Hi @RitchieFromParis ,
It's nice to hear from you again. Ratsnest is no longer necessary in Fusion because your airwires are constantly being re-calculated and the polygon fill is controlled as a separate function under the polygon menu.
With that said the RATSNEST command is available through the command line. I've spent enough time in Fusion 360 that I don't think about RATSNEST anymore.
Let me know if there's anything else I can do for you.
Best Regards,

Hi Jorge, nice to hear again,
Ok good news...
I realized a complete project in Fusion, there many interesting things, but see my other post.
Thanks Jorge again.
Best