Encapsulate

Encapsulates a portion of the scene by collapsing the hierarchy and replacing it with a procedural which will be evaluated at render time.

This has two primary uses :

To optimise scene generation. Downstream nodes do not see the encapsulated locations, so do not spend time processing them.
To enable high-level instancing of hierarchies. If multiple copies of the encapsulated procedural are made by the downstream network, then the procedural itself can be instanced at render time. This works no matter how the copies are made, but typically the Instancer or Duplicate nodes would be the most common method of copying the procedural.

Note

Encapsulation currently has some limitations

Motion blur options are taken from the globals at the point of Encapsulation, not the downstream globals at the point of rendering.
Motion blur attributes are not inherited - only attributes within the encapsulate hierarchy are considered.

user

Container for user-defined plugs. Nodes should never make their own plugs here, so users are free to do as they wish.

The processed output scene.

The on/off state of the node. When it is off, the node outputs the input scene unchanged.

The input scene

The filter used to control which parts of the scene are processed. A Filter node should be connected here.