Use the Add Breaklines dialog box to create a non-destructive breakline from either a grading feature line or an open or closed AutoCAD object.
When defining a non-destructive breakline, surface points are created at each vertex of the object and at each intersection of a surface triangle edge and the non-destructive breakline object. The new points create additional surface triangles. Non-destructive breaklines are often needed when deleting surface areas where a clean TIN edge does not exist.
The elevation for each new point is extracted from the original surface triangle, therefore maintaining the integrity of the original surface.