Use cloud anchors to create multiplayer or collaborative AR experiences that Android and iOS users can share.
How cloud anchors work
Cloud anchors let you make ARKit and/or ARCore anchors available to multiple devices in the same environment.
Users in the same environment can add cloud anchors to the AR scene that they see on their device.
Your app can render 3D objects attached to the cloud anchors, letting users see and interact with the objects simultaneously.
To make these shared AR experiences possible, the ARCore SDK uses Google servers to host and resolve anchors.
Hosting an anchor maps it in a common coordinate system for a given physical space.
When you host an anchor, ARCore sends relevant visual mapping data from a user's environment to Google servers. Once this data is uploaded, it is processed into a sparse point map, similar to an ARCore point cloud.
Resolving cloud anchors lets multiple devices in a given physical space add previously hosted anchors to their scene.
A cloud anchor resolve request sends visual feature descriptors from the current frame to the server. The server attempts to match the visual features to the sparse point map. This lets your app situate resolved anchors consistently in the scene that each user sees on their device.
Data storage and access limitations
Cloud anchors have the following data storage and access limitations:
Cloud anchors can be resolved for twenty-four hours after they are hosted.
Raw visual mapping data uploaded to the cloud when hosting an anchor is discarded after seven days.
Anchors are resolved on the server side against the stored sparse point map.
- The sparse point map can be used for cloud anchor resolution requests for twenty-four hours after it is generated.
- Previously uploaded mapping data is never sent to a user's device.
It is not possible to determine a user's geographic location or to reconstruct any images or the user's physical environment from the sparse point map.
Visual feature descriptors from a request to resolve an anchor are never stored.
To start using cloud anchors, see the Cloud Anchors Quickstart.
If you are new to working with anchors, see Working with Anchors for an introduction.