as commands. Applications for such technology fall across the spectrum of computing from video games to data management. But creating a workable 3-D gesture system presents a host of challenges.

Several engineers have tried to create systems that can interpret our movements as computer commands. But what kinds of applications will these systems make possible? And what kinds of components are necessary to put together a 3-D gesture system?