Why and when should you do that?
Sometimes all you have from the client are the drawings from the CAD software. This step is necessary to determine the area of interest and export it to KML/KMZ format. This format is widely used
Open the drawing in Autodesk Civil3D
Draw a boundary with polyline tool around the area of interest to include all the terrain that needs to be mapped
Select only the boundary and copy it
Open a new Drawing
Paste to the original coordinates option
Go to Drawing Settings in the top left corner menu
Set the Coordinate Reference System of the drawing.
Now you can make sure that the project is in the right location by using the GEOMAP command with Aerial satellite data
Once the Civil 3D view is active, go to Toolbox in the left menu and click Miscellaneous Utilities
Click Export KML
Click Next until you reach the export file path
Choose where to export the file
Now you can use the exported KML in Google Earth PRO or in Inflights platform (boundary only).