Part Modeling > Datum Features > Datum Points > General Datum Points > About Datum Points On or Offset from a Surface
  
About Datum Points On or Offset from a Surface
To place a point on a surface or quilt, you must dimension the point to two references. These dimensions are considered offset reference dimensions. Each new point placed on a surface or quilt has a placement handle displayed at the selection location, and two offset reference handles that you use to dimension the point to the model geometry. Initially, the offset reference handles are not attached to any reference.