XR Origin
Transform XR tracking data into the scene world space.
Read time 4 minutesLast updated 16 days ago
The XR Origin serves as the center of tracking space in an XR scene.
An XR Origin is a set of GameObjects and components that work together to transform XR tracking data into the scene world space.
The following topics discuss the XR Origin and how to use it in your project:
Topic | Description |
|---|---|
| XR tracking space | Describes the relationship between the XR Origin, the device tracking space and the Unity scene. |
| XR Origin configurations | Describes the different XR Origin configurations available in Unity. |
Refer to XR Origin component for more details about the XR Origin and its child GameObjects and components.
XR tracking space
XR devices choose an origin point in the real world at initialization. The positions and orientations of all tracked entities, such as the user's headset or hand-held device, XR controllers, hands, and physical objects detected around the user, are reported relative to this chosen point.
Note
The criteria for choosing the initial origin varies by platform. Typically, a device chooses a point at or directly below the user's HMD (VR) or hand-held device (AR).
If you used the tracking data directly in your scene, the user would appear to be standing at the scene origin point (0, 0 ,0). To make the user appear at a different location in the scene, you need to transform the tracking data to the desired position and orientation. Unity provides the XR Origin to do this automatically. Many Unity XR features, including those provided by AR Foundation and the XR Interaction Toolkit, require an XR Origin in the scene. You can choose from a variety of XR Origin configurations to suit your project.
To position the XR tracking space in a Unity scene, add an XR Origin GameObject at the location where you want the user to appear when the scene starts. For example, to place the user at the scene origin, place the XR Origin GameObject there. You can rotate the XR Origin around its y axis to face the user in the desired starting direction.
The XR Origin contains GameObjects representing tracked entities as children within its hierarchy. For example, the user's headset or hand-held device is represented by the Camera GameObject. Because they are children, the tracking data controlling the positions and rotations of these GameObjects is automatically transformed into world space relative to the XR Origin. When the user moves in the real world, these child GameObjects move relative to the XR Origin in the scene.
Man wearing MR headset reaches toward a virtual object
By using the XR Origin (A) as the parent for transforming tracking data, the tracking origin and the Unity scene origin (B) can be in different places and orientations.
The parent XR Origin GameObject doesn't move when the user walks around the scene. However, you can move the XR Origin with a script to allow the user to teleport or navigate around the scene via controller input.
XR Origin configurations
The Unity XR packages provide several XR Origin configurations tailored for different types of XR applications. You can use the GameObject > XR menu to add an XR Origin to the current Scene. The available options depend on which packages you have added to your project.
Important
You should never have more than one active XR Origin in a scene. If you need different configurations of the XR Origin in a scene for different purposes, only enable one at the same time.
XR type | Configuration | Menu option | Package | Notes |
|---|---|---|---|---|
| VR, MR | XR Rig | Convert Main Camera To XR Rig | XR Legacy Input Helpers (installed with the XR Plug-in Management package) | Replaces the standard Camera in a basic Unity Scene. The logic used to replace the main camera can fail in complex scenes. Unity removes this option when you install the XR Interaction Tools package. The XR Rig GameObject created by this menu option is slightly different than the XR Origin and might not be as compatible with other Unity XR features. |
| VR, MR | XR Origin | XR Origin | XR Core Utils (installed with the XR Interaction Toolkit package) | Does not include GameObjects for controllers. |
| VR, MR | XR Origin (VR) | XR Origin (VR) | XR Interaction Toolkit | Includes controller GameObjects set up for action-based input. |
| VR, MR | XR Origin (VR) | Device-based > XR Origin (VR) | XR Interaction Toolkit | Includes controller GameObjects set up for device-based input. |
| AR, MR | XR Origin (AR) | XR Origin (AR) | AR Foundation | Serves as the tracking origin for hand-held AR applications. Includes controller GameObjects. This option is available if you have the XR Interaction Toolkit installed. |
| AR | XR Origin (Mobile AR) | XR Origin (Mobile AR) | AR Foundation | Serves as the tracking origin for hand-held AR applications. Does not include controller GameObjects. This option is replaced with XR Origin (AR) if you have the XR Interaction Toolkit installed. |
Notes:
- In the latest versions of the Unity XR packages, the XR Rig has been replaced with the XR Origin.
- The component also replaces the
XROrigincomponent, providing additional settings. Refer to XR Origin component for more information.CameraOffset - The AR Session Origin configuration has been replaced with XR Origin (Mobile AR) and XR Origin (AR) in AR Foundation 5.0+.
- The XR Origin (Mobile AR) and XR Origin (AR) configurations are not compatible with earlier versions of the AR Foundation package.