Arm Class Reference

The Arm class represents the forearm. More...

Inherits Bone.

Public Types
enum	BoneType
	Enumerates the names of the bones. More...

Public Member Functions
	Arm ()
	Constructs a default Arm object. More...
	Arm (Vector elbow, Vector wrist, Vector center, Vector direction, float length, float width, LeapQuaternion rotation)
	Constructs a new Arm object. More...
bool	Equals (Arm other)
	Compare Arm object equality. More...
bool	Equals (Bone other)
	Compare Bone object equality. More...
override string	ToString ()
	A string containing a brief, human readable description of the Arm object. More...

Public Attributes
Vector	Center
	The midpoint of the bone. More...
Vector	Direction
	The normalized direction of the bone from base to tip. More...
float	Length
	The estimated length of the bone in millimeters. More...
Vector	NextJoint
	The end of the bone, closest to the finger tip. More...
Vector	PrevJoint
	The base of the bone, closest to the wrist. More...
LeapQuaternion	Rotation
	The orientation of this Bone as a Quaternion. More...
Bone.BoneType	Type
	The name of this bone. More...
float	Width
	The average width of the flesh around the bone in millimeters. More...

Properties
LeapTransform	Basis [get]
	The orthonormal basis vectors for this Bone as a Matrix. More...
Vector	ElbowPosition [get]
	The position of the elbow. More...
Vector	WristPosition [get]
	The position of the wrist. More...

Detailed Description

The Arm class represents the forearm.

Member Enumeration Documentation

enum BoneType

stronginherited

Enumerates the names of the bones.

Members of this enumeration are returned by Bone::type() to identify a Bone object.

Since

2.0

Constructor & Destructor Documentation

Arm

(

)

Constructs a default Arm object.

Get valid Arm objects from a Hand object.

Arm arm = hand.Arm;

Since

2.0.3

Arm	(	Vector	elbow,
		Vector	wrist,
		Vector	center,
		Vector	direction,
		float	length,
		float	width,
		LeapQuaternion	rotation
	)

Constructs a new Arm object.

Parameters

elbow	The position of the elbow.
wrist	The position of the wrist.
center	The position of the midpoint between the elbow and wrist.
direction	The unit direction vector from elbow to wrist.
length	The distance between elbow and wrist in millimeters.
width	The estimated average width of the arm.
basis	The basis matrix representing the orientation of the arm.

Since

3.0

Member Function Documentation

bool Equals

(

Arm

other

)

Compare Arm object equality.

Boolean theSame = thisArm.Equals(thatArm);

Two Arm objects are equal if and only if both Arm objects represent the

exact same physical arm in the same frame and both Arm objects are valid.

Since

2.0.3

bool Equals ( Bone  other )

inherited

Compare Bone object equality.

Two Bone objects are equal if and only if both Bone objects represent the exact same physical bone in the same frame and both Bone objects are valid.

Since

2.0

override string ToString

(

)

A string containing a brief, human readable description of the Arm object.

String description = arm.ToString ();

Returns

A description of the Arm object as a string.

Since

2.0.3

Member Data Documentation

Vector Center

inherited

The midpoint of the bone.

Vector middle = bone.Center;

Returns

The midpoint in the center of the bone.

Since

2.0

Vector Direction

inherited

The normalized direction of the bone from base to tip.

Vector direction = bone.Direction;

Returns

The normalized direction of the bone from base to tip.

Since

2.0

float Length

inherited

The estimated length of the bone in millimeters.

float length = bone.Length;

Returns

The length of the bone in millimeters.

Since

2.0

Vector NextJoint

inherited

The end of the bone, closest to the finger tip.

In anatomical terms, this is the distal end of the bone.

Vector boneEnd = bone.NextJoint;

Returns

The Vector containing the coordinates of the next joint position.

Since

2.0

Vector PrevJoint

inherited

The base of the bone, closest to the wrist.

In anatomical terms, this is the proximal end of the bone.

Vector boneStart = bone.PrevJoint;

Returns

The Vector containing the coordinates of the previous joint position.

Since

2.0

LeapQuaternion Rotation

inherited

The orientation of this Bone as a Quaternion.

Returns

The Quaternion.

Since

2.0

Bone.BoneType Type

inherited

The name of this bone.

Bone.BoneType type = bone.Type;

Returns

The anatomical type of this bone as a member of the Bone::Type enumeration.

Since

2.0

float Width

inherited

The average width of the flesh around the bone in millimeters.

float width = bone.Width;

Returns

The width of the flesh around the bone in millimeters.

Since

2.0

Property Documentation

LeapTransform Basis

getinherited

The orthonormal basis vectors for this Bone as a Matrix.

The orientation of this Bone as a Quaternion.

Basis vectors specify the orientation of a bone.

xBasis Perpendicular to the longitudinal axis of the bone; exits the sides of the finger.

yBasis or up vector Perpendicular to the longitudinal axis of the bone; exits the top and bottom of the finger. More positive in the upward direction.

zBasis Aligned with the longitudinal axis of the bone. More positive toward the base of the finger.

The bases provided for the right hand use the right-hand rule; those for the left hand use the left-hand rule. Thus, the positive direction of the x-basis is to the right for the right hand and to the left for the left hand. You can change from right-hand to left-hand rule by multiplying the z basis vector by -1.

You can use the basis vectors for such purposes as measuring complex finger poses and skeletal animation.

Note that converting the basis vectors directly into a quaternion representation is not mathematically valid. If you use quaternions, create them from the derived rotation matrix not directly from the bases.

LeapTransform basis = bone.Basis;
Vector xBasis = basis.xBasis;
Vector yBasis = basis.yBasis;
Vector zBasis = basis.zBasis;

Returns

The basis of the bone as a matrix.

The Quaternion.

Since

2.0

Vector ElbowPosition

get

The position of the elbow.

Vector elbow = arm.ElbowPosition;

If not in view, the elbow position is estimated based on typical human anatomical proportions.

Since

2.0.3

Vector WristPosition

get

The position of the wrist.

Vector wrist = arm.WristPosition;

Note that the wrist position is not collocated with the end of any bone in the hand. There is a gap of a few centimeters since the carpal bones are not included in the skeleton model.

Since

2.0.3