unable to save parasolid of composite curves

[nzhills]

Hi, I'm very new to this forum. I am experiencing trouble saving a set of composite curves as a parasolid. When I have a wire frame of what I want i click File : Save As and I change the type to parasolid .x_t. On clicking Save an error box comes up saying "The file could not be saved because the part's geometry is not valid for this type of save operation." Can someone tell me what I am doing wrong and how I can rectify this situation?
Best regards
Mark

 

[Cadasio]

I would think you need to create an actual body (solid or surface should do). Currently, your part is "nothing". A parasolid may not have any concept of sketches?