Fundamentals > Creo Parametric User Interface > The Analysis Tab > Measuring Geometry > Measuring Entities > Using Specific Measurement Types > Distance > Using Reference Entity Options > Example: Plane Option
  
Example: Plane Option
The Plane Option Is Not Selected for the Surface
The distance is measured from the actual surface to the second selected entity.
The Plane Option Is Selected for the Surface
The distance is measured from the plane that would be formed by extending the surface to the second selected entity in the normal direction.