A popular request is to export geometry in a Civil3D drawing to Google Earth in a KML/KMZ format. This post contains details on how to do it, with a step-by-step procedure for Civil3D. For recent versions of Civil3D, you will want to use the EXPORTKML command because it will support the most object types (including AECC objects). However it has some quirks and this procedure may help iron them out.
