Are you talking about FreeCAD? One solution is to generate meshes yourself, then export them to dxf. To generate meshes...

Commenting post 285: Are you talking about FreeCAD? One solution is to generate meshes yourself, then export them to dxf. To generate meshes from shapes you have a tool in the Mesh workbench, that asks you for a tolerance value. That value controls how many facets are generated from curved faces.