Ahh yeah I just came back from the editor to post that I figured it out, but THANK YOU yes this definately seems to be the answer (and I appreciate the screenshots etc. makes understanding so much easier).
So to Celludriel - just design your building as a level and then remove any terrain, start points etc so that the level is literally just the building and whatever you want in it. Then create a new level template the way Windmere explains above and choose your building level in the drop down. Then you will have a level template of your building which can be drug into existing maps.
What do you think would be the best way for Celludriel to distribute this though as obviously people will have to add this into the editor as a project in order to access his levels / level templates? This really doesn't fit a mod or addon since it targets the editor... (can a project even be uploaded to Steam Workshop? I suppose it could be zipped up and put on Nexus or the like...)
PS - @Windmere or anyone - is there any method you can think of to turn a prefab, group or level template into a single scenery object? I want to add wall, houses, lights and the like to the GM palette (and other items), but I can't find a good method... or even just groups of existing scenery objects turned into a single object - for example say a table with plates and food on it or shelves with books.
Last edited by JRavens; 01/10/17 05:46 PM.