@rhino16 @paul.metzger
New Version, it works on example given, sometimes it outputs more geometry than number of roof but this is due to bad roof border. I mean very sharp angles that generates intersection at places not intended.
Implementation is surely not bullet proof. I first take all roofs touching the ground then I union all parts. Then search for holes. Then put in holes geometries that were not used and not having a bounding box center coincident with a previous geometry.
I also change the way curve is transformed to Polyline. So if it already a Polyline, there will be no changes.
sand_dune_internal_curves_csharp_RH7_LEGACY.gh (103.2 KB)