Hand Mesh Data

This feature provides access to hand mesh geometry through the XR_FB_hand_tracking_mesh OpenXR extension. Hand mesh data includes vertex positions, normals, UVs, triangle indices, joint bind poses, and bone weights for skinned hand mesh rendering.

This feature works in conjunction with the Hand Tracking Subsystem feature. When you enable both features, hand mesh data is available through the XRHandSubsystem.TryGetMeshData API.

In OpenXR Project Settings, this feature appears as Meta Quest: Hand Mesh Data and is available for Android and Standalone build targets.

Note

The target XR platform must support the XR_FB_hand_tracking_mesh OpenXR extension. This extension is currently supported on Meta Quest and Android XR devices. The hand mesh data is immutable for the lifetime of the OpenXR instance. Once retrieved, the geometry doesn't change between frames.

Requirements

• Install the XR Hands package (version 1.9.0 or later).
• Enable the Hand Tracking Subsystem OpenXR feature.
• On Android, the application must have hand tracking permissions. When you enable this feature, the build hook configures the Android manifest automatically by adding:
  • <uses-permission android:name="android.permission.HAND_TRACKING" />
  • <uses-permission android:name="com.oculus.permission.HAND_TRACKING" />
  • <uses-feature android:name="oculus.software.handtracking" android:required="false" /> At runtime, request the permission that matches the target platform: android.permission.HAND_TRACKING on Android XR devices, or com.oculus.permission.HAND_TRACKING on Meta Quest devices.

Enable the Hand Mesh Data feature

To use hand mesh data, enable the feature in the OpenXR Project Settings:

1. Open the Project Settings window (menu: Edit > Project Settings).
2. Expand the XR Plug-in Management section, if necessary.
3. Select the OpenXR area under XR Plug-in Management.
4. Choose the Platform Build Target from the tabs along the top of the OpenXR settings page.
5. Check the box next to Meta Quest: Hand Mesh Data (in the All Features group) to enable the feature.
6. Ensure the Hand Tracking Subsystem feature is also enabled.

Retrieve hand mesh data

Use XRHandSubsystem.TryGetMeshData to retrieve mesh data for both hands:

var queryParams = new XRHandMeshDataQueryParams
{
    allocator = Allocator.Temp
};

if (subsystem.TryGetMeshData(out var result, ref queryParams))
{
    using (result)
    {
        // Access left hand mesh data
        var leftHand = result.leftHand;
        if (leftHand.positions.IsCreated)
        {
            // Use leftHand.positions, leftHand.normals, leftHand.uvs,
            // leftHand.indices, leftHand.bonesPerVertex, leftHand.boneWeights
        }

        // Access right hand mesh data
        var rightHand = result.rightHand;
        // ...
    }
}

Important

If TryGetMeshData returns true, you're responsible for disposing the result. Use a using statement or call Dispose() on the XRHandMeshDataQueryResult when done.

Available data

The XRHandMeshData struct provides the following data when available:

Property	Type	Description
positions	NativeArray<Vector3>	Vertex positions in session space.
normals	NativeArray<Vector3>	Vertex normals.
uvs	NativeArray<Vector2>	Texture UV coordinates.
indices	NativeArray<int>	Triangle indices into the vertex arrays.
bonesPerVertex	NativeArray<byte>	Number of bones influencing each vertex.
boneWeights	NativeArray<BoneWeight1>	Bone weights for skinned mesh rendering.

Use TryGetRootPose to retrieve the root pose for positioning the mesh, and TryGetJointBindPoseMatrix to retrieve bind poses for individual joints.

Check each array's IsCreated property before use, because some data is unavailable in certain cases.

Validation

When enabled, the feature includes a project validation rule that checks whether the Hand Tracking Subsystem feature is also enabled. If the Hand Tracking Subsystem isn't enabled, the validation system displays a warning with an automatic fix option.