About Exchanging Data Between AutoCAD Civil 3D and Autodesk InfraWorks
You can bring Autodesk InfraWorks data into AutoCAD Civil 3D by referencing a local InfraWorks model or an IMX file that was exported from InfraWorks. You can bring AutoCAD Civil 3D data into InfraWorks by linking to an AutoCAD Civil 3D DWG file as a data source.