Tracking ModelΒΆ

The Leap Motion API defines a class representing each of the primary tracked objects.


The LeapFrame object is essentially the root of the data model and provides access to all the tracked entities. A new LeapFrame is created at each update interval.

The frame contains lists of the hands and fingers tracked in that frame. (You can also get the fingers for a specific hand from the relevant LeapHand object.)

LeapController *controller = [[LeapController alloc] init];
// wait until Controller.isConnected() evaluates to true

LeapFrame *frame = [controller frame:0];
NSArray *hands = frame.hands;
NSArray *pointables = frame.pointables;
NSArray *fingers = frame.fingers;
NSArray *tools =;

See Frames


The LeapHand object describes the position and orientation of a hand, tracks its motion between frames and contains lists of the fingers associated with that hand.

// hand is a Hand object
NSArray *pointables = [hand pointables];
NSArray *fingers = [hand fingers ];

See Hands

LeapArm LeapArm objects describe the position, direction, and orientation of the arm to which a hand is attached. Arms can only be accessed through the LeapHand object.
LeapPointable, LeapFinger

LeapPointable objects define the basic characteristics common to fingers. The LeapFinger class extends LeapPointable with additional information specific to those entities.

if (pointable.isTool) {
    LeapTool *tool = (LeapTool*)pointable;
} else {
    LeapFinger *finger = (LeapFinger*)pointable;

See Fingers

LeapBone LeapBone object represent the position and orientation of a bone. The tracked bones include the metarcarpals and phalanges of the fingers (and thumb).
LeapImage LeapImage objects provide the raw sensor data and calibration grid for the Leap Motion cameras. (Not available through the WebSocket server.)
Utility Classes

The LeapVector class describes points and directions. The LeapVector class also provides several useful math functions for working with vectors.

Likewise, the LeapMatrix class represents things like rotations and other transforms returned by some functions in the API.

The LeapInteractionBox class provides functions to help map a rectilinear portion of the Leap Motion controller’s field of view to either 2D screen space or 3D space. See Leap_Touch_Emulation.