Microsoft’s Kinect, a 3-D camera and software for gaming, has made a big impact since its launch in 2010. Eight million devices were sold in the product’s first two months on the market as people clamored to play video games with their entire bodies in lieu of handheld controllers. But while Kinect is great for full-body gaming, it isn’t useful as an interface for personal computing, in part because its algorithms can’t quickly and accurately detect hand and finger movements.

Now a San Francisco-based startup called 3Gear has developed a gesture interface that can track fast-moving fingers. Today the company will release an early version of its software to programmers. The setup requires two 3-D cameras positioned above the user to the right and left.

The hope is that developers will create useful applications that will expand the reach of 3Gear’s hand-tracking algorithms. Eventually, says Robert Wang, who cofounded the company, 3Gear’s technology could be used by engineers to craft 3-D objects, by gamers who want precision play, by surgeons who need to manipulate 3-D data during operations, and by anyone who wants a computer to do her bidding with a wave of the finger.

One problem with gestural interfaces—as well as touch-screen desktop displays—is that they can be uncomfortable to use. They sometimes  lead to an ache dubbed “gorilla arm.” As a result, Wang says, 3Gear focused on making its gesture interface practical and comfortable.

“If I want to work at my desk and use gestures, I can’t do that all day,” he says. “It’s not precise, and it’s not ergonomic.”

The key, Wang says, is to use two 3-D cameras above the hands. They are currently rigged on a metal frame, but eventually could be clipped onto a monitor. A view from above means that hands can rest on a desk or stay on a keyboard. (While the 3Gear software development kit is free during its public beta, which lasts until November 30, developers must purchase their own hardware, including cameras and frame.)

“Other projects have replaced touch screens with sensors that sit on the desk and point up toward the screen, still requiring the user to reach forward, away from the keyboard,” says Daniel Wigdor, professor of computer science at the University of Toronto and author of Brave NUI World, a book about touch and gesture interfaces. “This solution tries to address that.”

3Gear isn’t alone in its desire to tackle the finer points of gesture tracking. Earlier this year, Microsoft released an update that enabled people who develop Kinect for Windows software to track head position, eyebrow location, and the shape of a mouth. Additionally, Israeli startup Omek, Belgian startup SoftKinetic, and a startup from San Francisco called Leap Motion—which claims its small, single-camera system will track movements to a hundredth of a millimeter—are all jockeying for a position in the fledgling gesture-interface market.

“Hand tracking is a hard, long-standing problem,” says Patrick Baudisch, professor of computer science at the Hasso-Plattner Institute in Potsdam, Germany. He notes that there’s a history of using cumbersome gloves or color markers on fingers to achieve this kind of tracking. An interface without these extras is “highly desirable,” Baudisch says.

3Gear’s system uses two depth cameras (the same type used with Kinect) that capture 30 frames per second. The position of a user’s hands and fingers are matched to a database of 30,000 potential hand and finger configurations. The process of identifying and matching to the database—a well-known approach in the gesture-recognition field—occurs within 33 milliseconds, Wang says, so it feels like the computer can see and respond to even a millimeter finger movement almost instantly.

Even with the increasing interest in gesture recognition for hands and fingers, it may take time for non-gamers and non-engineers to widely adopt the technology.

“In the desktop space and productivity scenario, it’s a much more challenging sell,” notes Johnny Lee, who previously worked at Microsoft on the Kinect team and now works at Google. “You have to compete with the mouse, keyboard, and touch screen in front of you.” Still, Lee says, he is excited to see the sort of applications that will emerge as depth cameras drop in price, algorithms for 3-D sensing continue to improve, and more developers see gestures as a useful way to interact with machines.