Methods to define element sizes

The easiest meshing is defining a global size and small elements for features are automatically calculated.
User can define a chordal error (geometry - mesh error)
User can manually define sizes over geometrical entities. This sizes can be automatically corrected to allow meshing checking Preferences->Meshing->General: Automatic correct sizes.
The transition between sizes is controlled by a factor that the user can define (Preferences->Meshing->General: Size transitions).