You can edit Elements by swapping their diagonal.
You may need to do this to ensure that the model accurately reflects the surface following:
•Triangulation; or a
To Swap Element Diagonals:
•Activate the DTM View.
oClick Surface > Elements > Swap Diagonal; or
oClick the Swap Element Diagonal Tool-button on the Element Toolbar.
•Click on the DTM View close to the diagonal that you want to swap.