Originally Posted by
dotson
I assume you are using AutoCAD MAP 3D, since plain AutoCAD has no provision for this. For the export to work properly your drawing has to be assigned a coordinate system (see the ADESETCRDSYS command). Then it's also critical that your geometry has coordinates that lie within that assigned coordinate system. For example if your drawing system were LL84 (not likely) the coordinates would have to be from -180,-90 to 180,90 (lat/longs).
You may have to check with the original creator of the drawing if it wasn't you, and you may have to enlist the help of a surveyor to transform your drawing. In summary, if it's assigned a system and your drawing coordinates are correct, your KML will hit correctly, otherwise there's not much of it.