In Toolspace, on the Prospector tab, expand the surface Definition collection, right-click , and click Add.
In the Add Breaklines dialog box, enter the breakline description in the Description field.
Select Proximity from the Type list.
Optionally, if the object from which you are creating a breakline has curves, enter a value into the Mid-Ordinate Distance field or click to digitize a distance in the drawing area.
The Add Breaklines dialog box is closed. You are prompted to select an object.
Select one or several objects to define the breakline.
This creates breaklines and adds them to the surface Breaklines collection in the Prospector tree.