Meta Hand Tracking Frequency Hint OpenXR feature

Unity OpenXR provides support for the XR_META_hand_tracking_frequency_hint extension. This extension augments the XR_EXT_hand_tracking extension and allows applications to provide a frequency hint to the runtime to indicate the desired hand tracking update frequency. Applications can suggest that the runtime use a higher tracking frequency when needed for low-latency scenarios, or use the default frequency for normal operation.

Note

The frequency hint is a suggestion only. The runtime may choose to ignore the hint based on user preferences, system constraints, power management policies, or other considerations. Applications should not rely on the runtime honoring the hint and should be prepared to handle hand tracking data at any supported frequency.

Prerequisites

To use the Meta Hand Tracking Frequency Hint feature, your project must meet the following requirements:

Enable the feature

To enable the Meta Hand Tracking Frequency Hint feature:

  1. Go to Project Settings > XR Plug-in Management > OpenXR.
  2. Enable Meta Hand Tracking Frequency Hint in the feature list.

The Hand Tracking Subsystem feature must also be enabled or the frequency hint feature has no effect.

Feature settings

Property Description
Frequency Hint The frequency hint to apply when the OpenXR session starts. Can be changed at runtime using XRHandSubsystem.TryUpdateConfiguration.

To access this property, click the gear icon next to Meta Hand Tracking Frequency Hint in Project Settings > XR Plug-in Management > OpenXR.

Meta Hand Tracking Frequency Hint settings
Feature settings for Meta Hand Tracking Frequency Hint

Frequency hint values

Value Description
Default Suggests the runtime use its default hand tracking frequency. This is typically the most power-efficient frequency that provides adequate tracking quality for general use cases.
High Suggests the runtime use a higher hand tracking frequency when possible. This may provide more responsive tracking for performance-critical applications, but at higher frame rates the effectiveness of temporal smoothing algorithms is reduced, which can result in increased jitter and less visually smooth hand tracking.

Change the frequency hint at runtime

You can change the frequency hint while your application is running by calling TryUpdateConfiguration on the hand subsystem with a MetaHandTrackingFrequencyHintConfig. The change takes effect immediately if an OpenXR session is active. The method returns true if the native call succeeded, or false if it failed. You can read the current hint with TryGetConfiguration.

The following example shows how to request high-frequency hand tracking at runtime:

using UnityEngine;
using UnityEngine.XR.Hands.OpenXR;

var subsystem = HandTracking.subsystem;
if (subsystem != null)
{
    bool success = subsystem.TryUpdateConfiguration(new MetaHandTrackingFrequencyHintConfig
    {
        frequencyHint = MetaHandTrackingFrequencyHint.High,
    });
    if (!success)
        Debug.LogWarning("Failed to set frequency hint to High.");
}

Important considerations

  • The frequency hint is advisory. The runtime may choose to maintain the default frequency if, for example, power or thermal constraints prevent higher update rates.
  • The frequency hint applies per-session, not per-hand. Both hands share the same tracking frequency.
  • Requesting high frequency may increase power consumption. Consider reverting to the default hint when high-frequency tracking is no longer needed.
  • If the extension is not supported by the current device or runtime, the feature is disabled and hand tracking continues to operate normally at the default frequency.

Additional resources