Select CATIA v4 from the File>Export submenu. You are now presented with a selection menu that allows you to select arcs, conics, lines, polylines, splines, NURB splines, sheet bodies and solids to export.

Select the entities or objects you wish to export. The Export CATIA v4 Model File or Export File box appears. Through this dialog you are able to set export options and export the selected entities to a CATIA v4 file

Click the Options button. The Catia v4 Export Options dialog appears.

Select the desired settings on the dialog and click OK.

Enter a filename for the exported file and click Save.