Elevation surfaces -- Cutting planes

[Mohamad jadi <mohamad@xxxxxxxx>]

Ugo (and others), have you thought about how to "cut" the elevation surfaces?  
Thinking parametrically, perhaps a function like: ((x, y)-->z)
-->((x, y) -->z)?  Cutting planes could be parameters too.  Just rambling...

-- mohamad
LANL