If you want to get the start and end points of the bottom of MEP Pipe system families in Revit simply add the nodes shown in the image below.
Why do you need this information you may ask? First of all, Revit does not easily display the start and end points at the bottom of a pipe families. So, use this information as you wish or tell a Revit Friend. I am sure someone you know will want to use it. Good Luck!