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LOD Meshes and exact localization on the map

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LOD: acronym for Level Of Detail.

Ingame, around the player, the closer terrain and objects are fully rendered, meaning they are using regular full-poly (and eye-candy) meshes. For short: the more all this stuff is distant from the player, the more it is replaced with simplified meshes in order to save performance. As the distance from the player increases, the LOD goes from 4 (very detailed), then 8 (less detailed), then 16 (even less detailed), and then finally 32 (poorly detailed).

LOD files are present in the 'Skyrim - Meshes.bsa' archive. DLCs also bring their own LOD files in their dedicated archives.


Once you have extracted the archives, and for the tamriel worldspace, you can find :

  • a bunch of files in meshes/terrain/tamriel with the '.btr' extension type. They are the landscape LOD meshes.
  • a bunch of files in meshes/terrain/tamriel/objects with the '.bto' extension type. They are the objects LOD meshes (mainly rocks and buildings)

Both can be opened in Nifskope , but let's have a look at the objects '.bto' files. Their names obey to a kind of logic : they're all named TamrielN.X.Y.bto, where N is the accuracy of the LOD (from 4/very detailed, 8, 16 and 32/poorly detailed), and X and Y are the coordinates on the map. The problem is : is there a way to know in which .bto file I can find a specific building/town ? The answer is YES !


I made custom maps for the level 4, 8, 16, 32 LOD files in order to save a lot of time when looking for the coordinates.

All maps for both Skyrim and Solstheim are available at nexus here for Legendary Edition and here for Special Edition. As this is a modder's resource/helper, the files are absolutely identical for both SLE and SSE...

I hope this can be useful for modders who are interested about LOD in these worldspaces.


If you have suggestions for improvements or conveniency, feel free to express.


Please have a look at this topic if you want to learn more about LOD files generation and download fixed vanilla files.

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I'll have a look at it in the next 2 weeks. But, at the moment, and in a goal of 'training', we could try to narrow the .bto files necessary to make a ' true LOD' version of Azura's statue. Even if I'm satisfied with the actual trick, that would be a good challenge, isn't it ?

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First post edited, read it again for new download links. Updates :


- coordinates for ALL LOD pieces.

- proper icons for spots.

- skyrim LOD 8,16,32 maps added.

- solstheim LOD 4, 8, 16, 32 maps added.


Madcat, if you read this, did you intend to make a proper LOD for the Temple of Miraak ?  ;)

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I let the Temple of Miraak LOD bit slide because last I heard there was no progress in figuring out the LOD system.  If this works, then I can pick it back up.


Not sure how to integrate it into the Solstheim LOD texture, unless textures can be separated...


I think it may be best to just have the outer ring be LOD-enabled and integrate both the inner and outer meshes into one.


EDIT: After investigating some myself, it may not be possible to automatically generate a LOD mesh with separate textures from the main LOD texture file.


However...  I am thinking... it may be possible to manually splice them in.  I am looking at Whiterun's Gildergreen circle in the LOD files, and I suddenly got the idea... put in a tree LOD mesh directly into the file and then save it.  Worth a 'speriment...


Or would it auto-generate a merged LOD texture in the process?


Also, it turns out you don't even need to change their file type extensions, you just need to associate them with NIFSkope, and it'll figure it out from there.


Also, have you revealed this resource to the mod community at large?

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Some WIPpy screenshots of the Temple of Miraak LOD mesh...


First, a screenshot of the original I am using as a guide: 



Next, the LOD WIP:



It weighs in at 6000 Tris at that point, and that's before I start cutting out the broken crumbled bits.  First, I need to UVW the one pie piece I've cloned all that from though.


Think I could cull some more from the arches and towers?


EDIT: Aaaand I just noticed I have too many weird inner spike thingys.

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This mesh is absolutely awesome ! :) You may be right in your approach to splice a custom LOD texture in the existing one, that would only require a proper UV remapping. But, honestly, I don't know if .bto files can be UV-edited in the same way as 'usual' meshes because Nifskope (that's the only tool I really know how to manage) doesn't render them textured.


As summer holidays are over for me, I've gone back to my job and I won't be able to invest much more time on this issue. I'll  catch an eye on it this week-end, though.


Also, have you revealed this resource to the mod community at large?


No, not yet. I may do it soon, and Nexus would be the best and most accessible place to do it. But, honestly, I doubt this can be very useful to the community. 'Worthy' mods with large worldspaces that require reliable LOD are very few, and they use their own brand new worldspaces (Falskaar, Wyrmstooth, probably Issgard soon, I suppose...). So, authors always incorporate their full generated LOD in their releases. Who (at the exception of the USKP & bros' team) may consider injecting new objects in the already existing LOD and release .bto files only for the affected LOD cells ? ...


LOD is not at all my speciality. I spent time trying to understand the rules that govern the .bto & .btr files generation and naming conventions exclusively for Unofficial Patches purpose, as nobody seemed enthusiast to look for it. Even crossing 'intuitions' (with a touch of luck too, I have to admit it) and Worm's existing ressources for the original game cells took me about 12-14 hours. I do not fear thankless and repulsive tasks (it wasn't a sweet piece of cake, not at all..) but I doubt I'll be able to help much more...


LOD in Skyrim, however, has its own specs. I didn't investigate much but, FWIW, SjoertJansen, the author of Skyfalls and Skymills - Animated distant waterfalls and windmills has interesting comments on the topic. First, if he's right, animated LOD objects do already exist in vanilla Skyrim and were introduced with Dawnguard. Rock fragments floating and rotating on top of Soul cairn towers can be seen from distance. The forgotten vale waterfalls seem to be composed of 2 layers : the hi-poly and fully animated one, and the LOD one 'embedded' within, then one switches with the other when approaching.

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I am seeing options for texture compiling of some manner int he LOD generation window for the CK.  Also, the final LOD texture is separate from the textures that individual meshes are made from, much like the LOD meshes.  We'll see what happens...

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Am I allowed to reveal the existence of your LOD gridmaps to SjoertJansen, Nico?  I am going to PM him, partly to inform him that there may be a clash with his Solstheim LOD texture in SkyFalls, and partly to ask him just how the heck to go about baking new LOD meshes/textures.


Also, a question to Arthmoor: Would this qualify as UDBP-worthy?  Is it a valid omission bug?


And lastly, a textured LOD mesh:



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...Nevermind, Nico.  Looking at the proverbial voodoo rituals you had to do in order to bake new terrain, I decided to just take a wild jump and splice the mesh directly into the BTOs.


Not sure if you have access to the USKP file uploads, but check it out here: http://www.afkmods.com/index.php?/files/file/853-temple-of-miraak-lod-splice/

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Am I allowed to reveal the existence of your LOD gridmaps to SjoertJansen, Nico?

Yes, of course. I don't claim any ownership or property on any part of my work. No authorization required at all. Absolutely no restrictions, even if it would be kind to mention me. Hey, this forum is public, isn't it ? :)


I will however make 2 additional maps before releasing this ressources on Nexus. They will just display the true game cells. Something similar to the one made by Worm, but scaled to the same size as my maps, and with Solstheim addition.


Anyone interested in the photoshop .psd source files ? Only 1 background for each map, with each grid in its own layer.

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Also, a question to Arthmoor: Would this qualify as UDBP-worthy?  Is it a valid omission bug?

I cannot express in Arthmoor's place. A different trick was used and implemented for the Azura's statue, but it was a long time ago, when Kivan was the only conductor in charge of the USKP... (btw, any news from him ? :unsure: ) Not a bug IMO, but still a very needed improvement.


Unfortunately, as a simple member I don't have access to the files hosted here. If you can provide a mirror link, or if an admin can make an exception on the simple members permissions/restrictions...


And, btw, I'm not a specialist about LOD generation, but I don't clearly understand the way you handle it. I personally never tried it myself but Hana has already made an attempt here (FR_dZastrX said interesting things), the basic tutorial is available here, and if I understand right then the .bto and .btr files, plus the new LOD textures (worldspace.objects.dds and worldspace.objects_n.dds) should be generated by the CK.


New worldspaces creators may have much more knowledge on the issue. I'm thinking about Wyrmstooth, Falskaar and Issgard creators.

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  • 3 weeks later...
  • 10 months later...

I have my own idea : ENBSeries forum is mainly populated by elitist modders nearly exclusively focused on graphical and post-processing improvements. Sheson points out that she doesn't want her tool to be uploaded or redistributed elsewhere. Well, FWIW, I think she wants to avoid at all cost the kind of trolls, noobs and disrespectful people you can find on Nexus or SW... :peer:  IMO that makes sense, and it's not the first time a talented modder chooses a 'quiet' place to work. Look at this topic about K-ENB. Kyokushinoyama (its author, and he's french !  :bunny: ) deliberatly abandoned Nexus to work among 'smart' people. And if you look at his screenshots, you'll understand that he is someone very, very, very requested.


Well, back to our topic. The bad thing is... probably ENB users don't care much about LOD... :shrug:

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nah, that's just the state of Skyrim modding. there aren't enough high skilled modders around for the top level awesome stuff (mind you, i'm not complaining. myself, i can't even script).

lots of great tools are being developed and barelly put to good use.

LODGen, DynDOLOD, HDT (if it's not about T&A. i'd have thought we'd have havok cloaks by now. nope!), character behaviors enhanced, new skill trees (i saw this in a thread once, it's fallen to oblivion, even i can't find it any more).

This was already apparent by the time DB came out. People were furious about not getting werebears, dragon riding and spears. but does that mean that the release of such with DB would have inspired alot of mods? no! ok, the spears were a joke. but still, with the knowledge hidden in some threads by now, those would be possible. i guess the need for them wasn't that high after all. or the required skills too high.


we can just be glad SKSE and MCM took off the ground (at least i do. a third of my load order offers MCMs :-D)

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So what exactly do these LOD scrips (do I understand it right that both the thing in TES5Edit and Sheson's are scripts of some sort?) do? The automatically generate new LOD meshes somehow? I thought meshes have to be manually created in an editor?

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I only made a tiny test but if I understand right, it's an esp that requires SKSE. It uses datas you have to previously generate using TES5Edit and the tools mentioned. These datas are directly relying on your active mods list and their load order. So, each time you add/remove a mod supposed to modify LOD (any house/buildings mods or just mods altering/adding statics in worldspaces) you have to redo the TES5Edit-side process.


Ingame, LOD will then appear dynamically according to what is supposed to really be 'active' in worldspaces. As Sheson said, a good example would be the 3 manors from Hearthfire DLC (and if someone makes low-poly versions of the new buidings) :

-At start : no manor ---> no manor LOD

-Slightly later : you build the base house ---> DynDOLOD dynamically applies the corresponding LOD, which you can now see ingame from distance. (No LOD at all in vanilla game)

-Slightly later : you build the armory wing ---> DynDOLOD dynamically applies the corresponding LOD, which you can now see ingame from distance. (No LOD at all in vanilla game)

-Slightly later : you build the library tower wing ---> DynDOLOD dynamically applies the corresponding LOD, which you can now see ingame from distance. (No LOD at all in vanilla game)


And all this dynamically, in the same playthrough, with no need to regenerate LOD manually in the CK at each stage !


Other example : Cities affected by the Civil War (Whiterun, Solitude, Windhelm). Ok, actually LOD for these cities is generic, poorly designed and unique. But let's say you want to make a mod whose LOD reflects the actual cities state. Depending on the civil war state, some buildings may be destroyed, and so the LOD should reflect this... Use DynDOLOD !


DynDOLOD enables these visual features dynamically, and without having to redo each time the long and boring objects LOD generation process in the CK (which however 'builds' solid meshes with the .bto file extension that are thus displayed ingame). And believe me : this process is an atrocious voodoo ritual requiring the use of external tools, the extraction of numerous specific objects meshes and textures, their placement in very specific folders, their conversion to .tga files, various CK crashes and atlas generation... :facepalm:

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