I have been working on another maxscript to add to those I released a few months back. This one is particularly useful for improving the triangulation on your mesh terrain. It basically retriangulates the verts on each selected face so they have a diagonal to the selected key vertices. You can edit many faces at once and set ignore verts too which you don’t want their diagonals editing. Useful for odd corners.
Anyway here are some screenshots to demonstrate the process, and also a download link.