The Attachment node is used to define a set of edges on a flexible shell which can be used to connect it with other components through a joint in the Multibody Dynamics interface. All the selected edges behave as if they were connected by a common rigid body.
The Attachment node is available with the addition of the Multibody Dynamics Module. The use of attachments is discussed in the Attachments section in the Multibody Dynamics Module User’s Guide.