Applicable XR devices This guidance helps you build experiences for these types of XR devices. [Learn about XR device types →](https://developer.android.com/develop/xr/devices.md.txt)  XR Headsets [](https://developer.android.com/develop/xr/devices.md.txt#xr-headsets)  Wired XR Glasses [](https://developer.android.com/develop/xr/devices.md.txt#xr-glasses) [Learn about XR device types →](https://developer.android.com/develop/xr/devices.md.txt)
After the user [grants permission for face tracking](https://developer.android.com/training/permissions/requesting.md.txt),
your app can retrieve face shape information through ARCore for Jetpack XR. Face
shape information can help your app display the user in the virtual world, for
example, for a virtual glasses try-on.
## Create an ARCore for Jetpack XR session
Obtain face information through a Jetpack XR Runtime [`Session`](https://developer.android.com/reference/kotlin/androidx/xr/runtime/Session.md.txt),
which your [app can create](https://developer.android.com/develop/xr/jetpack-xr-sdk/add-session.md.txt#access-session).
## Configure the session
Face tracking is not enabled by default on XR sessions. To enable face tracking,
configure the session and set the
[`FaceTrackingMode.USER`](https://developer.android.com/reference/kotlin/androidx/xr/runtime/FaceTrackingMode.md.txt#USER()) mode:
```kotlin
val newConfig = Config.Builder(session.config)
.setFaceTracking(FaceTrackingMode.BLEND_SHAPES)
.build()
when (val result = session.configure(newConfig)) {
is SessionConfigureSuccess -> TODO(/* Success! */)
else ->
TODO(/* The session could not be configured. See SessionConfigureResult for possible causes. */)
}
```
> [!NOTE]
> **Note:** Enabling this mode requires the `android.permission.FACE_TRACKING` [runtime permission](https://developer.android.com/training/permissions/requesting.md.txt) to be granted to your app.
## Retrieve face data
Use [`Face.getUserFace(session)`](https://developer.android.com/reference/kotlin/androidx/xr/arcore/Face.md.txt#getUserFace(androidx.xr.runtime.Session)) to retrieve user face data, which
contains the following:
- **Face blendshape values** : A face's possible expressions are a combination of [68 blend shape values](https://developer.android.com/reference/kotlin/androidx/xr/arcore/FaceBlendShapeType.md.txt). Each blend shape value represents a facial movement or deformation of the face, and the value indicates its intensity, ranging from `0.0` to `1.0`. For an explanation of each blend shape type, see [Understand face blendshape types](https://developer.android.com/develop/xr/jetpack-xr-sdk/arcore/face.md.txt#blendshape-table).
- **Confidence values for regions** : The face has [three regions](https://developer.android.com/reference/kotlin/androidx/xr/arcore/FaceConfidenceRegion.md.txt). Confidence values indicate the degree of certainty of accuracy for the given poses, ranging from `0.0` to `1.0`, where `1.0` indicates the highest confidence.
```kotlin
val face = Face.getUserFace(session)
face.state.collect { state ->
if (state.trackingState != TrackingState.TRACKING) return@collect
val confidence = state.getConfidence(FaceConfidenceRegion.LOWER)
val blendShapeValue = state.blendShapes[FaceBlendShapeType.LIPS_TOWARD]
}
```
## Understand face blendshape types
The following tables list each [type of face blend shape](https://developer.android.com/reference/kotlin/androidx/xr/arcore/FaceBlendShapeType.md.txt):
### Upper region blendshapes
| Name | Reference Images ||
|---|---|---|
| `BROW_LOWERER_L` |  `BROW_LOWERER_L = 0.0` |  `BROW_LOWERER_L = 1.0` |
| `BROW_LOWERER_R` |  `BROW_LOWERER_R = 0.0` |  `BROW_LOWERER_R = 1.0` |
| `EYES_CLOSED_L` |  `EYES_CLOSED_L = 0.0` |  `EYES_CLOSED_L = 1.0` |
| `EYES_CLOSED_R` |  `EYES_CLOSED_R = 0.0` |  `EYES_CLOSED_R = 1.0` |
| `EYES_LOOK_DOWN_L` |  `EYES_LOOK_DOWN_L = 0.0` |  `EYES_LOOK_DOWN_L = 1.0` |
| `EYES_LOOK_DOWN_R` |  `EYES_LOOK_DOWN_R = 0.0` |  `EYES_LOOK_DOWN_R = 1.0` |
| `EYES_LOOK_LEFT_L` |  `EYES_LOOK_LEFT_L = 0.0` |  `EYES_LOOK_LEFT_L = 1.0` |
| `EYES_LOOK_LEFT_R` |  `EYES_LOOK_LEFT_R = 0.0` |  `EYES_LOOK_LEFT_R = 1.0` |
| `EYES_LOOK_RIGHT_L` |  `EYES_LOOK_RIGHT_L = 0.0` |  `EYES_LOOK_RIGHT_L = 1.0` |
| `EYES_LOOK_RIGHT_R` |  `EYES_LOOK_RIGHT_R = 0.0` |  `EYES_LOOK_RIGHT_R = 1.0` |
| `EYES_LOOK_UP_L` |  `EYES_LOOK_UP_L = 0.0` |  `EYES_LOOK_UP_L = 1.0` |
| `EYES_LOOK_UP_R` |  `EYES_LOOK_UP_R = 0.0` |  `EYES_LOOK_UP_R = 1.0` |
| `INNER_BROW_RAISER_L` |  `INNER_BROW_RAISER_L = 0.0` |  `INNER_BROW_RAISER_L = 1.0` |
| `INNER_BROW_RAISER_R` |  `INNER_BROW_RAISER_R = 0.0` |  `INNER_BROW_RAISER_R = 1.0` |
| `LID_TIGHTENER_L` |  `LID_TIGHTENER_L = 0.0` |  `LID_TIGHTENER_L = 1.0` |
| `LID_TIGHTENER_R` |  `LID_TIGHTENER_R = 0.0` |  `LID_TIGHTENER_R = 1.0` |
| `OUTER_BROW_RAISER_L` |  `OUTER_BROW_RAISER_L = 0.0` |  `OUTER_BROW_RAISER_L = 1.0` |
| `OUTER_BROW_RAISER_R` |  `OUTER_BROW_RAISER_R = 0.0` |  `OUTER_BROW_RAISER_R = 1.0` |
| `UPPER_LID_RAISER_L` |  `UPPER_LID_RAISER_L = 0.0` |  `UPPER_LID_RAISER_L = 1.0` |
| `UPPER_LID_RAISER_R` |  `UPPER_LID_RAISER_R = 0.0` |  `UPPER_LID_RAISER_R = 1.0` |
### Lower region blendshapes
| Name | Reference Images ||
|---|---|---|
| `CHEEK_PUFF_L` |  `CHEEK_PUFF_L = 0.0` |  `CHEEK_PUFF_L = 1.0` |
| `CHEEK_PUFF_R` |  `CHEEK_PUFF_R = 0.0` |  `CHEEK_PUFF_R = 1.0` |
| `CHEEK_RAISER_L` |  `CHEEK_RAISER_L = 0.0` |  `CHEEK_RAISER_L = 1.0` |
| `CHEEK_RAISER_R` |  `CHEEK_RAISER_R = 0.0` |  `CHEEK_RAISER_R = 1.0` |
| `CHEEK_SUCK_L` |  `CHEEK_SUCK_L = 0.0` |  `CHEEK_SUCK_L = 1.0` |
| `CHEEK_SUCK_R` |  `CHEEK_SUCK_R = 0.0` |  `CHEEK_SUCK_R = 1.0` |
| `CHIN_RAISER_B` |  `CHIN_RAISER_B = 0.0` |  `CHIN_RAISER_B = 1.0` |
| `CHIN_RAISER_T` |  `CHIN_RAISER_T = 0.0` |  `CHIN_RAISER_T = 1.0` |
| `DIMPLER_L` |  `DIMPLER_L = 0.0` |  `DIMPLER_L = 1.0` |
| `DIMPLER_R` |  `DIMPLER_R = 0.0` |  `DIMPLER_R = 1.0` |
| `JAW_DROP` |  `JAW_DROP = 0.0` |  `JAW_DROP = 1.0` |
| `JAW_SIDEWAYS_LEFT` |  `JAW_SIDEWAYS_LEFT = 0.0` |  `JAW_SIDEWAYS_LEFT = 1.0` |
| `JAW_SIDEWAYS_RIGHT` |  `JAW_SIDEWAYS_RIGHT = 0.0` |  `JAW_SIDEWAYS_RIGHT = 1.0` |
| `JAW_THRUST` |  `JAW_THRUST = 0.0` |  `JAW_THRUST = 1.0` |
| `LIP_CORNER_DEPRESSOR_L` |  `LIP_CORNER_DEPRESSOR_L = 0.0` |  `LIP_CORNER_DEPRESSOR_L = 1.0` |
| `LIP_CORNER_DEPRESSOR_R` |  `LIP_CORNER_DEPRESSOR_R = 0.0` |  `LIP_CORNER_DEPRESSOR_R = 1.0` |
| `LIP_CORNER_PULLER_L` |  `LIP_CORNER_PULLER_L = 0.0` |  `LIP_CORNER_PULLER_L = 1.0` |
| `LIP_CORNER_PULLER_R` |  `LIP_CORNER_PULLER_R = 0.0` |  `LIP_CORNER_PULLER_R = 1.0` |
| `LIP_FUNNELER_LB` |  `LIP_FUNNELER_LB = 0.0` |  `LIP_FUNNELER_LB = 1.0` |
| `LIP_FUNNELER_LT` |  `LIP_FUNNELER_LT = 0.0` |  `LIP_FUNNELER_LT = 1.0` |
| `LIP_FUNNELER_RB` |  `LIP_FUNNELER_RB = 0.0` |  `LIP_FUNNELER_RB = 1.0` |
| `LIP_FUNNELER_RT` |  `LIP_FUNNELER_RT = 0.0` |  `LIP_FUNNELER_RT = 1.0` |
| `LIP_PRESSOR_L` |  `LIP_PRESSOR_L = 0.0` |  `LIP_PRESSOR_L = 1.0` |
| `LIP_PRESSOR_R` |  `LIP_PRESSOR_R = 0.0` |  `LIP_PRESSOR_R = 1.0` |
| `LIP_PUCKER_L` |  `LIP_PUCKER_L = 0.0` |  `LIP_PUCKER_L = 1.0` |
| `LIP_PUCKER_R` |  `LIP_PUCKER_R = 0.0` |  `LIP_PUCKER_R = 1.0` |
| `LIP_STRETCHER_L` |  `LIP_STRETCHER_L = 0.0` |  `LIP_STRETCHER_L = 1.0` |
| `LIP_STRETCHER_R` |  `LIP_STRETCHER_R = 0.0` |  `LIP_STRETCHER_R = 1.0` |
| `LIP_SUCK_LB` |  `LIP_SUCK_LB = 0.0` |  `LIP_SUCK_LB = 1.0` |
| `LIP_SUCK_LT` |  `LIP_SUCK_LT = 0.0` |  `LIP_SUCK_LT = 1.0` |
| `LIP_SUCK_RB` |  `LIP_SUCK_RB = 0.0` |  `LIP_SUCK_RB = 1.0` |
| `LIP_SUCK_RT` |  `LIP_SUCK_RT = 0.0` |  `LIP_SUCK_RT = 1.0` |
| `LIP_TIGHTENER_L` |  `LIP_TIGHTENER_L = 0.0` |  `LIP_TIGHTENER_L = 1.0` |
| `LIP_TIGHTENER_R` |  `LIP_TIGHTENER_R = 0.0` |  `LIP_TIGHTENER_R = 1.0` |
| `LIPS_TOWARD` |  `LIPS_TOWARD = 0.0` |  `JAW_DROP = 1.0 and LIPS_TOWARD = 1.0` |
| `LOWER_LIP_DEPRESSOR_L` |  `LOWER_LIP_DEPRESSOR_L = 0.0` |  `LOWER_LIP_DEPRESSOR_L = 1.0` |
| `LOWER_LIP_DEPRESSOR_R` |  `LOWER_LIP_DEPRESSOR_R = 0.0` |  `LOWER_LIP_DEPRESSOR_R = 1.0` |
| `MOUTH_LEFT` |  `MOUTH_LEFT = 0.0` |  `MOUTH_LEFT = 1.0` |
| `MOUTH_RIGHT` |  `MOUTH_RIGHT = 0.0` |  `MOUTH_RIGHT = 1.0` |
| `NOSE_WRINKLER_L` |  `NOSE_WRINKLER_L = 0.0` |  `NOSE_WRINKLER_L = 1.0` |
| `NOSE_WRINKLER_R` |  `NOSE_WRINKLER_R = 0.0` |  `NOSE_WRINKLER_R = 1.0` |
| `UPPER_LIP_RAISER_L` |  `UPPER_LIP_RAISER_L = 0.0` |  `UPPER_LIP_RAISER_L = 1.0` |
| `UPPER_LIP_RAISER_R` |  `UPPER_LIP_RAISER_R = 0.0` |  `UPPER_LIP_RAISER_R = 1.0` |
| `TONGUE_OUT` |  TONGUE_OUT = 0.0 |  TONGUE_OUT = 1.0 |
| `TONGUE_LEFT` |  TONGUE_LEFT = 0.0 |  TONGUE_LEFT = 1.0 |
| `TONGUE_RIGHT` |  TONGUE_RIGHT = 0.0 |  TONGUE_RIGHT = 1.0 |
| `TONGUE_UP` |  TONGUE_UP = 0.0 |  TONGUE_UP = 1.0 |
| `TONGUE_DOWN` |  TONGUE_DOWN = 0.0 |  TONGUE_DOWN = 1.0 |