Clarification on combined meshes, cell reset etc.

[damanding]

It's not a big challenge. if you have two mods that modify the same cell you would load them both in the CK with none set to active, and just generate new previs data, and save it as a ptach. it takes all of five minutes. I know that making one for every possible combination out there could potentially be an issue, but you really only need to worry about it if people are complaining about compatibility problems... Not to mention those can be made by third party users and uploaded as a patch mod since it won't contain any of the assets from either mod... just previs data.

That wouldn't be a challenge for the average mod author, but it's very much a challenge for the average mod user and they are by a huge percentage the larger proportion of people on this site. It's unreasonable to expect all users to have mod author levels of knowledge.

[Trosski]

That's Why I have comment sections on my mod pages. I try to accommodate compatibility requests whenever they pop up, which has only been once. Someone was having issues with compatibility between my mod, and a sanctuary bridge fixing mod. I looked at the mod, saw it was full of bug complaints, and decided it was easier to fix the bridge in my own mod instead.

 

I see what you are saying about the average user, and I guess my view of them is kind of skewed. I always thought of myself as the average user... I have been playing since A little before Oblivion(My friend introduced me to Fallout 6 months before Oblivions release), and always played around with the creation kit. Mostly just tweaking armor stats, and XP multipliers. I hadn't put anything out until Skyrim came out, and that was a simple wood chopping mod that increased the amount of wood you could get from 6 to 600. It was a short lived mod, because Beth updated, and it stopped working. I never could get it to work again. And honestly... Aside from my own mods here and there I mostly played vanilla. I found it too much of a pain to search for mods. It wasn't until FO4 that I started looking at the modding community seriously, and decided to contribute.

 

I'm not very skilled, and I am horrible at scripting, so I figure if I can do it, then anyone can.

[damanding]

You're definitely more knowledgeable than the average mod user, even if you don't have as much knowledge as the more advanced mod authors (which I don't either so don't think I'm insulting you).

[shadowslasher410]

I don't know... I've practically torn my hair out trying to make the Mechanist's Lair and Vault 88 try to play nice with no precombined/previsibility. Of course, they are RIDICULOUSLY HUGE CELLS so of course disabling it would create a drop in FPS to near unplayability for some people, and horrible "world blinking syndrome" (occlusion culling) for people even with better computers.

[VIitS]

In order to get an interior cell (especially one like the Mechanist's Lair) to work well without precombineds/previs you would have to go through and add/fix portals and room bounds for the entire damn cell, which would take forever and require a better understanding of how they work than anyone currently working for Bethesda (apparently the guy who made the system left after FO3, and no one has known how to use it completely right since). Either that, or you'd have to go through and remove them all (to fix the occlusion bugs), in which case you'd still have to deal with the performance hit in the particularly large cells.

 

I don't think anyone who knows what they are talking about would deny that you should make new precombineds/previs for large interior cells, but new previs/precombineds in an interior cell can be very finicky, only working some of the time, with no discernible reason why it doesn't other times. I can't help but think that is part of the reason so few mods touch those cells.

 

I'd also agree that it's best to generate new precombineds/previs if you are editing a cell in the middle of Boston or other "cluttered" areas (assuming you need to, of course), as the performance hit in that area is significant for the vast majority of mod users. That said, part of the problem is the CK is a slapped together imitation of the tools they used to make the game (despite any claims they might make otherwise), and some of the more advanced functionalities (like generating new previs/precombineds) seems to be hit or miss as to whether it will work for a given mod author. Hell, I've had to build .ba2 archives for someone before, because every time they tried to make them for the xbox version of the game the CK would crash. As another example, trying to delete a "facial features" category (a brand new one or a vanilla one, with no options or dozens) will cause it to crash every single time. I had to open my mod in xEdit to do it, then swap back to the CK to continue because xEdit is not really made to work with stupidly large records like the human race record.

 

 

Outside of the aforementioned cells, I prefer to err on the side of compatibility. So far, the only bugs I've had were unrelated to previs/precombineds, barring issues with another mod loading after mine. What previs/precombineds a mod uses is set in the cell record, so load order problems would still exist even if I generated new previs/precombineds.

 

Trosski, as I have spent a lot of time figuring these things out, I wanted to clarify a few things in response to your earlier comments:

 

 

The cell reset/sprinting bug (when it existed) occurred any time you touched the previs/precombineds in an esp, but did not happen if you did so with an esm. I can't say for certain whether or not it would have occurred if you made new precombineds/previs, as that functionality wasn't actually working in the CK by the time the bug was fixed.

 

The ITM method of disabling previs/precombineds takes advantage of a purposefully implemented workaround Bethesda implemented for the sole purpose of mod compatibility. And while a mod like Spring Cleaning accomplished it in a very messy way (due to Nverjos being the first to really discover it, and not updating the mod since), it only actually requires a single reference to a record that is part of a combined mesh to trigger it. As long as a mod author knows which records have an effect (easy now that xEdit will list if a given placed object record is in a precombined mesh, and if so which one), they will only need a single ITM record to trigger the effect.

 

But that doesn't really matter, since making actual edits to a record that was part of a precombined mesh will also disable previs/precombineds. So the only mods that would have any reason to use the ITM method would be scrap mods. If your mod edits things in such a way that you edit a precombined record, you don't need any Identical to Master records. If it doesn't, then you don't need the precombineds/previs to be disabled (and it's unlikely you've made enough edits that adding your stuff to previs/precombineds will make an appreciable difference).

 

On top of that, Kuroitsune and/or shadowslasher410 (not sure which one) figured out what edits you need to make to a cell record to disable previs/precombineds without your mod having to touch a single placed object record (deleting the VISI, RVIS, PCMB, XPRI, and XCRI fields using xEdit, in case anyone is curious). The advantage to this method is that previs will stay disabled even if a person is using the bUseCombinedObjects=0 ini edit, which disables the workaround mentioned and is the primary cause of the occlusion bugs people report.

 

As for compatibility issues from making new previs/precombineds, they extend beyond the fact that previs is generated for 3x3 cell grids (and the file size issues for xbox1/unusability on PS4). If a mod edits a vanilla mesh, the changes won't show in a precombined mesh. That's the sole reason I even had to make an esp for my Red Rocket mod. Edited textures will show up, not not edited meshes.

 

 

 

To sum up, the only reason to generate new previs/precombineds (excluding interior cells) is for performance improvements, and you have to balance that against the size/compatibility issues caused by doing so. It's best to just avoid vanilla interior cells if you can, because they are just a pain to work with.

[damanding]

Thanks for such a useful explanation Vlits. :) I've struggled to understand not only the technical details behind this, but perhaps more importantly when it's best to regen vs not regen precombined/previs and your explanation makes it all make so much more sense.

[VIitS]

Thanks for such a useful explanation Vlits. :smile: I've struggled to understand not only the technical details behind this, but perhaps more importantly when it's best to regen vs not regen precombined/previs and your explanation makes it all make so much more sense.

Happy to help. I got sick of UPDATES TO THE VANILLA GAME somehow breaking Spring Cleaning (wanted to figure out if I could trim it down a bit too), so I put some work into figuring out precisely how SpringCleaning.esm worked.

 

I still don't understand how that was happening, when the patch I made seems to work consistently through game updates. Everything I know about modding for FO4 says it shouldn't matter, but it does. So even if you only use Spring Cleaning and no other mods, you might need my patch for compatibility with the current version of the vanilla game. GG, Bethesda.

[Trosski]

Well, I know that as far as my mod is concerned I need to generate precombine and previs data, or there is occlusion culling all over the place. Not to mention I have completely redone the red rocket station's 3d model to make the pump arms scrappable.

 

I know that everything you mentioned as far as disabling the precombine and previs system may work for some, but my pc in no way can handle rendering cells without it. I get horrible FPS, and occlusions culling makes the game down right unplayable. I would rather not put something out for one system, than make some buggy crap. Especially when it's so easy to select "Precombine Geometry for current cell", and "generate visibility for loaded area" from their respective drop down menus.

 

My mod may never make it to PS4, but it works great on PC and XBone, and who knows... maybe consumers will make them change their mind about custom assets by not buying sony products in the future(I doubt it).

 

Plus when you precombine it gets rid of the issue where objects that normally sink into the ground (Like cement pillars) can't in areas where stuff was removed.