Spherical map using TIP3P model Directional grid maps calculated with OW and HW probes from the TIP3P model were combined to derive a non-directional interaction grid map, which was tested for the placement of spherical water molecules. To calculate the values for this map, at each grid point the predefined set of 9897 orientations was placed and their energy interpolated from the OW and HW grid maps. Then, the energy E n of a water molecule n at a given position in the grid was calculated as the Boltzmann-weighted average energy of the orientation ensemble (eq. 3):