How to Mod - LitR: PreVisibines

What Are Previsibines?

Previsibines is a slang term for previs/precombines which are a couple of ways that the game improves performance. Both of these are tricks that the game engine uses to pre-optimize things. The main thing you need to understand, is that these changes live in the CELL record -> what this means, is that ANYTHING that adds, removes, or moves something in the world, or randomly copies a CELL record as an ITM will conflict. This is why the general advice is that ANYTHING you add to LitR goes ABOVE PRP. The primary symptom of broken previsibines are large portions of the world that flicker in and out as you move.

Previsibines in LitR

As of 6.4 (in pre-release as of the writing of this), LitR uses PRP v74, and already includes major patches against PRP that cover most of the world (Beantown Interiors/Tales from the Commonwealth, South of the Sea, Show No Mercy). Anything you want to add that has a PRP patch ALSO needs to not conflict with those existing patches. In LitR, all of the Previs related mods and patches are sorted into the Previs Category in MO2.

Scrapping/Settlement Repair Mods

I've seen this mentioned a lot in the past, although it's been less-so since SS2 came out. In general, there are two types of scrapping mods- those that regenerate precombines which allow you to scrap more things (which are more or less safe but will reduce performance in settlements), and those that just disable them completely (which really aren't safe at all, and will completely destroy performance in settlements). Because regerating precombines requries patching against PRP, it will almost always conflict with the existing PRP patches already in the list. LitR simply isn't a list that's built for a player-driven settlement sandbox experience.

How to Test whether your Precombines are broken

There are two relatively simple ways to determine whether a mod breaks precombines. First, open the mod up in fo4edit, and check under CELL and WRLD categories. If it makes changes to REFR records that are surrounded in [brackets], then chances are it is breaking precombines. To verify in-game, go to the cell in question, and run the console command 'TPC' two times. TPC stands for Toggle PreCulling, which toggles the precombine system. When you turn it back on, if precombines are broken in teh current cell you'll recieve the message 'Preculing enabled, but disabled for the current cell'.

Learn More

Previsibines is a DEEP topic to get into. My strong recommendation is to simply avoid mods that either break or rebuild them when modifying LitR. It's an area I've tried to work in, but failed. If you really want to learn more check out https://www.nexusmods.com/fallout4/mods/69978?tab=articles