Getting perimeter of all elements in different heights

Hello everybody,
I try to create an “overview map” from a construction site. My idea is to create the outlines of every element in the model, so that in the end I have a top view plan, but with different heights.

For some elements I got a result, shown in the pictures. But with all elements, dynamo and revit chrash.

Is there a way or does anyone have an idea, how to manage the whole data?
Or is there a more efficient way to achieve the goal?

In the end, I want to invastigate, if a path finding method through the construction site is possible.