When more than two patches overlap each other from the top view, but do not intersect completely in 3D, finding a solution is increasingly complex as shown in figure 13.
Figure 13: Plan view of three intersecting gradings
If you look closely from the side, you can see that two of the patches do not intersect at all, and the other intersections are incomplete.
Figure 14: Side views of three intersecting gradings
In this case, Autodesk Civil 3D can resolve the conflict through a process of elevation averaging, but as the ambiguous region becomes more complex, the resolution is more difficult. Figure 15 shows the cleaned-up 3D view of the three intersecting gradings.
Figure 15: Calculated transition for three intersecting gradings