OpenXR

The SenseGlove Unreal Engine Plugin has provided OpenXR-compatible hand tracking by implementing XR_EXT_hand_tracking since v2.1.0.

Typically a user does not need to know anything about OpenXR to use the plugin, so this section of the handbook is for advanced users who are looking for a way to directly consume the OpenXR data coming directly from either a SenseGlove device or if enabled in the plugin settings from hand-tracking.

Since the SenseGlove Unreal Engine Plugin registers itself as an OpenXRHandTracking motion controller device it becomes a hand-tracking provider for Unreal Engine, thus the OpenXR data from SenseGlove could always be retrieved from the Unreal Engine's IXTrackingSystem with one caveat. The caveat is if another OpenXR-compatible hand-tracking plugin, e.g. Epic's own OpenXRHandTracking, is enabled simultaneously it's not guaranteed that the FXRMotionControllerData and FXRHandTrackingState structs retrieved from the IXTrackingSystem::GetMotionControllerData() and IXTrackingSystem::GetHandTrackingState() methods are coming from SenseGlove, as these methods return the first hand-tracking plugin they could find. Thus, SenseGlove provides its own implementation of GetMotionControllerData() and GetHandTrackingState() which guarantee the retrieved FXRMotionControllerData or FXRHandTrackingState are coming from the SenseGlove Unreal Engine Plugin; and this is the preferred way to that.

note

In order to retrieve the latest FXRMotionControllerState available, The SenseGlove Unreal Engine Plugin provides an alternative implementation for IXTrackingSystem::GetMotionControllerState() as well . However, since this method does not rely on the OpenXRHandTracking provider, it may become redundant. As a result, we might consider removing this functionality in future updates in favor of the one that Unreal Engine provides.

important

Unreal Engine versions 5.2, 5.3, and 5.4 are limited to FXRMotionControllerData since at the time of their release no FXRHandTrackingState was available. Also please keep in mind that, while FXRMotionControllerData is pretty much usable and functional in Unreal Engine 5.5, it is recommended to utilize FXRHandTrackingState instead. This is because this version of UE has deprecated FXRMotionControllerData in favor of the FXRMotionControllerState and FXRHandTrackingState structs. Prior to version 5.5, FXRMotionControllerData handled both motion controller and hand tracking data. From 5.5 onward, these responsibilities have been separated into the two distinct structs, providing clearer and more specialized handling of each.

In the next sections we'll see:

How we can directly consume the FXRMotionControllerData on UE 5.2, 5.3, 5.4, and 5.5 to draw and animate debug virtual hands in both Blueprint and C++.
How we can directly consume the FXRHandTrackingState on UE 5.5 to draw and animate debug virtual hands in both Blueprint and C++.

The SenseGlove Unreal Engine Handbook

OpenXR