I just tried this out today, and it seams to work just fine on my Mac with macOS Catalina
First, navigate to “Preferences” in F360 under in top right corner, click “Manufacture” and select “Enable Cloud Libraries” on.
Select “Show data panel” in top right corner of F360, click “Assets” under “Libraries”, then “CAMPosts”. Click “Upload” and select the two files “DIYCNC_Common.js” and “DIYCNC_Marlin20.cps”, and both will be uploaded together (I don’t know if that’s important).
When you are ready with your design and the tool path process, right click the machining step in the F360 browser and select “Post process”. In the dialog, select “My Cloud Posts” and “DIYCNC Milling/Laser - Marlin” should show up as an option.
The gcode was generated and I opened it up in an text editor (Vim). It seamed reasonable, but I havn’t tested it on my MPCNC yet.
I hope this may be helpful.
Cheers Marius