How to create this contour form ?

 From:  Frenchy Pilou (PILOU)
10161.20 
You can also consider SubDiv by Max Smirnov :)
http://moi3d.com/forum/index.php?webtag=MOI&msg=9689.1

Not exactly what do you want but...
Volume must be only external surfaces trimed without nothing inside!

EDITED: 16 Feb 2021 by PILOU