you need a few things
hal's bbb .dll
https://7daystodie.com/forums/showthread.php?7564-Hal-s-Prefab-Editor
watch his tutorials, its easy, use that dll, then you can CLAIM an area, and export it as a prefab.
commands needed:
bbb rp
bbb claim "your prefab name here no spaces" //the default is 33 square spaces, or radius i cant recall, but in the hal tool you can open game backups and click the game type, game save name, player name, make yourself admin, and make your claim bigger, then go back and claim it again.
bbb export // i might be wrong on this one, its like 2am.
you should watch the videos, i cant recall off the top of my head
then use Zombie64 prefab editor
https://7daystodie.com/forums/showthread.php?62501-Prefab-Editor-(Alpha)
to trim down your prefab to just your building, then use HAL again, create an empty world, import your prefab, simplifly, combine, and export.
now you have your building ready, you just need to call it in the RWGMIXER.XML
if you want it to be in cities, then add it to a district, like residental, blah blah blah. or to wilderness if you want it to be in the wild
you will want to save those changes, then start the game, and use the tools; world preview, and type your seed, then explore for your base,
if your hellbent on that seed, then you will have to raise the prob="100.0" to make your building more likely, if you want to guarentee it, you will need to add min_count="1" max_count="1".
so it should work like this:
you have your prefab files:
mcTacoHordeBase.tts // your actual prefab file
mcTacoHordeBase.xml // your settings for your prefab file, biome lock, district lock, trader area etc..
mcTacoHordeBase.pile // not sure what this is actually but i let it live because it might be needed
mcTacoHordeBase.mesh // your distant mesh, so you can see it from a mile away instead of only 10 feet away.
these should already be in your ..7 Days To Die\Data\Prefabs\.. folder
now in your ..7 Days To Die\Data\Config\.. folder
there is rwgmixer.xml its in here that you need to call your prefab in order for a new Random Gen world to render your building
here is my base : <prefab name="mcTacoHordeBase" min_count="1" max_count="1" prob="100.0"/>
just replace mcTacoHordeBase with your prefab file name. dont include the extention:tts,xml,file,mesh. just the name
now remember where you put this is where it will render. do you want it in a city? or wilderness.
add in at the end of a list of like this:
<prefab_rule name="W_POIs_common_Set_A">
<prefab rule="farms" max_count="3" prob="0.2"/>
<prefab name="army_barracks_01" max_count="1" />
<prefab name="xvanilla_army_camp(universal)" max_count="1" />
<prefab name="xcostum_Polarstation(by_magoli)" max_count="1" prob="0.4" />
<prefab name="xcostum_WWHouse(by_IceJudge)" max_count="1" prob="0.4"/>
<prefab name="house_new_mansion_01" max_count="1" prob="0.3" />
<prefab name="xcostum_Safehouse(by_Limodor)" max_count="1" prob="0.4"/>
<prefab name="xcostum_wastelandtrain(by_Horst)" max_count="1" prob="0.4" />
<prefab name="xcostum_TheSect_Followers-of-M(by_magoli)" max_count="1" prob="0.2" />
<prefab name="bombshelter_lg_01" max_count="1" prob="0.2" />
<prefab name="xcostum_FuneralParlor(by_Zombieman)" max_count="1" prob="0.1" />
<prefab rule="AframeHouses" max_count="1" />
<prefab name="dwalls_Beachhouse" max_count="1" />
<prefab name="ozzy_barn" max_count="1" />
<prefab name="silent_ssfarm" max_count="1" />
<prefab name="mcTacoHordeBase" min_count="1" max_count="1" prob="0.1"/>
</prefab_rule>
now like i said, preview your seed and make sure your base is there, then start a game with the seed you verified.
let me know if you need any more help, i have included a link to my homemade prefab using this method, so you can test and explore
enjoy
http://www.mediafire.com/file/j8o691ejsmasbsb/mcTacoHordeBase.zip/file
feel free to ask as many questions as you need, i am here.
EDIT: you dont need to continue using bbb's dll, so make sure you replace it with your original, make a backup of the dll before you install the bbb dll,
only for editing.
. Any help is appreciated!