INTERFACE Curvature2D;

IMPORT Energy;

TYPE
  T <: Public;
  Public = Energy.T OBJECT METHODS
      init(): T;
    END;
  (*
    The "Curvature 2D" energy measures the outer dihedral angles between 
    adjacent faces.
    
    This energy is computed only for faces that:

    - exist,
    - belong to the same original face, and
    - are adjacent to one common edge.
    
    The energy depends on the actual angle "A", as
    "1 + cos(A); which reaches its minimum when "A=Pi".
  *)

END Curvature2D.