Neutral or cut line line between two Dtm surfaces

An alternative method to get the neutral position using the zero contour.

The cut line can accurately be defined by doing the following:

Use the Terrace - Cut & fill procedure and do a volume calculation between the 2 projects.
On the output page save the depth points to an empty project.

After the cut and fill is done, activate the new project, search for triangles and copy the zero contour to cad.

That contour line is also the neutral position.

See video :  Cut Line.