A content library is a collection of pre-drawn parts and features that you can insert into drawings.
The AMCONTENTLIB command gives you the ability to browse or search the content libraries to locate the right part or feature. Thereafter, it displays a wizard to assist you pick the size and the view to place in the drawing. If you require to draw the other views of this part or feature, you can use the AMPOWERVIEW command to generate them.
AutoCAD Mechanical toolset ships with content libraries that contain over a half a million pre-drawn standard parts and features. They comply with a wide range of international drafting standards. Autodesk periodically updates content libraries and makes them available through Autodesk 360. You can sign in to Autodesk 360, check for updates, and update your content libraries, if new updates exist.
You can customize the standard part libraries, create your own content libraries from scratch, or use content libraries created by others.
Content libraries can save you much time and effort by providing access to a wide range of pre-drawn content, which you can for reuse and share.