after you finish the step 12 or 14, you can extract the curves from solid body.just follow the step as below: : Q- }( L8 F9 S: l- _, Q% k. Y1: make new layer for new curve. # p& A7 l% ?$ H* X2: under modeling, choose Insert--Curve from Bodies---Extract---Edge Curves---All in Face, then select the face of solid bo dy,---ok---0k---Cancel, leave the Extract curve dialoge. / r4 I9 f4 `0 m9 H" y0 ~3. make the solid layer invisible but the new layer of new curve selectable or work. 5 H' o$ K$ S+ A7 N: X/ G3 \. c4. that's all.