There is a reason why the humble mouse has been the default controller of computers for nearly 30 years: it just works.

Whether it's scrolling up and down webpages or adding fine details to an image in Photoshop, the mouse has proven to be an easy-to-master tool that does it all.

Its dominance, however, is fading. With touch-screen tablets expected to outsell desktops and laptops by next year — a feat smartphones have already accomplished — most computers will soon be controlled by means other than a mouse, if that isn't the case already.

In the grand scheme of computing, the traditional point-and-click device will ultimately be relegated to niche uses, such as ones where fine-grained control is needed.

Into this milieu steps Leap Motion, the San Francisco-based start-up that has created a compelling gesture device that lets users control their computers with their hands and fingers.

Co-founder David Holt came up with the technology after deciding the mouse's accuracy wasn't actually all that fine-grained. He was frustrated that it took so long to create three-dimensional models on his computer when it only took a few seconds to do so with a lump of clay in the real world.

3D touch control

In that vein, the Leap Motion controller is an effort to bring simple, 3D touch-control to computing.

It's similar to Microsoft's Kinect attachment for the Xbox 360 game console, but more accurate and on a smaller scale, intended for use with desktops and laptops.

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Leap Motion's Michael Buckwald: Be patient, the apps are coming. (Leap Motion website)

Touting an accuracy down to 1/100th of a millimetre, it has — not surprisingly — been the subject of much hype and anticipation since its unveiling last year.

The controller is set to ship, finally, on July 22. Does it live up to the hype? Does the mouse have anything to fear?

Not at this point. Having spent the weekend with Leap's device, it's clear that it's brimming with potential, but it may be a while before application developers figure out how to really tap into it.

The device is amazingly small, about the size of a cigarette lighter, and plugs into a computer, Mac or Windows, via a USB plug.

Set-up and account creation is simple, while a quick orientation explains what the controller does. Its cameras detect hand and finger movements in a relatively large, two-foot hemisphere above and around it, in full three dimensions.

From there, it's off to Leap Motion's Airspace app store, which will be familiar to any smartphone user.

At launch, Airspace is housing about 75 apps for both Mac and Windows — some exclusively for one platform or the other — at prices ranging from free to a few dollars.

The first app I fired up was Boom Ball, a pinball-like game reminiscent of the arcade classic Arkanoid, where you bounce a ball with a paddle at a bunch of coloured blocks. The paddle in this 3D game is, however, your finger, which you can angle in order to aim the ball as it bounces.

The accuracy is impressive, especially when it came to angles. Even though it works on a smaller scale, it's clear the Leap controller is more accurate than the Kinect.

Unfortunately, Boom Ball was about as good an experience as I had.

Mostly mouse

Next up, I tried Touchless, an app that lets you control your computer's desktop with gestures. It works, but it can be painful.

To close a Mac window, for example, you have to carefully aim your finger over the small red dot in its corner, then slowly poke forward.

It does the job amazingly, but it's about a thousand times faster and easier to do this with a mouse or trackpad. It should take only a millisecond to open and close windows and programs, not a second or two. Who has that kind of time?

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Google brought out its own Chromebook touch-screen device in February. Because of smartphone swiping, consumers are getting used to that technique. (Associated Press)

Conversely, I tried Cut the Rope, a smartphone and tablet game that has been reformatted for Leap's gesture control.

As the title implies, the idea is to cut the ropes attached to a ball so that you can swing it into other objects. Here, the accuracy was a little off, which got me thinking about how easily the game can be played on a touchscreen, where fast swipes seem to work more effectively.

Clearly, as these two examples illustrate, there are situations where the Leap controller won't be the preferred method of input.

So what about the fine-grained 3D control apps, the sort of thing that inspired Holt to create the technology in the first place?

These look to be few and far between so far. A plug-in for Autodesk's high-end modelling program Maya exists, but not being a high-end designer with the program already installed, I wasn't able to test it.

Corel's Painter Freestyle, essentially a painting app for Windows, may offer the best glimpse of the Leap controller's potential. Holding a pencil as a "brush," I got a kick out of virtually painting on my computer screen.

The interface and accuracy are a bit wonky, but with a little refinement, I can see such painting apps taking off.

At launch, the Airspace app store is coming out with plenty of experimental musical and visualizer apps, ranging from virtual piano and drum simulators in Chordion Conductor and AirBeats, respectively, to the trippy Lotus and Gravilux, which play music and display fluctuating graphics in time with hand movements.

They're quirky and fun, for a while anyway. But I couldn’t find a single killer app among the launch offerings.

I had high hopes for Google Earth, which has been updated to work with the Leap controller, but it obviously still needs work. Its gesture control was way too sensitive, resulting in the world spinning away as soon as you launch it.

I asked Leap Motion co-founder Michael Buckwald about the lack of strong showcase apps and he said they're on the way.

He says the quality of apps has already improved significantly in the short time the Leap controller has been in developers' hands, but that gesture control for computers is an entirely new platform and it will take time for app developers to figure out the full possibilities of the technology.

I wondered if Leap could end up like Nintendo's Wii game console and Microsoft's Kinect. Both were heavily hyped smash hits out of their respective gates, but ultimately proved to be novelties that both developers and consumers abandoned.

The difference with Leap, Buckwald says, is that it has stronger technology that is going to keep improving.

The $79 device itself is comprised of inexpensive, off-the-shelf hardware, with almost all of its "magic" coming from the company's software.

Wii and Kinect "petered out because the underlying technology wasn't able to deliver what people expected the content to [be]

. Developers were just running into the ceilings created by that technology," Buckwald says.

"In our case, it's quite different because right now the content is only using a tiny percentage of the capabilities of the underlying technology."

I also wondered where gesture control of computers might ultimately fit – is there room for it in between the mouse and touch screens?

In using certain apps, both my wife and I found ourselves – funnily enough – pushing our fingers toward the computer screen and in some cases touching it, obviously the result of subconscious touch-screen conditioning.

Buckwald says Leap has two advantages over touch screens. Two-dimensional experiences such as Cut the Rope, for example, don't scale up to larger displays very well if they are touch-controlled. Such games and apps may work well on a smartphone or tablet, but beyond that they require a different form of input, namely gesture.

Otherwise, when it comes to 3D-based applications such as modelling, there's no contest between the methods of input, he says.

"You can’t reach in and pull something toward you with a touchscreen."

It strikes me that the ultimate issue with gesture control may not be on the input side, because that is clearly becoming more accurate very quickly, but with the output.

While it's great that devices such as Leap allow for three-dimensional control, their effectiveness at this point seems limited by what users are seeing.

In other words, is 3D control useful or desirable when we have to implement it on 2D screens?

Until output displays are in full three dimensions — a future that may or may not ever arrive — it's not clear that there's a need for three-dimensional inputs such as the Leap controller.