Dave, first thanks for helping. What I have is all custom interiors connected to exterior cells in Tamriel. So there was never any vanilla mesh inside the mod I call the Warehouse or the other I call the Bedroom. The warehouse has four merchants who have no additional packages running yet so they just stay at their stations working or wander around and idle. The Bedroom has a housecarl who lounges in varios spots around the living room all day with breaks for breakfast, lunch and dinner and the housekeepers have packages that keep them walking around sweeping with meal breaks as well. Running as esms, the interiors seem to work as intended but not the esp exteriors. Running as esp, both interior and exterior has troubles. The way I test is to leave the interior, fast travel away and return with a follower. It is the follower who shows me whether things are working. In the esp versions, once I return, she will enter with me but stop in her tracks if I get too far away from her. When we enter through one of the doors from a player house, she generally spawns a long way across the room and won't come to me. She generally won't follow me outside either until I walk into an adjoining cell and then she comes running up to me. On the other hand, I can quicksave, exit the game, return to the quicksave and everything is peachy inside and out. Until I move away and return.
I just checked the bedroom exterior file in TESVSnip and the only navm that does not have a vanilla id is the mesh on the balcony. My general rule for navmeshing around vanilla mesh is to try and retain as much of the vanilla mesh around the cell edges as I can and work in from that. Evidently, that preserves the vanilla ids. I'm going to try connecting the balcony like you suggested above and see if that merges it with the vanilla and fixes the problem for the Bedroom. I think that would be a possible test of your theory if I am understanding what you said in your first post today.

I'm curious about something else. What happens if you just change the form ID of the custom NAVM to start with 00?

probably a CTD, but a bad idea either way

00 records means it's editing something in skyrim.esm, if the form ID matches something in the master esm, it will overwrite it (including something unrelated like a cabbage for example). if it doesn't match anything i believe it will CTD (not 100% sure)

fasttravel will work From an interior to an Exterior. 100% guaranteed, i have this working on my file right now. Interior to Interior, not so much (although i think some people have gotten this to work somehow, could be related to whether or not interior allows fast travel).

i believe fast travelling from tamriel into an interior should work for the most part, but if not you can actually build an interior in a worldspace insteaf of an interior cell and it will work 100% guaranteed plus bring your horse parked exactly where you want it (in addition to directly fast travelling into your interior space instead of outside the door, which would actually reduce the number of load screens).

so the "vestibule" could actually be your entire interior and not just a buffer cell in order to minimize the loading screens. the good thing about worldspaces, is that you can place your fast travel marker inside the worldspace itself and still have it visible in tamriels world map (like whiterun, etc), right outside your interior cell's door if you are still using an interior cell (so it would not have to load any additional load screens than what is currently happening now)

and yes, this would not benefit mods like open cities in any way, but it works for those who are finding out the hard way that the esm/esp workaround is not the final solution to the problem




if anything is to be taken away from this thread (series of threads) is that we can now confirm that there are SEVERAL navmesh-related bugs, not just one single "navmesh bug" and they afffect BOTH esm and esp files to varying degrees.

bethesda has only acknowledged "a" navmesh bug, although the root cause of all these bugs may be related to the same thing (but we don't know that for sure), and fixing the esp bug may possibly render the esm problems obsolete for most mods

That is PRECISELY the type of instance I believe would be fixed! Thanks for gettin involved! Some of the footage I recorded is me creating two tri's connecting a balcony's nav with the sidewalk below it (using near-vertical tri's... wherever they fell by simply connecting the existing vertices). Finalized and saved... that cell was fixed, simple as that (shown in 10f; Cell 42,-24 in Tamriel-Riften). After it worked, I went back and deleted those two tri's.. to see if I could evoke the NavMesh Bug again; but it STILL worked... which was more pleasant a surprise than just triggering the bug! (11a showed this) I also added another balcony (island navMesh)...trying to trigger it AGAIN, with completely custom (NOT ever linked to nilla-nav), and IT worked as well; leading me to believe that once fixed, the navMesh bug doesn't return (at least in this instance).

But the behavior you're describing sounds like the NavMesh Bug alright... I just hadn't heard a case that happens through a door. It's usually an exterior cell one fast-trav's to or otherwise approaches from the exterior. It kinda makes sense... in testing the Open Cities mod, I found that actors set to exit a door into a bugged cell would have their AI broken and would 'wander' (in THAT case, up to the party balcony). What is the exterior cell(s) you modify? If 'wilderness', what are the coords?

Applying those results to your mod, your follower's AI would be broken, and she would wander - probably to the nearest Vanilla navMesh if any is still left in that cell. Now this is bona fide nilla-nav... not just a NAVM FormID #. I'm talking actual tri's which are Vanilla and have never been touched by modders' mice. If there isn't any TRUE nilla-nav in the same cell, the follower will probably wind up on the spot with the highest navMesh (like a balcony or hill). After moving far enough away, the follower's auto-correcting teleport kicks in (maybe when you cross a cell's border... but I think it's a function of proximity/within radius of the actor). Of course... if you can't find her ANYWHERE in that cell (tcl inside statics if there are buildings or walls), I suppose she never came through the door at all - which is something I haven't seen yet.

I think you said everything's fine with the interiors... as would be expected. I've never heard of an instance of interior NavMesh Bug... that may garner support for its own Springer-esque talk-show should one be found! So hopefully that balcony will work wonders for ya.

Amethyst: NOW I get the vestibule thing... you're talking about a 'small world' worldSpace.. kinda like the Vanilla Cities are (only smaller I assume). So you'd have your horse, as you said... then have the interior of the house right there seamless with the exterior (like an 'Open Cities' just for one building... only you can't just stroll up.. only trig/script/fast-trav). Or link to the more-detailed interior from there, if the immediate exterior of the house is already burning the GPU. Excellent ideas! This is the kinda thing I'll be needing for a future mod I want to do... but that's in the WAY off future.

[EDIT: about changing the FormIDs to 00... I kinda agree with Amethyst in that it probably won't work, and may cause MORE problems. If you DO want to try it, make sure you do a search for whatever FormID you want to set it to in Skyrim.esm first. It must be unique or will be guaranteed to bug something up. Maybe it'll work though... won't take long to try! EDIT2: You also need to change the data in the corresponding NVMI subrecord... the 1st four bytes are the NAVM FormID backwards (4E 38 10 00 would be the FormID 0010384E). There's always one NVMI per NAVM.]

You can, but it has some drawbacks. I built one in Whiterun, but it doesn't keep out rain and snow. It also gets dark at night and light during the day, although you are completely surrounded by walls.

If you can think of any way to solve this, please let me know.

in custom worldspaces, you can turn off weather and even the sky entirely, or create your own weather that never rains or snows or even has day/night cycles that are exactly the same lighting conditions regardless of time of day, so this would not work for vanilla worldspaces (using vanilla worldspace would defeat the point of the workaround for that matter)

i actually have a working permanent sunset with no precipitation that runs 24/7 inside an interior cell by manipulating weather systems, so it should work for worldspaces even easier (because weather systems are already built in)

Tamb0: you would have to set the region in that area to use a certain lighting template... one which has no precip or skybox. I THINK you can do this with exteriors, but it's been a while since I messed wih weather and lights/etc. I DO know that if you set a "no precip" weather type, you WILL occasionally get precip in the LOD (snow off in the distance which disappears as you get closer).

I actually did the reverse of what you want I think... I wanted day/night for my interior intentionally, whereas I think you want to get rid of it. The premise should be the same though... set the region (of an exterior worldSpace) with a certain weather type, which has a certain light template assigned to it (my interior was a lot easier than that; regions may have another whole SLEW of issues waiting for ya!).

Okay, i tried changing the form ID for the custom mesh and it didn't crash or anthing, but it didn't fix the navmesh problem either. So I went back to the original version and tried Dave's suggestion, which, if I understand it correctly is to tie the custom mesh to the vanilla mesh and end up with a NAVM record that has the vanilla id. That worked to combine the meshes into one NAVM with the vanilla id. Then when I finalized, it created a new NAVM with a custom form id that says it has 0 tris. So do I snip that and its related NAVI entry?

lol, now you're talking way over my head.
I've not long started modding, well ES modding (done some CS modding). Worldspaces and regions are on my "to do" list.

Oops. sorry, no it didn't work. I went back and loaded the file after looking at it in TESVSnip and it has a separate NavMesh record that is not empty again and has a new custom 03 Form ID although it is still connected to the vanilla mesh that has the 00 id.

The info the cellViewWindow shows is kinda buggy itself... especially regarding navMesh references. After you finalize the cell, exit the navMesh toolbar, then save the ESP. If you THEN click on another cell (in the cellViewWindow), then click back on the cell you just messed with, it SHOULD now show the proper data for the navMesh (FormIDs and # of tri's).

And yes, you got it right. The point is to merge your 'island' into a Vanilla NAVM record. I found that you HAVE to select two Vanilla vertices FIRST, then select the third vertex (to form a connecting tri by pressing "A") on the custom navMesh. Then, (if they aren't already selected) select one of the Vanilla vertices and the custom vertex you just made a tri with, then select another custom vertex and form the second connecting tri. Finalize, exit navBar, save, test. If you select two custom vertices first (then one nilla-vertex), you will convert your entire nilla-nav to a custom ref... which would make the problem worse if ever anything can... besides a movie entitled "Big NavMesh's House".

I don't think you need to make the second 'connecting' tri to actually get the ref to convert... I do it anyway just to make sure. Also, one time this didn't work (simply connecting the custom into a Vanilla)... I had to delete the custom and rebuild by adding onto the Vanilla. So if it doesn't work by simply connecting it (and winding up with a Vanilla ref), try deleting the balcony navMesh altogether and test the mod as-is. If it works, then you know it's related to the balcony (which is your only non-nilla-nav in that cell, correct?)... if not, it may be changes you made to nilla-nav; or something different altogether.

Also, if you don't already, I would adopt strick version-control on your ESPs... they quickly get confusing with various changes tried and different combinations. I copy the ESP off to a new filename each time a new change is saved (and I keep saving the same ESP name in the CK).. that's why those test files are 10f.. 15a.. etc...

Ive deleted the custom off the balcony altogether and I am trying to get it to work by navmeshing from the existing vanilla mesh. It starts off looking good but it keeps splitting them after I get halfway done or so. I thought I had it once and saved it and it split it during the save. It is clearly connected by a tri but I think you just said to make two connections. I'll try that, but first I think I am going to test it without mesh on the balcony and see if your theory is correct. If the cell functions correctly, it might be worth leaving the mesh off of the balcony till they fix the problem. (if they fix the problem)

OK. It doesn't work for me anyway. I left off the separate custom navmesh completely jsut keeping the mesh that is part of the Vanilla form ID and it behaves just as it did. It works just fine if you enter the cell directly on loading the game. Everything is peachy. But leave the cell by fast travel or door teleport and return, and it's screwed. I have changed my observation from it is behaving as if there is vanilla mesh to it behaves as if there is no mesh at all. The follower spawns at the center of the cell and only follows if you get close to her and don't get too far away. Same thing the interior cells do if I run them from an esp. Esm seems fine. I really think the only logical solution at this point is to generate an ONAM list and run the whole thing as an esm, but that leaves the Workshop out. And I started this round of testing from a very old savegame from before I had any mods installed.

So with the cell's navMesh completely reverted back to ONLY Vanilla (ie: deleting the NAVMs & their NVMIs using TESvSnip), your follower doesn't spawn & escort properly (after having re-finalized the cell for your door)? Where does your door exit to? I'm still kinda not sure of what you mean by having to be close for the follower to escort... I HAVE seen a little of what you're talking about, but I figured it was just the way followers' AI was normally.

If you haven't already, try linking the doors to your interiors to another cell. Just plunk down the doors and their markers somewhere in a nearby (unedited) Vanilla cell and finalize it. Exit the navBar and save the ESP, then test it. If even THAT doesn't work, then you may have to find yet-even-more-alternative solutions until the official fix. The main thing is to find a place where it will work in the simplest of setups; then move it closer to where you want it to be, and make it more complex AFTER the basic setup is working (just a door placed on virgin-nilla-nav and that otherwise-virgin-cell finalized).

Regarding Steam and ESMs... I think someone said you can upload an ESM renamed as an ESP. So if you added an ONAM, and left explicit instructions for your users to change the filename, you could do it. This kinda defeats the purpose of Steam though... in my opinion (it being a one-click solution for mod-users).

About saveGames - I've found the best way to test anything completely free of saveGame corruption is to use the console directly from the Title Screen (NOT loading a saveGame at all). "COC" to your modded interior, exit and FTR... should trigger the bug if anything at all will. (Use "tmm 1" in the console to turn on all map markers for fast-trav) I doubt this is your problem, as saveGame corruption usually causes immediate CTD... not the NavMesh Bug after FTR.

I'll get some of that video footage together... and record some with a follower too. It'll be a lot easier to explain with a visual aid to refer to. Which Vanilla cells are you having problems with? I want to mess around with it to see what's up... so far everyone that I know of has problems in the same specific areas (as opposed to EVERYWHERE, implying a universal bug), so let's see if this holds true.

I just want to add that after playing out an unrelated quest and coming back to the mod-testing, I've noticed that my follower gets stuck in one place in the interior (just as described by others) - while there are random disappearances of entire meshes in the modified exterior. Part of the problem seems to be related to savegames (suggested by Super Lucky Dave) only in my case I've got the corrupted/uncorrupted savegames the other way around it seems. The other part of the problem is how the last fix patched the game for some savegames and broke it for others. This suggests to me that the savegames may be constructed to an ambiguous standard so that the game does not always account the different ways the same data might be presented by the savegame. In any case, I've an idea from some of my monkeying around in TESCS4.
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I think it worth taking a look at the NavMesh in-game when it is malfunctioning and the console command, http://www.creationkit.com/Navmesh_Draw_Mode can do this nicely. Or it could in Oblivion. Although documented for Skyrim, I don't seem to be able to get this to work in Skyrim (unlike other console commands). Is anyone else having problems with this?
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I think it would be useful to find out if any of the NavMesh actually gets rendered when the bug makes an appearance - which is why I was interested in using the http://www.creationkit.com/Navmesh_Draw_Mode console command...

It was probably one of the many console commands that were removed from the TESV executable.

That's too bad. http://www.creationkit.com/Navmesh_Draw_Mode would have been a very useful way to look at this NavMesh bug and find out something more about what is going on...

In the current version, with the interior in an esm, the problem I am working on is the exterior, which is an esp. The interior has the same problem when it is run from an esp, but the entire interior is custom. There is no vanilla to work off of so I didn't think your fix would apply to it. The exterior is in a vanilla cell in Tamriel. I have deleted (NAVM and NAVI) all references to the custom navmesh. The vanilla navmesh has been modified but retains its 00 form ID. I am triggering the problem by either fast travel from anywhere on the map, or by entering the house and exiting back to the exterior so I don't really think the door link is an issue. If I save the game and quit to dt, everything works fine on load up or on the first visit if the save is somewhere else, but if I leave and return, the follower spawns in the center under the house and following is messed up. If you put a follower into a cell with no navmesh, they will not come to you until you get close, but they will follow you if you stay within a pretty short range. That is what she is doing so my, probably unfounded, conclusion is that there is no navmesh at all.

Yeah, I was watching some of that discussion and it concerns me to use the CK to upload an esm disguised as an esp. I have already had issues with the process of uploading to Steam and the surprise corruption of the resulting file. On one of my updates, the CK glitched the file in both the upload and what was open in the CK. I did not notice until I had already saved the glitch and gone in to test the download in the game. It had totally removed the navmesh and all external references, like merchant chests for example, and assigned new form ids to everything. Which is nearly fatal on Steam since it started updating every user that was online. I was pretty new to the mod process so I had no backup of that particular version. I just fixed the glitched file and did not realize that all of the form ids had changed. Needless to say, every user lost anything they had in the mod and it is intended to be a storage mod - a huge warehouse for stuff. Also needless to say, I no longer trust the upload process in the CK, and keep multiple backups, but we are stuck with it since Beth and Valve decided that should be the only way to get mods onto Steam. Rant over.

Anyway, I am not going to run the risk of uploading file hacks on Steam since subscribers have no option but to go along with it. I doubt anyone is actually doing that. I think that would be exceptionally rude and a total disaster. A large percentage of users would just assume the mod was no longer functional and move on rather than look for instructions on how to fix it, losing anything they had in the mod. Remember on Steam, the mod files update automatically without the user ever seeing the mod page or any notices or instructions. We have no reliable way I am aware of to give the users fair warning of any changes. At least on Nexus, the description shows up in NMM when they highlight the mod file looking for updates and they have to go to the mod page to get the files. OK, rant really over. Sorry, that is pretty much getting off topic here.

There is nothing stopping them from putting them back into the executable though, but yeah that would have possibly shed much needed light on this situation.

Does anyone know if gamesas has a timeframe for another attempt at solving the navmesh bug? Have they said anything since the last patch? It almost seems futile to continue building a lvl if it is just gonna blow away the mesh.

That's what I hope too!
I'm working on a little enhancement for Breezehome. For those who understand the german language, here is a http://forum.scharesoft.de/showthread.php?43983-Trebrons-Brisenheim-Hobbykeller.
The NavMesh bug (entering the house a second time causes a CTD) hits me in a very early state of modding on my crafting cellar, so I decided not to change or work on the NavMesh till it gets fixed.

At an advanced state of progress the same problems occur that http://www.gamesas.com/topic/1361767-navmesh-bugs-part-iii/page__st__90__p__20603093#entry20603093 when she ended in a black plane.
Like her, I can hear the NPCs and the opening of the door.
In my case it looks like I was teleported into the void. (http://img829.imageshack.us/img829/3383/012wrongway.jpg)
In the picture you can see the activation button of the Interior-door of Breezehome (translation: Open -Whiterun) after I tried to leave the house and after the loadscreen.
When this happens, I can save the game, open the console and use the coc command or exit the game.
But when I klick on the button that you can see in the picture, or do other things like opening the map, the result is the http://www.gamesas.com/topic/1361767-navmesh-bugs-part-iii/page__view__findpost__p__20603093.

I am not a newbie, I spend a lot of time modding with the CS for an Oblivion mod and I know that it is better to save your progress very often.
Usually I duplicate a functioning ESP, do changes for half an hour, backup the ESP an test my changes Ingame.
Sometimes I find myself lost in the void when I tried to leave Breezehome, sometimes not.
This happens even after little changes in the Interior, for example adding 4 or 5 new statics.
Switching back to an older and not corrupted Version of the ESP and doing the same changes will somtimes produce an ESP without a teleport into the void!
It doesn't matter if I use a clean savegame, enter the Interior with a follower or not and if there are NPC's in the house or not.

Does anyone know if this is a part of the navMesh Bug too?
I would be glad, if someone of you guys have an idea how I can solve the problem with these void teleportations.


@SLuckyD:
Thank you for your POTENTIAL NAVMESH BUG FIX.
I will try your workaround, as soon as I get rid of those void teleportations.
Btw: Do I have your permission to post your POTENTIAL NAVMESH BUG FIX in a German Forum?

AFAIK, the crashes have been fixed already in the latest version. At least I haven't had any of them lately, and that trying tons of house mods.

I'm about to begin to build a new home from scratch myself But I don't plan to navmesh* it for now (in any case, it's mostly for personal use, and I don't use companions, or plan to put any NPC inside...but I'll put the navmeshes and publish it if it's good enough).

*Unless they're required to properly use the house, of course. I'm still new at the CK

This is a memory bug that appears when mods start growing in size. It's to do with the game not flushing the memory cache/buffers or something like that.
Usually, it only happens when moving from an interior cell to another worldspace, but not Tamriel for some reason. Moving from interior cell to interior cell also seems to be fine.

What you have to do is set up an empty cell as a gateway to the exterior worldspace. This will flush the memory cache and then move you to the outside world.

Read more here -

http://www.gamesas.com/topic/1362739-grey-screen-on-coc-to-towns/