Unofficial Skyrim Special Edition Patch

It's a general game engine bug. Windhelm and Solitude appear to be the most likely to be affected because of how far their terrain meshes float over the underlying landscape. For reasons unknown a game update along the way did something to the priority loading of meshes, terrain, and NPCs that now has a chance for them to spawn under the city meshes. Assuming they don't die from a fall they will correct their positioning once everything loads.

We added a failsafe trigger in Solitude under the ground in the places most likely to have an issue and that seems to have solved it for the most part there because of how we positioned it to load where you're most likely to walk up to it.

Sounds like we may need to add one in Windhelm too.

I had Nilsine Shatter-Shield and Angrenor Once-Honored die in the same way in Windhelm months back on my current save. Also, in Solitude, Silana Petreia seems to die relatively easily despite the fix that was put in place. It seems that there's only so much that can be done, although less NPCs seem to die in Solitude now than in the past prior to the fix. Somehow Fralia Gray-Mine died in a similar way in Whiterun very early on breaking the quest with her sons. This engine bug seems to be able to bypass the protected and maybe essential flags in some cases, possibly because the NPCs somehow get trapped underneath the playable area.

Essential and protected ones should survive the fall, they'll just be stuck below the playable area until you leave the city. Which is still problematic but as you say there's not much we can do about it except report it to the devs.

Thanks for the informative comments. In my 20+ tests so far, the only way I've managed to avoid the problem is to be inside during their walking period(s).

The only reason that I'd have any idea they were dead was a courier telling me that Angrenor had given me an inheritance. I've always given him a coin outside Viola's during "That was always there". So I'd hunted around to figure out how he inexplicably died.

Originally, I'd found Nilsine there near Angrenor under the playable area. And once already dead on the walk outside the Cornerclub, as I'd walked toward Sadri's. Also, as I'd walked from Sadri's toward Candlehearth, Nilsine fell out of the sky near Susanna leaning on the wall outside during that time of day. That was quite a long time after the loading screen (exiting Sadri's). Nilsine has no package that takes her anywhere near the dark quarter, so this is just weird.

Thus, there seem to be two different methods of falling death, both above and below.

Should we keep this open until the Solitude trigger solution is added to Windhelm?

There are plugins (using SKSE) that add a conditional perk to prevent falling death for all creatures and NPCs. Would it be useful for USSEP to instead add something similar to all non-essential or protected NPCs?

Should we try to get aers or meh321 to figure out an engine fix?

(LarannKiar has recently done a similar engine fix for Starfield.)

A working theory has come up. During testing for another mod, an issue with landscape positioning came up which prevented access down a passage in a worldspace type dungeon. It turns out that in the case of that dungeon, the "Small World" flag on the worldspace was the cause. Same kind of situation. Someone walks into the place through the connected load door and the problem manifests.

All 5 of the walled cities have this same flag on their worldspaces, so if the landscape is loading below where it's supposed to be, like maybe above the city worldspace, then a similar issue might occur if the terrain meshes haven't loaded yet but the NPCs have.

The weird thing is, if the player reloads the game while already inside the affected worldspace, the landscape height will be corrected. So it could also be a situation where that change in level is causing it.

Removal of the flag stops the landscape from being in the wrong position. So if this is simply a matter of that being out of place then that's one possible way to address this. It would need testing by someone who is readily able to reproduce the issue though. I haven't been able to do that.

Worth noting that for Open Cities, I resolved the possibility of this by raising the landscape under the exterior parts of the cities. Obviously that would make no difference whatsoever for the vanilla worldspaces.

Note that I've always turned off auto-save of every kind, and always re-load from the Main menu after quit to desktop.

It is very hard to readily reproduce. All my tests were:
1. loading from desktop inside Sadri's or Candlehearth after 12 pm or 4 pm game time,
2. exit,
3. manual save,
4. walking to the other,
5. enter,
6. save,
7. command mode,
8. player.moveto # to see where Nilsine and Angrenor are located.

Nilsine dies most often.

Why wouldn't raising the landscape to just under the meshes work?

Another thought: my previous runs were all on older graphics cards. The first machine I'd bought to play Skyrim had a gtx570. The second machine (for special edition) had a gtx1080. Yep, the only PCs I've bought in ~30 years were for this game.

This is the second machine retrofitted with (used) rtx2080 recommended for Starfield (same bus with added power cable), as the 1080 was barely enough.

I've noticed that other than the initial load, I'll barely see loading screens anymore. It's just a quick black screen blip. Maybe Skyrim is loading NPCs too quickly, instead of waiting for the terrain to finish loading?

Is Blackpete also running a faster graphics card?

Messing with the landscape height won't help and is also not something we'll do in the patch. The Small World flag appears to be the issue as it's been replicated in the other mod I was talking about, and changing that mod to remove the flag has solved the problem.

I have no doubt that the speed of the loading screens is a factor. On my PC with a Gen 5 SSD and a 7900 XTX, there's no time to read the text on them. They literally go by in a blink. That said, I haven't noticed the issue myself anywhere other than Solitude and we added a failsafe there in 2020 which seems to be working.

My current card is a Radeon RX 6700 XT, which most people would probably consider ancient. I don't recall which AMD graphics card I had on my previous PC a few years ago, but it was at least good enough to run Skyrim SE well enough without noticeable problems. Like Arthmoor, the load screens (on my current PC) go by quickly, often too fast to read.

One of my theories on the issue is that fast travel may be a factor. I think Silana died by falling once in Solitude after I fast travelled to the Blue Palace. After I was arrested in Rorikstead and then transferred just outside the jail entrance next to Dragonsreach a guard fell from the sky near the Gildergreen/Temple area. These may have just been coincidences, but I have noticed that fast travel can occasionally cause odd issues. Sometimes the three predators placed in the hills well south of Dawnstar mysteriously appear right in the town near the inn when I fast travel. The problem is none of these examples can be replicated reliably, which is typical of some engine bugs.

Thanks BIackPete. Seems like we all agree it may have something to do with fast loading screens. And likely Small World flag.

Searching, in 2022 Sheson says no idea what Small World flag actually does.

As I never fast travel (since 2013) other than forced by a quest script, haven't seen those effects.

On Touring Carriages, I'd very reliably watched the predators S of Dawnstar travel to town on a preferred path, usually killing low level unique townfolk before the guards could intercept, and discovered some intended prey was below ground. Fixed for USSEP 4.2.6.
https://afktrack.afkmods.com/index.php?a=issues&i=31330

You guys both seem to be more readily able to replicate this. Can you see if this file makes a difference? The flag has been removed from all 5 walled cities.

Attached Files:

437Update.esp