For each slice, we only keep a subset of MO amplitude data points by filtering out any point that lies more than x Å away from (0, 0). In most cases, reasonable choices of x lie between 0.5 Å to 1.0 Å. After filtering, we locate all the places where the MO amplitude changes sign, i.e., we find the ⇡-nodal plane. This gives two lists of points: one with points found before reaching zero (list A) and one with points found after a zero (list B). A new set of points is calculated (list C) as the midpoint between the corresponding points in A and B.