Important Update:  The workflow for creating an evaluator that calculates the surface area at each floor level needed to be updated to work with the latest release of Dynamo. The original method demonstrated in the video -- creating a series of XY planes that can be intersected with the tower form -- no longer works properly. It now returns only the portion of the intersection in the first quadrant (where X and Y are greater than 0), so you cannot use this intersection to compute the area of each floor, because the curves are incomplete.The example files now illustrate a revised approach that creates a rectangle object at the origin as a substitute for the XY plane, then uses these translated rectangles to intersect with the building form. The intersection of these rectangles with the building form returns the full path of the intersection, and this allows the logic of using these closed paths to create surfaces and report the areas works properly in this approach.
So, be sure to download the latest files for this example from our shared Google Drive using the link above.