where IGM,inter free inter free ( ) ( ) (5) with A and i being the index of fragments and atoms, respectively. Two or more fragments can be defined based on actual needs. IGM employs sign(2) to color 𝛿𝑔 or 𝛿𝑔 inter or 𝛿𝑔 intra isosurfaces to distinguish the interaction strengths and types, which is in analogy with NCI and IRI.