I am working on a project in which we are building a campus on a parking lot.
I want to create a site model which will sit on the model of the parking lot. The ceiling of the parking lot is complicated and has several inclines and different heights.
I thought about a couple options how to do it, but none of them seems to work properly.
Create a site model as existing with the heights of the parking lot ceiling and then add the contours of the final topography as proposed contour
Hopefully this helps more than a simple verbal description...
I did a quick mockup to test the process in VW and to try out the terrain sculpting tool for the first time :) Wow, that is a cool tool. Keep in mind, I am just learning VW, so there may be faster, easier, or automated ways to do this. This is just what I know how to do from many years of AutoCAD.
1 - Here's a roof deck I imagined based on your description. Note the different slopes, elevations, and parapet wall.