user has a large site plan. picture rolling hills and many houses. in SU, user has established these rolling hills, built his buildings, and so on.

meanwhile, in AutoCAD, everything is a 2-D world. but this is where the user is designing the landscape design.

we have a AutoLISP routine that creates a text file for SU, with a list of components to represent each tree and shrub, and an X,Y coordinate for where they need to go.

So I have a Ruby script that reads in that text file, loads each component, and places it at that X,Y coordinate.

yet, they are all at Z level 0. I would like to have them all at the appropriate Z elevation, to match the rolling hills that the user has.

This is for hundreds, if not thousands of components. there is to be no user interaction other than initially firing this Ruby script. It is to read in the components to place, and then place them at the correct locations.

So, again, given an X,Y coordinate, how do I determine the appropriate Z elevation to snap to a SU contour?

--J