For a scene, identification parameters specify a kind of container called an anchor. In effect, an anchor is the object that defines all identification parameters.
By default, a scene has one anchor, called the SceneAnchor, which specifies the identification parameters that are used to locate the scene. In addition, other anchors can be added and/or modified for use in different situations. When there are multiple anchors for a scene, you define the relative relationship between them, as described in Anchor Relationships.
Anchors are listed in the Toolbox.
