Road to Topography Struggle

Hi, I’ve been making subregions and pasting their shapes to make floors to bring to the elevations of the topography in dynamo. For some reason this does not work with this shape and I don’t understand why. Any suggestions? (also it is close to the building pad but not touching it.

Thanks for any help!

This is almost impossible to confirm without having access to the actual revit files, but perhaps it is due to the road not falling completely within the confines of the topography?

@jmccleskey have a look at this recent thread, is this more or less what you are going for?: