One such approach is ligand-based drug design (LBDD), which relies on the analysis of known active compounds rather than the target protein itself. LBDD typically involves comparing the chemical features of known actives to those of putative inactives in order to identify pharmacophores -sets of chemical properties necessary for activity against a target . These pharmacophores can be one, two, or three-dimensional, providing an understanding of active molecule properties or shape . The generated pharmacophores are used to screen large libraries of compounds to find drug-like molecules with similar properties. LBDD allows for fast screening of incredibly large molecule libraries. Still, its reliance on empirical observations means it can struggle to capture subtle differences between closely related analogs. The results may not always generalize to a new series of compounds.