Class ARSessionOrigin
An ARSessionOrigin is the parent for an AR setup. It contains a Camera and
any GameObjects created from detected features, such as planes or point clouds.
Inherited Members
Namespace: UnityEngine.XR.ARFoundation
Assembly: Unity.XR.ARFoundation.dll
Syntax
[DisallowMultipleComponent]
[Obsolete("ARSessionOrigin has been deprecated. Use XROrigin instead.")]
public class ARSessionOrigin : XROriginRemarks
Session space vs. Unity space
Because an AR device will be used to drive the Camera's position and rotation,
you cannot directly place the Camera at an arbitrary position in the Unity scene.
Instead, you should position the ARSessionOrigin. This makes the Camera
(and any detected features) relative to that as a result.
It is important to keep the Camera and detected features in the same space relative to
each other (otherwise, detected features like planes won't appear in the correct place relative
to the Camera). The space relative to the AR device's starting position is called
"session space" or "device space". For example, when the AR session begins, the device might
report its position as (0, 0, 0). Detected features, such as planes, will be reported relative
to this starting position. The purpose of the ARSessionOrigin is to convert the session space
to Unity world space.
To facilitate this, the ARSessionOrigin creates a new GameObject called "Trackables"
as a sibling of its Camera. This should be the parent GameObject for all
detected features.
At runtime, a typical scene graph might look like this:
- AR Session Origin
- Camera
- Trackables
- Detected plane 1
- Detected plane 2
- Point cloud
- etc...
You can access the "trackables" GameObject with trackablesParent.
Note that the localPosition and localRotation of detected trackables
remain in real-world meters relative to the AR device's starting position and rotation.
Scale
If you want to scale the content rendered by the ARSessionOrigin you should apply
the scale to the ARSessionOrigin's transform. This is preferrable to scaling
the content directly, which can have undesirable side effects. Physics and NavMeshes,
for example, do not perform well when scaled very small.
Properties
camera
(Deprecated) The Camera to associate with the AR device. It must be a child of this ARSessionOrigin.
Declaration
[Obsolete("camera has been deprecated. Use Camera instead.")]
public Camera camera { get; set; }Property Value
| Type | Description |
|---|---|
| Camera |
trackablesParent
(Deprecated) The parent Transform for all "trackables" (for example, planes and feature points).
Declaration
[Obsolete("trackablesParent has been deprecated. Use TrackablesParent instead.")]
public Transform trackablesParent { get; }Property Value
| Type | Description |
|---|---|
| Transform |