Sorry only for Windows 10 users but that is terrific of easy possibilities! :)

Just discovered that!

Use FBX export from Moi and voilà!

(if you want make the inverse Paint 3D --> Moi3D: load the FBX from Paint 3D inside the free Blender
then export in OBJ ---> then Obj Import by Max Smirnov inside Moi3D!