With the structure catalog, you manage definitions of mechanical structure components and folders.
The current tab contains the definitions of components and folders in the current drawing. You can create a new instance of a component or folder by dragging the definition of a component view or folder from the structure catalog on to model space.
You can also drag component views and folders from any mechanical structure-enabled source drawings to your current drawing and create external (xref) reference components and folders. Press the CTRL key while dragging, the components and folders are copied instead of being inserted as xref entities. Source drawings can be on your computer, on a network location or in Autodesk Vault.
After you insert a component view by dragging a component view on to model space, you must follow the procedure for inserting views to an existing instance of a component to insert the remaining views of the component.