thin tangent lines in illustration output

 From:  Frenchy Pilou (PILOU)
10937.7 
It's not the same result that this old "one line" ? (by Max Smirnov) except the layers...
http://moi3d.com/forum/index.php?webtag=MOI&msg=7912.4
(not re-tested :)

EDITED: 28 Jun 2023 by PILOU