It's been a while since this thread was last used and I stopped playing FO4 for a few months, but there are two new mods that are so useful for settlement building that I decided to start playing again and post here about them.
Clone My Shack:
https://www.nexusmods.com/fallout4/mods/30822?tab=description
Clipboard:
https://www.nexusmods.com/fallout4/mods/31090//?tab=description
They're copy and paste tools for settlement objects, groups of settlement objects, whole buildings or even whole settlements (although Settlement Blueprints would be better for whole settlements).
Ever spent ages getting something built in a settlement and balked at spending hours doing it again in another settlement? A perfect guard station, a bathhouse, a diner, whatever. No problem with these mods - just copy the structure and everything in it and paste the whole thing somewhere else. In a different settlement if you want. Built a nice bedsit for a settler and balked at doing it 20 more times for just that one settlement? Copy it and paste it 20 times. Or 500 times in 25 different settlements. Got a room decorated just how you want it, dozens or hundreds of pieces of furniture and decoration in just the right places? Want another room the same size decorated the same way? Copy all the items in the room and paste the group of items into another room. They'll all appear in exactly the same layout. All pasted items are functional, so your settlers will sit on the chairs, sleep on the beds, use the workstations, etc.
CMS was the first and initially had more features than Clipboard, but both are in active development and at the moment Clipboard has some features that CMS doesn't have. Clipboard allows exporting and importing of copied things, so you can download rooms, buildings, gardens or whatever that other people have made and paste them into your own settlements. Clipboard has 50 slots that persist over sessions, so you can always have up to 50 patterns available at any time (CMS has 1 slot that isn't persistent, so you have to store copies of stuff you want to keep in a settlement set aside for that purpose). Clipboard has a selection gun option, so you can add individual items to a pattern by shooting them (perfect if, for example, you want to copy the furniture in a room but not the walls) as well as selecting everything in a sphere, cylinder or cuboid of a user-definable size. CMS uses the vanilla bulk selection process, so it copies everything touching the item you select and everything touching those items, etc. Right now, I think Clipboard is better but that could change as they're both in active development.
Both will even copy wiring that's within the selection (although you can't select wiring with Clipboard's selection gun so you'll have to rewire afterwards if you use that selection method).
Pair one of these mods with Place Everywhere and you're golden for settlement building. The only drawbacks to me are that pasting doesn't use any resources and doesn't get you any experience. The latter no longer really matters as I'm L197 from all the building and scavving I've done, but the former grates on me. I'd rather have to use the required resources, so I'm stuck with manually noting the cost of each item in a pattern and disposing of the right amount of each resource after doing the building. The merchants in Diamond City must love me, since I'm selling them thousands of units of various resources for a few hundred caps
Also, the process is pretty slow. Not game-breakingly slow and vastly faster than repeating the building, but it's not like pasting text. For example, pasting a pattern of ~100 items into a room took about 20s on my machine.
