The dipolar interaction yields the most direct information with respect to structure as it makes it possible to measure the distances between the spins.  The sensitivity of this interaction is however lacking and even though dipolar-based NMR crystallography makes the elucidation of structures possible, other methods are necessary to obtain high resolution structures.  For these reasons much work was done to include the use other NMR observables such as chemical shift anisotropy, J-coupling and the quadrupolar interaction.  These anisotropic interactions are highly sensitive to the 3D local environment making it possible to refine the structures of powdered samples to structures rivaling the quality of single crystal X-ray diffraction.  These however rely on adequate methods for predicting these interactions as they do not depend in a straightforward fashion on the structure.