Hi,
if I understand your question correct you could e.g. use the "waterdrop"-function, that will run along the base between two hills.
The other option would be to create watersheds. Look >>>here<<< for details.
HTH, - alfred -
That's kind of a Catch 22 situation. [IOW you can't find B without knowing A and you can't know A without finding B]. Any breakline you draw based only on the information extracted from the surface will not affect the surface. If the only source for elevations you have is the contours. The only way to get elevations for a breakline is to extract them from the surface. So the breakline will not affect the surface any.
You need an external source for the position and elevation of the bottom of the hill. You might be able to get the location from an aerial if the hill were well defined enough. But you'd still have the same situation for the elevations.
Allen
Allen Jessup
Engineering Specialist / CAD Manager