> [!WARNING]
> **Preview:** Currently, spatial anchoring is only available in [Full Space](https://developer.android.com/design/ui/xr/guides/foundations#modes).

An anchor is a locked virtual point to a physical object. Spatial anchors can
be presented to users as visual markers.

You can use anchors across a wide range of use cases to represent points derived
from your app's content, AI-generated markers, or even user-generated points.
Anchors are most useful for pinned objects, like a point of interest or
identifying an object for the user.

## User comfort

Unlike other spatial UI that will move with the user's head movement, anchors
remain locked to a specific spot, even when the user moves around.

When using spatial anchors, consider how they will interact with the rest of
your user's spatial environment. Try to avoid sizing and orientation that will
make the user back up or be unsure of anchor placement.

## Markers

Markers are UI affordances attached to the objects in the user's field of
vision. A spatial marker has multiple forms, including dot, icon, or
drawing.
![A user looking at an XR app, with a natural eye level that's 5 degrees below the panel center.](https://developer.android.com/static/images/design/ui/glasses/guides/spatial_anchor_marker_distance.webp) Markers assisting with shopping.

### Icon markers

An icon marker is a small dot like UI element that marks objects of interest in
the user's environment. Read more on [icon markers](https://developer.android.com/design/ui/ai-glasses/guides/components/icon-marker).
Alas, your browser doesn't support HTML5 video. That's OK! You can still [download the video](https://developer.android.com/static/videos/design/ui/xr/anchor_tracking.mp4) and watch it with a video player. A marker and card can help identify a QR.

### Glimmer UI

Markers can be tied to other UI, like Jetpack Compose Glimmer
components.

![Example of glimmer UI attached to an icon marker](https://developer.android.com/static/images/design/ui/xr/guides/spatial_anchor_marker_icon.webp)

### Drawing

Drawing markers are drawn at runtime and glimmer themed to provide greater
visual help than a dot or frame can provide. For example, a directional is
present on display to show the user where to look or navigate.

![Arrow drawing pointing out a landmark](https://developer.android.com/static/images/design/ui/xr/guides/spatial_anchor_marker_drawing.webp)

## Behaviors

Markers, and any attached UI, should behave as spatial UI, meaning the actual
distance of the marked object should be reflected in the size of the UI, using
a constant angular DP size.

Elements can also respond to the user's movement, either rotating towards them
while being affected by gravity or only partial rotation.

### Clustering

Clearly define markers to avoid visual clutter, and limit the
number of markers within view. If multiple markers are needed,
cluster them together as one, more-prominent marker that can be progressively
viewed.

### Anchor target

Markers have an average angular target angular target size of 7°.

The hand-based raycasting cursor will only show near an active target. If the
target is small, then the user can struggle to get their hand in the right
orientation to have the cursor show up at all. In this case a cursor catcher
can be used to help targeting. A cursor catcher is a blank target behind smaller
targets that will show the cursor and aid targeting small targets.