Introduction: Exporting Multiple Bodies From Fusion 360 to 3D Printer 2022 Update
To export multiple bodies to a 3D printer using fusion 360 (not intuitive) you have to make a "selection Set" of the bodies first, then when you click on the 3D printer icon under "TOOLS" all of the bodies that are visible will be selected and you can send them to your printer by pressing "OK" in the "3D PRINT" drop-down. If you don't create a "Selection Set" you cannot just drag a square box over them to select multiple bodies or press shift to select multiple bodies. It sucks that its not so easy but whatever, this how you have to do it. Its a lot better than creating strings or a layer between them that is too small for the printer to print.
Supplies
Fusion 360, 3D printer
Step 1:
Refer to introduction