Tracking ModelΒΆ

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

Frame HandList Hand FingerList PointableList ToolList Finger Pointable Tool GestureList Gesture CircleGesture SwipeGesture KeyTapGesture ScreenTapGesture Bone ImageList Image Arm

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

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

Controller controller = new Controller ();
// wait until Controller.isConnected() evaluates to true

Frame frame = controller.Frame ();
HandList hands = frame.Hands;
PointableList pointables = frame.Pointables;
FingerList fingers = frame.Fingers;
ToolList tools = frame.Tools;

See Frames


The Hand 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
PointableList pointables = hand.Pointables;
FingerList fingers = hand.Fingers;

See Hands

Arm Arm objects describe the position, direction, and orientation of the arm to which a hand is attached. Arms can only be accessed through the Hand object.
Pointable, Finger, Tool

Pointable objects define the basic characteristics common to fingers and tools. The Finger and Tool classes extend Pointable with additional information specific to those entities.

if (pointable.IsTool) {
    Tool tool = new Tool (pointable);
} else {
    Finger finger = new Finger (pointable);

See Fingers

Bone Bone object represent the position and orientation of a bone. The tracked bones include the metarcarpals and phalanges of the fingers (and thumb).

The Gesture class and its subclasses represent a snapshot of one of the four gestures recognized by the Leap Motion software.

See Gestures

Image Image objects provide the raw sensor data and calibration grid for the Leap Motion cameras. (Not available through the WebSocket server.)
Lists of Tracked Objects

The Frame and Hand objects contain lists of the other tracked objects.

HandList, PointableList, FingerList, and ToolList classes provide a few convenience functions for filtering the list members. For example, the frontmost() function returns the item that is the most forward in the Leap Motion controller’s field of view (smallest z value).

Utility Classes

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

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

The InteractionBox 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 Touch Emulation.