To Create a Part or Feature From Scratch (AutoCAD Mechanical Toolset)

Click Content tabLibrary panelNew Content. Find
In the New Content dialog box, select Create from scratch.
Click OK. The Content Editor opens.
Add and customize the part/feature geometry.
Note:
See the sections under Refine the Items added to a custom content library for related instructions.
Click Content Editor tabContent Views panel.Save Find
The Save Content As dialog box displays.
In the Content panel of the Save Content As dialog box, select the folder you want to add the item to.
In the Save as section, specify a name for the new item.
In the View section, from the View list, select the name of the orthogonal view you are adding.
If the drawing you are adding is a sectional view, from the Type list select the type of sectional view.
If you are not creating a sectional view, select None.
Click Save Content.