creo4 config.pro option documentation for: INTF2D_OUT_ACAD_ELLIPSES 
intf2d_out_acad_ellipses
yes
*
, no
Controls the export of ellipses to the DXF and DWG file formats.
yes
- Exports the ellipses in the drawing as is by default to the DXF or DWG file.
no
- Exports the ellipses as splines.