Leap Motion’s Interaction Engine Lets You Get a Grip in VR

Launched back in 2012, Leap Motion first introduced us to their new way of interacting with computers in three dimensions. At the time, the Leap Motion sensor sat on your desk or was built into your keyboard, allowing for natural hand and finger movement tracking. This allowed you to gesture at your screen to scroll through webpages, pinch zoom, draw, play games and even sign digital documents. There was one thing — the device never really caught on.

But now the Leap Motion controller has found new life as a virtual reality hand tracker.


Connected to the front of a VR headset like the Oculus Rift, the latest version of Leap Motion does a great job of tracking your hand and finger movements so your hands can be represented by virtual ones in front of you. The only problem is that the game engines that most VR experiences are made with don’t treat your virtual hands any differently than they do any other virtual object. The normal behavior for when two objects hit each other is for them to bounce or move away from each other. So while these virtual hands are fine for pushing items or cradling them in your hand, they don’t let you pick up, hold, or throw objects.


Leap Motion is well aware of this problem and have announced a beta for what they are calling their Interaction Engine to help fix it. What the Interaction Engine does is allow certain objects to ignore the usual behavior of colliding with and moving away from your hands. Instead your virtual hands can pass into these objects and using natural gestures, let you grab, hold and throw objects around. While this seems less accurate, it allows for interactions with objects that more meet your expectations and are less frustrating. Other objects like buttons or doors that you may want to keep with their default collision behavior can be left unchanged.

Demos show improved results grasping, stacking and throwing objects in a natural looking way. This is an early beta of the engine with the company stating that it works well with cubes and spheres around 1-2 inches in size, but smaller and elongated objects are known to be problematic.

Currently no consumer VR headset has a built in hand tracking system using Leap Motion. The company does sell a “Universal VR Dev Bundle” that includes a mount compatible with the Oculus Rift and HTC Vive with a 15 foot cable extender. They also have an OSVR HDK with an integrated Leap Motion faceplate coming soon. Overall hand tracking can give you a more realistic feeling of presence than holding a motion controller and is something we hope to see more of in the future.

About the Scout

Rob Crasco

VR Influencer / Evangelist / Entrepreneur, named #5 VR influencer by, 10 years experience in virtual worlds, background in computer science and marketing.

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