Surface Tracking allows to detect horizontal and vertical planes in your environment.
When creating a Surface scene in Studio, a 25x25cm placeholder will appear on the grid. You can take this size as a reference for displaying your elements at real-world scale.
When running a Surface scene you will be asked to move your device around in order to detect planes in your environment. Once a plane is detected you will be able to place your virtual objects and merge them with the real world.
When running Surface experiences in devices non-compatible with ARCore or ARKit, surface detection will be emulated with device's motion sensors.