Model-Based Definition > Geometric Dimensioning and Tolerancing Advisor > Advisor Message Help > Datum Messages > User-Defined Datum Requires Targets
  
User-Defined Datum Requires Targets
For a user-defined datum, you must define the datum targets in the CAD model and then add the datum target symbols. For more information, see User-Defined Datums in Model Based Design > Geometric Dimensioning and Tolerancing Advisor > GD&T Advisor.