This interface encapsulates the core capabilities common to all hand tracking solutions supported by the Interaction SDK. Where possible, you should use this interface instead of concrete alternatives such as Hand, which are less general and portable.

Properties

Handedness Handedness[Get]

Indicates whether the tracked hand is Handedness.Left- or Handedness.Right-handed.

bool IsConnected[Get]

Indicates whether hand tracking is available and has valid data.

Note that, because this reflects both the general availability and present validity of hand tracking data, this value can vary from frame to frame depending on whether the system is currently able to track the hand. This is a valid API to check in order to determine whether up-to-date hand tracking is available at a given moment.

bool IsHighConfidence[Get]

Indicates whether the system has high confidence in the validity of its most recent hand tracking data.

In order for this value to be true, IsConnected and IsTrackedDataValid must also be true.

bool IsDominantHand[Get]

Indicates whether the current hand is the dominant hand.

The availability of this feature depends on whether or not the platform provides a way to determine whether the user is left- or right-handed.

float Scale[Get]

Indicates the detected scale of the tracked hand relative to the default tracked hand size.

bool IsPointerPoseValid[Get]

Checks whether a valid "pointer pose" is currently available.

See GetPointerPose(out Pose) for details on what a pointer pose is.

bool IsTrackedDataValid[Get]

Indicates whether the hand is currently tracked such that tracking poses are available for the hand root and finger joints.

Note that this property being true does not necessarily mean that a valid pointer pose is available; IsPointerPoseValid may be false while valid tracking data is available.

int CurrentDataVersion[Get]

Indicator which is incremented every time new tracked hand data becomes available.

Events

Action WhenHandUpdated

Event indicating that CurrentDataVersion has been incremented and thus the hand can be queried for potentially new data.

Member Functions

bool GetFingerIsPinching

( HandFinger finger )

Checks whether a particular finger is considered to be pinching.

How a given finger is determined to be pinching is an implementation detail which can vary by finger/platform and is not part of the contract of this method, which merely provides a unified way to query for the semantic concept of a "pinch".

Parameters

finger

The finger to check for pinching behavior

Returns

Whether or not the requested finger is considered to be pinching

bool GetIndexFingerIsPinching ( )

A convenience method to check for the most commonly-desired pinching behavior.

Calling this method is equivalent to calling GetFingerIsPinching(HandFinger) with the argument HandFinger.Index.

Returns

Whether or not the index finger is considered to be pinching

bool GetPointerPose

( out Pose pose )

Attempts to return a valid "pointer pose" for the hand.

A "pointer pose" is a world-space pose (position and orientation) intended to be used as a directional input, conceptually comparable to "pointing at something." However, the nature of this pose and its relationship to the hand are not part of the contract of this method; it may or may not correspond to a "direction of pointing," and in many implementations it corresponds more closely to a "direction of reaching out." These details can vary, but in all cases this method provides a unified way to query for the semantic concept of a "pointer."

Parameters

pose

A valid world-space pointer pose if one could be calculated, identity otherwise

Returns

True if the pose argument was populated with a valid pointer pose, false otherwise

bool GetJointPose

( HandJointId handJointId,

out Pose pose )

Attempts to return the world-space pose of the requested hand joint.

Parameters

handJointId

The joint for which the pose is being requested

pose

A valid world-space joint pose if one is available, identity otherwise

Returns

True if the pose argument was populated with a valid joint pose, false otherwise

bool GetJointPoseLocal

( HandJointId handJointId,

out Pose pose )

Attempts to return the pose of the requested hand joint in "local" space.

This "local" space is loosely defined and can vary by platform (in some implementations, each joint is relative to a given parent joint), so the exact nature of what is returned by this method is not guaranteed. In general, it is recommended to use GetJointPose(HandJointId, out Pose) or GetJointPoseFromWrist(HandJointId, out Pose) instead where possible.

Parameters

handJointId

The joint for which the pose is being requested

pose

A valid "local" space joint pose if one is available, identity otherwise

Returns

True if the pose argument was populated with a valid joint pose, false otherwise

bool GetJointPosesLocal

( out ReadOnlyHandJointPoses localJointPoses )

Retrieves all "local" space joint poses for this hand.

The values returned by this method are the same as those returned by calling GetJointPoseLocal(HandJointId, out Pose) repeatedly, but as a batched query this method can be more efficient if many joint poses are needed.

Parameters

localJointPoses

The array of all "local" joint poses if available, or an empty array otherwise

Returns

True if the poses collection was correctly populated, false otherwise

bool GetJointPoseFromWrist

( HandJointId handJointId,

out Pose pose )

Attempts to return the pose of the requested hand joint in wrist space.

Wrist space is strongly defined as a transform space located and oriented according to HandJointId.HandWristRoot. This space is of uniform scale across hand sizes, meaning all tracked hands are the same size in wrist space, and wrist space itself must be multipled by Scale in order to correctly reflect the observed size of the tracked hands in world space.

Parameters

handJointId

The joint for which the pose is being requested

pose

A valid wrist space joint pose if available, false otherwise

Returns

True if the pose argument was populated with a valid joint pose, false otherwise

bool GetJointPosesFromWrist

( out ReadOnlyHandJointPoses jointPosesFromWrist )

Retrieves all wrist space joint poses for this hand.

The values returned by this method are the same as those returned by calling GetJointPoseFromWrist(HandJointId, out Pose) repeatedly, but as a batched query this method can be more efficient if many joint poses are needed.

Parameters

jointPosesFromWrist

The array of all wrist space joint poses if available, or an empty array otherwise

Returns

True if the poses collection was correctly populated, false otherwise

bool GetPalmPoseLocal

( out Pose pose )

Attempts to return the pose of the palm in "local" space.

This "local" space is loosely defined and can vary by platform; in some implementations, it can be considered for this method in particular to be synonymous with wrist space.

Parameters

pose

The "local" palm position and orientation if available, identity otherwise

Returns

True if the pose argument was populated with a valid palm pose, false otherwise

bool GetFingerIsHighConfidence

( HandFinger finger )

Queries whether the tracking data for a particular finger is high- or low-confidence.

Parameters

finger

The finger to be checked for high-confidence tracking data

Returns

True if the system is confident in its tracking data for the requested finger, false otherwise

float GetFingerPinchStrength

( HandFinger finger )

Queries the strength with which a particular finger is considered to be pinching.

"Strength" in this case is an indication of how similar or different the finger's pose is to what could be considered a pinch; a finger with its tip far from the thumb will likely have a pinch strength at or near 0, while a finger with its tip touching the thumb will likely have a pinch strength at or near 1.

Parameters

finger

The finger to be checked for pinch strength

Returns

A number from 0 to 1 indicating how far or close, respectively, the finger is from pinching

bool GetRootPose

( out Pose pose )

Attempts to retrieve the pose of the wrist joint in world space.

This is a convenience method and is identical to calling GetJointPose(HandJointId, out Pose) with the argument HandJointId.HandWristRoot.

Parameters

pose

A void world space pose for the wrist joint if available, identity otherwise

Returns

True if the pose argument was populated with a valid joint pose, false otherwise

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