Use CoordinateSystemService from Civil 3D API:
For , there is no native built-in command to directly import KML/KMZ files . Unlike later versions (2019+), which include the MAPIMPORT "Google KML" option, users of the 2018 release must use workarounds like format conversion or third-party add-ons. Option 1: Convert to Shapefile (Recommended) import kml to autocad civil 3d 2018
public ObjectId CreateCogoPoint(double northing, double easting, double elevation, Database db, Transaction tr) Use CoordinateSystemService from Civil 3D API: For ,
Allow users to import geographic data from a KML file (points, lines, polygons) into Civil 3D 2018 as native objects: import kml to autocad civil 3d 2018