Hello Karsten and Friends
Since the first post of Jotero ,in the forum,
this Minimal Surface (Batwing) has fascinated me;
and I tried to build it in Low Poly with Elephant-
I must say that apart from the modeling
I finally met some difficulties:
the ultimate Polysurf , that apparently
It seemed welded at the edges, in reality
It is not, and once the tool SubD is applied
Produces an unwanted hole in the center
Of the box unit volume- (see pictures)

Therefore I followed a different path:
I exported the STP Polyserf unwelded
In Catia V5 R 21, I welded the surface by lowering
the tolerance of union at 0.01 mm,
I have redone a new file
Stp , which I imported into Moi and I converted
In Mesh Obj ,
I finally imported Obj Mesh into Moi
and in this case the Subd Tool works fine.......

Not happy with the result
I tried to go a different way
for creating the file ....
And in this case, keeping the value fixed
of the board at 10 mm , of the primitive box ,
the polysurf obtained is welded and the final result
seems to me lovely
The entire folder containing the various files
and images for the various steps are at this link:
https://www.mediafire.com/?dsqa83n896gfcia
I used the new Mirror tool, it seems ok
Thanks again to Karsten-

Finally, for those who know and use Catia
I attach the import file of Mesh obj
with the Image and Shape module
and the subsequent thickness of the surface

Have a nice day
al