Fusion app paths

If you are developing apps for the Fusion app store then it could be useful to know where exactly Fusion is looking for add-in bundles to load, so that you can test the loading on your side. To see what a .bundle should contain you can just download any of the free apps from the Fusion app store. 
Note: on MacOS you have to right-click the .bundle folder and select Show Package Contents to see what's inside it:

The Windows and MacOS file structure is different so the add-in folder locations will be different. But on MacOS we also have two install types of Fusion:
– web install
– Mac App Store (MAS) install

All MAS apps run in a sandbox environment, and they cannot load additional modules from outside their folder structure without user interaction. That's why the MAS version of Fusion is using a different path for Fusion apps.

Windows:
%APPDATA%\Autodesk\ApplicationPlugins

MacOS web install:
~/Library/Application Support/Autodesk/ApplicationPlugins 

MacOS MAS install:
~/Library/Containers/com.autodesk.mas.fusion360/Data/Library/Application Support/Autodesk/ApplicationPlugins 

Note: if you want to use the above paths inside a script on MacOS, you need to deal with the spaces in folder names – e.g. in /Application Support/. Unlike in Windows, here you cannot put the whole string between apostrophes, because then the special character '~' (which means the current user's folder) would not get resolved. So either you can just escape each space character in the string with a backslash '\' e.g.:
~/Library/Application\ Support/Autodesk/ApplicationPlugins
… or put the part after the '~' character between apostrophes:  
~'/Library/Application Support/Autodesk/ApplicationPlugins' 

-Adam