FLAT — Flatten to Z=0

Flattens selected objects to elevation zero in place, handling lines, arcs, circles, text, blocks and polyline elevation/thickness. Cleans up 3D survey data before 2D plotting. Software: AutoCAD (AutoLISP). Author: Hydro Engineer (mf4633). Licence: MIT. Source: https://github.com/mf4633/C3D-AutoCAD