Push/Pull Tool – Sub Face Mode – I find that I often use this tool to stretch, change, or edit 3D objects. As the name suggests this tool is used to push or pull 3D objects. This tool can be used to add or subtract solids, and you can use it to edit only a portion of the object.
The third mode requires an additional part, a planar object. This object is then used to add, subtract, or edit the base object.