Getting Started with the Leap Motion SDK
Positional tracking
At the top of this post, you can see some of the positional tracking data available through the API, as well as how it’s organized. Every tracked entity in the Leap Motion interaction space falls within a hierarchy that starts with the hand. A Hand object includes:
- palm position and velocity
- direction and normal vectors
- orthonormal basis
Fingers
- tip position and velocity
- direction vector
- orthonormal basis
- length and width
Bones
- joint positions
- orthonormal basis
- length and width
Arm
- wrist and elbow positions
- direction vector
- orthonormal basis
- length and width
Pointable Tools
- tip position and velocity
- direction vector
- orthonormal basis
- length and width
Motions and gestures
Motions are continuous hand movements – estimates of how the position of tracked objects (hands, fingers, and tools) change over time. These consist of translation, rotation, and scale. Comparing any two frames containing the same hand allows you to compute the change in motion through time. By mapping motions and position data to their applications, developers havecontrolled flying drones,conducted orchestras, anddesigned art installations.
Gesturesare movement patterns that can be used to trigger certain actions. The Leap Motion API includesswipe,circle, andtapgestures, which are emitted as event objects in frames when recognized. You can use gestures toswipe through recipesor twirl your finger towatch videos.
V2 tracking beta
With the v2 tracking beta, our API is now able to provide a wide range ofadditional tracking data, including left vs. right hands, tracking confidence values, as well as grab and pinch strength. Finger tracking is now persistent (so that each hand always has five fingers), digit types are identified (thumb, index, middle, ring, and pinky), and individual bones and joints are tracked.
Diagnostic visualizer
Whether you’re testing an app or just want to see the tracking data in action while you wiggle your fingers, theDiagnostic Visualizeris a great resource for any developer. Toggle different settings (press ‘H’ to see all options) to get a feel for the Leap Motion tracking system.
