Pohung Chen, Leap Motion
Pohung Chen is Leap Motion's "Games Guy," building video games and other exciting concepts for the hand-and-finger sensor device.
With numerous notable titles now available for the Leap Motion, including motion-controlled versions of Cut the Rope and Fruit Ninja, plus titles like Double Fine's Dropchord and Flow Studio's Midnight, I asked Chen for his own take on what the best and worst practices for motion control are.
"Motion controls are pretty different from traditional methods of digital input," he says. "We are so used to binary actions: keys, buttons, mouse clicks, touch taps, etc., it can be difficult to think of good ways to design for motion control, which by nature is a very analog and continuous thing."
As a result, Chen says that most games do not translate well into motion controls -- when a developer tries to force motion controls onto existing games, it regularly ends up feeling clumsy and a poor experience for players.
"When building a motion control game, it's best to think about the core input interaction first," he continues. "Ask yourself: What is the player trying to do? What is the easiest and most natural way to use your hands, fingers, body, etc. to interact with your game? Make sure the core input interaction is good first before building game mechanics on top of it. If the core interaction sucks, the game will not be good. It'll be like trying to play StarCraft with just an Atari 2600 controller."
And conversely, trying to attach too many discrete actions to a motion control game is a common mistake that Chen sees. "Developers are used to the keyboard, which is really good at distinguishing between a lot of different discrete input (keys)," he says. "Unfortunately, it's very easy for motion control systems to mistake one action for another (if you're trying to discretize your input), so that ends up being a not very good experience for the user."
In terms of haptics technology, Chen notes that the tech available on a consumer level is still rather primitive, given that controller vibration is the only haptics option available to the majority of players.
"Valve is doing new haptics with their Steam Controllers, and there's some research on how to use ultrasonic waves for in-air haptic feedback, but consumer technology is still pretty far out from reaching out and feeling an object or having physical resistance," he notes.
"Because of this limitation, a lot of motion control mappings to real-life analogs with haptic feedback can feel really strange (this is why lightsaber duels won't feel quite right for a while). Since we don't have haptics, visual and audio feedback for what you're doing is incredibly important. This is anything from changing the color of a cursor to indicate a gesture, or lights/shadows to show 3D position of hands/fingers in a virtual scene."
Elsewhere, motion control developers need to keep in mind that connecting real-life movements and analogies up as closely as possible with video game motion controls can often prove very limiting.
"Despite all the generic first person shooter/person in a cockpit style games there are on the Oculus Rift, there's still stuff like Dumpy: Going Elephants (from DePaul University) and SoundSelf (Robin Arnott, Evan Balster)," Chen reasons. "With the Leap Motion Controller, you can use it to push physical stuff around, or you could map properties of the hand to MIDI output and hook it up to Ableton Live to expressively perform music -- the possibilities with new hardware form factors are endless, and I'm really excited to see what kind of creative stuff people come up with in the next couple of years with new hardware."
When it comes to deciding on whether a motion control concept works, Chen suggests that developers should begin by considering a wide range of potential control schemes for an idea, and then eliminate those that don't entirely work until you've left with the best choice.
"Once you find something that works well, and this is largely by feel, one thing that's super useful is to get someone new to try out what you've built," he says. "Don't explain anything, and watch what they try to do. Sometimes you'll get ideas for how to come up with better control schemes by just watching people struggle with what you’ve built."
And for new studios considering motion controls, Chen says that "the best experiences are designed from the ground up with motion control in mind."
"As for side-features or putting in motion controls after a game is already well into development, it is better to focus on doing a few things well than trying to do everything at once," he adds. "I think motion control is still in its infancy. As the technology gets better and more developers experiment with new and interesting models of interaction, we'll start to see some really cool stuff in this space."