Fig. 2

A diagrammatic representation of flow propagation from the seed tetrahedron to its neighboring tetrahedra through its faces. The values are given in angstroms (Å) and represent the maximum radius of the circle (MCR) that can pass through a face after considering the van der Waals radii of atoms at their vertices. If a user-defined MCR (1.4 Å) is used to scan a cavity, the algorithm A Selects a seed tetrahedron from the susceptible tetrahedra inside the cavity. B Flow transfer to three neighboring tetrahedra (T1, T2, and T3) from faces (Face 3, Face 4, and Face 2) of the seed tetrahedron, respectively. The flow is transferred across all four faces of the seed tetrahedron, as the default MCR is greater than the user-defined MCR. However, the neighboring tetrahedron of Face1 is found to be a delimiter tetrahedra; therefore, flow cannot be transferred. C Flow transfer through the eight faces of tetrahedra T1, T2, and T3, whereas one face of tetrahedron T2 is forbidden because the MCR is less than the user-defined radius