Hardware and setup
The Leap hardware is actually quite unassuming, considering its capabilities. It's just over three inches long, an inch wide and less than a half-inch thick (79 x 30 x 11mm), with a glossy black panel on top, behind which resides the infrared sensors. On the bottom, you'll find a black rubber panel embossed with the Leap Motion logo. The edge, meanwhile, is ringed with a seamless aluminum band, save for a USB 3.0 Micro-B port on the left side (though the device runs at USB 2.0 speeds). There's also a slim LED power / status indicator on the front edge. Alas, as of this writing, the company wasn't able to reveal more specifics about the internals themselves, thanks to pending patent considerations. Along with the controller itself, users get a pair of USB 3.0 cables in the box -- a 5-foot and a 2-foot cord.
Keep in mind, the Leap is different from a Kinect sensor bar in more than just its size and appearance. Leap works using infrared optics and cameras instead of depth sensors, and does not cover as large an area as Microsoft's gestured controller. Leap does its motion sensing at a fidelity unmatched by any depth camera currently available: it can track all 10 of your fingers simultaneously to within a hundredth of a millimeter with a latency lower than the refresh rate on your monitor. Of course, that tracking ability isn't just about the hardware, and the capabilities of the Leap are only realized by the software built to work with it.
Setting up the Leap is a straightforward affair. Simply plug one end into the laptop, the other into the controller and position it in a location where it can see your hands; in front of a laptop or between a desktop keyboard and screen generally works. Once you're plugged in, you'll see the green LED on the front of the device and the infrared LEDs beneath the top plate come to life. From there, it's a matter of downloading the appropriate Windows or Mac Leap Motion software suite (consumers will be prompted automatically to do this upon connecting the device). That download includes both a diagnostic and status program (for reporting bugs and re-calibrating the device when necessary) and the software portal from whence most Leap-friendly apps will come.
While executing the hardware correctly is surely of great import, the Leap is a platform that's only as good as the applications built for it. Which is why the company has spent so much time ingratiating itself with developers through an extended beta and created a purpose-built portal, called Airspace, in which to feature applications built for Leap. As we noted when we first saw Airspace demoed, it's a bifurcated portal composed of the Airspace Store on the web (where you acquire new apps) and the local Airspace Home (a launcher for any and all Leap-compatible apps). When you "buy" an app in the Airspace Store, Home detects that purchase and proceeds to download it automatically.
As of this writing, there are 54 applications built to run on Windows 7 and 8 machines and 58 apps for Macs running OS X 10.7 or higher. Nine of those apps are Windows exclusives, and 14 applications are Mac-only, with one app, called Touchless, having separate, but functionally identical versions for each (more on that later). Naturally, with such a large library of software at launch, we were unable to test every app in the Airspace Store. However, we did spend time with quite a few apps for both Windows and OS X.
Mac user experience
While the Airspace software felt welcoming and polished, things took a turn for the worse when we launched the pre-installed Orientation app, meant to familiarize users with the size of the gesture sandbox provided by the device and to serve as a general introduction to how Leap works. Orientation begins with a screen where a section of 3D space is marked out by a wireframe border and filled with a sort of luminous confetti. That confetti moves as if suspended in water, and it changed from white to glowing yellow and orange hues as we virtually swept our hands through it. Next, we were prompted to draw glowing white marks using our fingers, and, finally, we were shown a futuristic animated wireframe of our hands that included the individual joints of our fingers and tracked our movements. So far, so good.
Unfortunately, as we moved our hands around, our virtual fingers and thumbs disappeared and reappeared spontaneously; our wrists twitched some from side to side; and even slow, deliberate attempts to rotate our hands from palm up to palm down caused numerous detection failures. Not the most confidence-inspiring way to start off our Leap experience.
However, our faith was restored by several of the apps we tested. It's clear that, right now, the majority of folks building for the Leap are all about creative outlets, particularly gaming and music making. There's Boom Ball (think BrickBreaker in 3D), which works pretty much as you'd expect: you move around your extended finger, which corresponds to a digital paddle, and can control its pitch and yaw for finely tuned ricochet-angle control. Cut the Rope (a Mac-exclusive title for now) works as it does everywhere else, only you're swiping through thin air instead of on a screen. In Balloon Buzz, your bee avatar tracks to your fingertip and you pop balloons as they appear onscreen. All three of these games largely feature similar mechanics to touchscreen games, and the Leap performed admirably with all of them. The controller tracked our fingers precisely, and input dropped only sporadically, largely due to our own excitement causing our movements to become frenetic, or exiting the Leap's functional viewing area.
Dropchord is a wholly new gaming entity (for this editor, at least). In brief, it's a musical game that provides dazzling (if potentially seizure-inducing) visuals and requires players to use two hands to control dual points that slide along the circumference of a circle. A line connects those two points and players must bring that line in contact with orbs that appear within the circle to score and advance within the game. The controls here are simple, and since they're limited in scope, we had nary a problem -- our failures in the game were due mainly to lack of skill.
Not all our gaming experiences were positive, however. Digit Duel is a gunslinger-dueling title with pretty hand-drawn-style graphics, where you draw by forming your hand into the shape of a gun and flicking your finger up to shoot. We struggled mightily getting the game to recognize when we wanted to fire, and aiming was -- forgive the pun -- a crapshoot. Vitrun Air, a Marble Madness-style game where you move your hand forward to move and left or right to steer, suffered from similar control glitches -- the game would often fail to recognize our steering input, sending us falling off the course to our doom. Lastly, there's Block54, a digital Jenga-esque tower game requiring players to carefully remove blocks without causing the tower to topple. Control inputs were accurate for the most part, but we struggled to get the in-game camera placed at an optimal angle to allow for the removal of blocks, and positioning the virtual paddles used to remove blocks proved extremely difficult. Also, despite the fact that the game recommends using one hand to play, we found it impossible to get the angle correct when trying to grab blocks with one hand, and had far better luck using a two-handed approach (though our previous statements about the game's difficulty still stand).
In addition to games, there's a wide selection of music-making apps. AirHarp is exactly what you think it is, letting users strum away on a series of digital strings, while moving your fingers towards the screen increases the reverb. AirHarp also helped us acclimate to working with our hands in space -- it forced us to practice hovering and touching with more precision, so that we didn't always just scrape our finger along sequential harp strings. We did become more adept at this, but never to the point where we achieved the desired action 100 percent of the time. Chordion Conductor, meanwhile, is a genius little app for crafting songs using a variety of tempo, timbre, instrument and other settings. Plus, it has an Arpeggiator mode that automatically assembles notes in a melodic fashion as your fingers flit over digital keys. With the Arpeggiator turned on, we found it easy to create pleasing tunes. Truly, Airspace has some useful tools for the budding Mozart in your life.
Aside from games and music makers, several offerings in the Airspace Store are closer to demo "fluff" than actual programs. Flocking and Gravilux, for example, are straight eye candy. In Flocking, the tips of any extended fingers are represented as glowing orange orbs in an underwater environment, and those orbs cause hundreds of digital fish to swim around them in unison. Similarly, Gravilux is essentially a physics engine demo that displays thousands of tiny particles (users can choose their color and size) in a black environment -- those particles were attracted to the tips of our fingers and swirled around them as we waved our phalanges about. In both apps, the fluidity of the animations was impressive, and it's certainly cool seeing all those objects reacting to our hands, but we tired of both after a few minutes.
The other major category of apps available is educational. Cyber Science 3D lets you pull apart a human skull to identify the bones that comprise it and Frog Dissection lets you, well, dissect a digital frog (along with providing plenty of info about the amphibian's biology). Exoplanet lets you virtually explore the known universe and Molecules provides an up-close look at the molecular makeup of various compounds. In each of these, controls are rudimentary and fairly simple, but you can see the potential of the z-axis, pitch and yaw controls that the Leap provides -- it allowed us to easily manipulate three-dimensional digital objects and see them from all angles in a way we've never been able to before.
Windows user experience
Setup on our Windows machine was largely the same as it was for Mac, so we won't rehash the process here. Once we did get set up on our Windows 8 machine, however, we skipped past the fun titles in the app store and went straight for the serious stuff, starting with Touchless for Windows (there's an identical app built for Mac as well). Judging from its title image, which shows a finger navigating Windows 8's tile-based UI, we wondered whether this might offer an alternative to using the mouse. Heck, it could potentially even bring Windows 8 on the desktop PC more in line with the fluidity of the operating system on a touchscreen device. Alas, it wasn't to be.
Desktop control relies on dividing 3D space into two separate zones: one closer to your body, which is for "hovering," and one closer to the display, which is for "touching." In other words, it's just like hovering with a stylus before making contact with the screen on a Wacom tablet or Galaxy Note -- and hence it sounds like it should be intuitive. However, in practice we found that every time we moved a finger towards the computer monitor, the cursor drooped on the vertical axis, causing a mishit. This is because it's very hard to prevent your index finger from dropping slightly as it moves away from your body -- an inevitable consequence of the human elbow joint. Although practice would probably have improved the situation, we gave up after about 20 minutes due to its fairly steep learning curve and an encroaching sense that our time-limited existence on this beautiful planet was ebbing away.
Things improved when we shifted to Corel Painter Freestyle, which allows you to select different colors or brushes simply by hovering over a button for a few seconds. In this app, you only "touch" when you want to engage the brush on the paper, which avoids the need for precise button selections and therefore makes things easier. So long as you go for a masterpiece in the modernist style, with big and abstract strokes, it's a genuinely impressive experience. That's due to the way the software detects your movements on so many different axes, not just the position of your finger on the page, but also its orientation, which -- for example -- controls the directional flow of paint from your spray gun. The strokes on the screen might look messy, but they perhaps look more organic than what an inexperienced person could achieve with a Wacom stylus.
It was also annoying that the sensor often saw a thumb as a finger, even when we never intended for it to be registered. The only reliable way to prevent this was to tuck the thumb behind our bunched-up fingers, so that it couldn't protrude -- something that has felt instinctively wrong and unnatural ever since our first fistfight in the schoolyard.
Generally, although our control over the device did improve with time, it never became precise enough to allow for navigation of the Windows (or Mac) environment, in either the desktop or the modern UI -- and that was a huge blow to the daily usability of the Leap Motion controller.
All is not lost, however. Software updates could conceivably grant more control over how the device responds to our gestures -- perhaps by allowing us to set the sensitivity of different axes independently and saving these settings as profiles -- in order to minimize the impact of naturally arced motions. Perhaps some kind of thumb rejection is in order as well, to prevent us from having to tuck it inside our fist.
The Leap Motion did receive one update while we toyed with it, so we know its makers are there in the background, working on improvements -- there's just no guarantee as to whether or when they'll really deliver a "fix" for these issues.
All in all, the Leap Motion controller is more about potential than anything else. While it provides a new means for computational control unlike anything else we've seen, it's clear that it's not cut out to replace a touchscreen or mouse as a primary input device. Not yet, anyway. Some developer may well figure out a way to take full advantage of the Leap's capabilities with a novel UI, but for now, it's best suited for creative pursuits, not productivity. The initial software library for Leap is relatively limited, but as the number of folks with Leap controllers grow, so will the amount of attention it'll receive from developers. And, there are enough apps in the Airspace Store that most folks will find at least a few to their liking. Eighty bucks for a glimpse of what could be the future of computer controls? Not a bad deal, but if you do dive in, we'd advise you think of it as an entertainment expense, not a business one.
Sharif Sakr contributed to this review.