by toprob » Fri Sep 14, 2018 9:50 am
The second-simplest way(*!) is to duplicate the Prepar3d v4 registry entry here (AppPath key):
HKEY_CURRENT_USER\Software\Lockheed Martin\Prepar3D v4
...and call it 'Prepar3D v3'. (The simplest way is to just change the '4' to a '3' in the above registry, install the scenery, then change it back.)
That might not be what you want to do if you are wary of messing up your current install. So you can change that registry entry to a safer location if you wish. The sub installer does allow you to choose the location to install the scenery the first time, so it should work to install it directly, though. Godzone P3Dv3 installers do use a funny way to organise the install location, which is better served with the add-on.xml method now...
Note that you may need to manually activate the scenery as well. I'd certainly recommend using add-on.xml to do this if you are keen to do it that way. If you need any help, let me know.
(*!) anyone else wanting to try this, you will need a level of competency editing the Registry etc!
EDIT: reading this back, it all makes sense, but there are few things that people should be aware of before going ahead and installing other stuff in Prepar3d v4...
The Subscription has quite simple installers, since it is basically 99% photoscenery. However other scenery might not be so simple, so trying this method with anything else is fraught with peril! (I always wanted to say that.)
Prepar3d is great in that it is almost a requirement to install stuff outside the simulator system. However it took me till Prepar3d v4 to really embrace this, so with v3 some files were still installed within the simulator system. These were things like 'AFCAD' files, in scenery\world\scenery, 'global' textures, and of course the occasional hack of Orbx files. A 'modern' P3Dv4 installer shouldn't do any of these things except the FTX hacks, as Orbx still install into the sim system. I don't think that doing any of this is harmful, and it should all still work, but it ain't ideal.
The method I've shown above really works best installing Prepar3d v3 scenery into v4. My FSX installers require some old hacks which don't really work in Prepar3d, and maybe shouldn't be used at all. Again, though, probably not dangerous, just stupid...
One thing which the Sub installers do in Prepar3d v3 is to actually call Prepar3d.exe using a command-line to add and activate the scenery in the library, and it is possible that this will still work using this method, in which case you won't need to manually activate the scenery. However I haven't tried this, and I won't be doing so any time soon. (The command-line stays the same, so I can't see any reason why it wouldn't work.)
However if you want to use add-on.xml, then you will need to remove the sub scenery from the Scenery Library first.
What I'm trying to say, all this is at your own risk! What's the worst that can happen? Probably if you destroy your Registry, your computer will be pretty dead...