Plugin/Handbook/src/getting-started/enabling-xr-ext-hand-tracking-vr-headsets/pcvr-mode/README.md

# Enabling XR_EXT_hand_tracking OpenXR Extension on VR Headsets in PCVR Mode

Starting from version [`v2.1.0`](../../../appendix/changelog.html#210---2024-08-16), the SenseGlove Unreal Engine Plugin requires the `XR_EXT_hand_tracking` OpenXR extension to function. If you are streaming your immersive 3D VR application from your PC to your VR headset, enabling `XR_EXT_hand_tracking` support, requires additional plugins and settings depending on the HMD's vendor or model.

## Enabling OpenXR Plugin and Disabling OpenXRHandTracking Plugin

Regardless of the type or vendor of the HMD you have in mind for development or deployment purposes, the `OpenXR` plugin is required as a prerequisite. Also, ensure the `OpenXRHandTracking` is disabled as it conflicts with the SenseGlove Unreal Engine Plugin since both implement the same `XR_EXT_hand_tracking` OpenXR extension.

Though [enabling the SenseGlove Unreal Engine Plugin](../../plugin-verify-version-enable/) should enable the `OpenXR` plugin automatically, it is recommended to ensure this plugin is enabled, and most importantly `OpenXRHandTracking` is disabled, by navigating to `Edit > Plugins` in the Unreal Editor menus.

![Enabling XR_EXT_hand_tracking OpenXR Extension on VR Headsets in PCVR Mode - Enabling OpenXR and OpenXRHandTracking Plugins](../enable-openxr-disable-openxrhandtracking-plugins.png "Enabling XR_EXT_hand_tracking OpenXR Extension on VR Headsets in PCVR Mode - Enabling OpenXR and OpenXRHandTracking Plugins")

The `OpenXRHandTracking` plugin implements the `XR_EXT_hand_tracking` OpenXR extension.

## Meta Quest

To set up `XR_EXT_hand_tracking` support on Meta Quest HMDs in PCVR mode, depending on your project requirements (e.g. whether you rely on the `Meta XR` plugin or not), additional setup steps are required.

## Meta Quest Link App

For Meta Quest headsets, enable the `Developer runtime features` under the `Settings > Beta` section inside the Meta Quest Link app:

![Meta Quest Link - Developer Runtime Features - Enabling XR_EXT_hand_tracking](meta-quest-link-developer-runtime-features.png "Meta Quest Link - Developer Runtime Features - Enabling XR_EXT_hand_tracking")

> [!IMPORTANT]
> Enabling `Developer runtime features` in the Meta Quest Link requires a
> [Meta Developer Account](https://developers.facebook.com/docs/development/register/).
> If you are not signed in using a Meta Developer Account, this option won't
> be shown to you inside Meta Quest Link.

> [!CAUTION]
> Streaming to Meta Quest headsets from SteamVR is no longer supported because
> the migration to OpenXR has caused controller offsets for Meta Quest HMDs to
> break on SteamVR. One possible reason is that
> [SteamVR lists `XR_FB_hand_tracking` as an unsupported feature](https://steamcommunity.com/app/250820/discussions/8/3121550424355682585/).
> Further investigation is needed to identify the exact underlying cause.

### Meta XR Plugin

> [!CAUTION]
> Please note that enabling the `Meta XR` plugin alongside the SenseGlove plugin
> will result in crashes or unexpected behavior. `Meta XR` plugin compatibility
> is being worked on and might be supported in the future.

## HTC VIVE

To set up `XR_EXT_hand_tracking` support on HTC VIVE HMDs in PCVR mode, additional plugins or configuration steps are required.

### OpenXRViveTracker Plugin

To enable VIVE Trackers support ensure the `OpenXRViveTracker` plugin is enabled by navigating to `Edit > Plugins` in the Unreal Editor menus. This plugin should be enabled, or wrist tracking won't function on VIVE devices at all.

![Enabling XR_EXT_hand_tracking OpenXR Extension on VR Headsets in PCVR Mode - Enabling OpenXRViveTracker Plugin](enable-openxrvivetracker-plugin.png "Enabling XR_EXT_hand_tracking OpenXR Extension on VR Headsets in PCVR Mode - Enabling OpenXRViveTracker Plugin")

The `OpenXRViveTracker` plugin implements the `XR_HTCX_vive_tracker_interaction` OpenXR extension which is necessary to use VIVE Trackers or to [emulate the VIVE Wrist Trackers as VIVE Trackers on Windows](#vive-business-streaming-app).

### VIVE Business Streaming App

For VIVE headsets relying on the VIVE Business Streaming application, ensure the Hand Tracking settings under `Input` are enabled and `XR_HTCX_vive_tracker_interaction` is enabled for VIVE Wrist Trackers by enabling `Emulate VIVE Wrist Tracker as VIVE Tracker`:

![VIVE Business Streaming - Hand tracking - Enabling XR_EXT_hand_tracking and Emulating VIVE Wrist Tracker as VIVE Tracker](vive-business-streaming-hand-tracking.png "VIVE Business Streaming - Hand tracking - Enabling XR_EXT_hand_tracking and Emulating VIVE Wrist Tracker as VIVE Tracker")

> [!NOTE]
> Tracking and accessing `FXRHandTrackingState` output from SenseGlove
> devices do not require Hand and Body Tracking to be enabled on the HMD device.
> Enabling this feature is only necessary if you wish to use hand-tracking as a
> fallback option when no glove is connected to your PC.

### SteamVR App

After enabling the [OpenXRViveTracker plugin](#openxrvivetracker-plugin) and [enabling `Emulate VIVE Wrist Tracker as VIVE Tracker` for VIVE HMDs relying on the VIVE Business Streaming](#vive-business-streaming-app), you need to perform one final setup in the SteamVR app for the SenseGlove Unreal Engine Plugin to be able to retrieve the correct wrist-tracking offsets. Once you have paired your VIVE Trackers or VIVE Wrist Trackers, navigate to `SteamVR Settings > Controllers > MANAGE TRACKERS` and make sure your left tracker is set to `LEFT FOOT` and the right tracker is set to `RIGHT FOOT`:

![SteamVR - Manage Trackers - Setting the motion source for left and right hands](steamvr-manage-trackers.png "SteamVR - Manage Trackers - Setting the motion source for left and right hands")

## SenseGlove Wrist Tracking Settings

Once you have set up everything, it's time to adjust the [SenseGlove Wrist Tracking Settings](../../setup-wrist-tracking-hardware/) inside the project-wide plugin's settings. For detailed information, please visit [the Wrist Tracking Hardware and HMD auto-detection configuration section](../../../plugin-configuration/plugin-settings/tracking/wrist-tracking/) as well.