Can I calculate the approximate average slope of a (non-planar) shape?

Note:
CGA stands for Computer Generated Architecture, a scripting language specific to Esri CityEngine and used to generate 3D content. See the link to the 'Basics of Rule-based Modeling' in the Related Information section below.

Code:
slopeFunction = atan ( sqrt ( scope.sy / scope.sz) )

Lot -->
    alignScopeToAxes(y)
    print ( slopeFunction )