Existing Contours to Polysurface


I am having issues creating an accurate surface of existing topography lines, specifically when contours follow the building footprint. It creates undesirable surfaces. I want it to be a flat surface while smooth out at the contours.

Additionally, I have occasional issues converting mesh to polysurface. Please advise. Thanks!

Topography.3dm (183.4 KB) terrain_mesh.gh (28.1 KB)