Find element indices (zero based9 of the elements being the upper-most element in its column.

Each column is identified by matching node id numbers. For 3D elements the last half of the node numbers of the bottom element must match the first half of the node numbers in the top element. For 2D vertical elements the order of the node numbers in the bottom element (last half number of nodes) are reversed compared to those in the top element (first half number of nodes).

Find element indices (zero-based) of the elements being the upper-most element in its column.

Each column is identified by matching node id numbers. For 3D elements the last half of the node numbers of the bottom element must match the first half of the node numbers in the top element. For 2D vertical elements the order of the node numbers in the bottom element (last half number of nodes) are reversed compared to those in the top element (first half number of nodes).

Find element indices (zero based) of the elements being the upper-most element in its column.

This method uses the element center (x,y) coordinate, and identifies each column by having the same element center (x,y) coordinate.