The first is referred to as structure-based drug design (also known as direct drug design) and relies on knowledge of the three dimensional structure of the biological target obtained through methods such as x-ray crystallography or NMR spectroscopy.
The first is referred to as structure-based drug design and the second, ligand-based drug design (or indirect drug design). Structure-based drug design relies on knowledge of the three dimensional structure of the biological target obtained through methods such as x-ray crystallography or NMR spectroscopy.