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The necessity of ITM records


tippisum

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Given the mechanism how the ESM/ESP records got overridden, adding an ITM (Identical To Master) record should not have any useful effect.
 
However, I did noticed that quite a few mods explicitly claimed that the ITM records were used INTENTIONALLY and should not get cleaned.

That made me wonder, what is the real technical reason behind the usage of ITM records?

 

I tried to make some guess.

1. The records that TES5Edit marked as "Identical" are not actually identical. Differences in unknown/not decoded fields lead to subtle behaviors in game.

2. The ITM records are intentionally added to "fight against" some known mods that do impolite modifications.

3. The ITM records are added to address issues related to middle-game mod installation/uninstallation/upgrading.

 

Is there anything else?

Or alternatively speaking, should those conditions always met, Will some ITM records still be necessary, and why?

a) A new game is always started after any mod got changed.

b) All mods are loaded in their optimal order, with all conflict issues resolved.

 

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i think 3 and b are wrong guesses, the others might hold some truth. but usually, whenever an author claims their ITMs are intentional, they usually are clueless.

the USKP needed to forward some ITM from skyrim.esm to overwrite wrong/unintentional changes from update.esm (or the DLC patches to overwrite errors in the DLCs to vanilla entries). those changes are done in a way that TES5edit does not flag them as ITMs. there is no confusion and no loot/edit error message. This is what an intentional ITM should look like, not those from lazy authors claiming everything in their esp is intentional. If there was an author claiming their ITM to be intentional, i have never seen them explain their intention (except in the case of USKP). go figure.

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Imagine you have a quest that critically relies on some vanilla marker in the world, even a small change to it's position will break your quest mod. So you copy that marker as ITM in your plugin to prevent possible interference from other mods loaded early. This is a made up example, but gives general idea when ITM records are necessary - you have some content that work only when certain data is in vanilla state. Mind you such cases are very rare and conflicts are usually solved by proper load order and compatibility patches.

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In general you're going to find that 99.99% of mod authors who claim "this ITM is intentional, don't touch it" have no idea what an ITM even is, let alone why they need it to stay put. Ask them to be specific and they can't. Those authors who CAN get specific about it also know how to prevent their intentional ITM from getting cleaned. Which, ironically, makes it not an ITM :P

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Thanks, everyone.

 

Sure I do not believe MOST (if not ANY) of the "intentional" ITM records are really necessary, provided that I did spend some time studying some internal of TESV engine.

I asked here for being certain and not missing some corner cases.

 

So let me be more clear about my question.

 

 

I would like to know, provided that those condition below always met.

a) Any changes to mods will be done BEFORE a new game is started. (i.e. no middle-game installation/upgrading)

b) Any conflict will be resolved MANUALLY with CK or xEdit.

 

Is it SAFE to treat ALL those ITM records unnecessary (and safe to clean) FOR CERTAIN? Is there any (even rare) corner case that indeed need ITM record to exist for correct functioning, according to your knowledge of the game engine and your modding experience? If there is, what is it (and why it is necessary, if possible)?

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"Any changes to mods will be done BEFORE a new game is started. (i.e. no middle-game installation/upgrading)"

Nope, you can freely add/remove/upgrade plugins in the middle of the game. The only problem are scripted mods, however most of them has MCM menu with deinitialization switch to stop all scripts for safe uninstallation, or instructions in description. If there are no instructions provided, then you can stay away from such mods to be safe or just never uninstall them when playing.

 

"Any conflict will be resolved MANUALLY with CK or xEdit."

You can almost always find compatibility paches for conflicted mods already made by other people for you. Or just do them yourself.

 

"Is it SAFE to treat ALL those ITM records unnecessary (and safe to clean) FOR CERTAIN"

Only mod authors should know that, but as Arthmoor said they don't have a clue themselves :facepalm:

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Or in laymans terms: there is no need for an itm, unless specifically designed to overwrite some conflict with another mod and purposfully refert a setting back to vanilla. If you do not have this conflict in your load order, the itm can savely be removed. You can also you leave it, it doesn't matter.

 

Now if you do have a conflict, you best ask the authors of said mods what their respective changes are for and what type of conflict resolution they suggest.

 

(correct me if i'm wrong but the times where tesxedit would falsely flag something as an itm, because the data type was not yet fully decrypted are over, right?)

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(correct me if i'm wrong but the times where tesxedit would falsely flag something as an itm, because the data type was not yet fully decrypted are over, right?)

Almost everything is fully decoded now. And even some values are supported that work but don't shown in CK.

xEdit never treats undecoded data as ITM, it is displayed as hex array that conflicts like any other normal value.

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A simplest example of this crops up while doing the tutorial mod when the mod changes the xyz fields of an object. But sometime later we decide to put the object back in its original position. The record of the object remains in the mod and is ITM.

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Bethesda's tutorial mod isn't the greatest example :P

 

Without going through the pain the CK has of trying to remove it using it's convoluted interface for it, generating an ITM is the only way they could "fix" the problem. In a case like that, the ITM would be entirely safe to clean out.

 

The corner cases where an ITM needs to remain in place are going to be so rare as to make the whole idea of worrying about them silly. This has pretty much been the case ever since Oblivion when even some major overhaul makers tried to tell people ITMs were critical to its operation but it turned out to be entirely false. Took YEARS to get past that in general and there's still some diehards who insist otherwise to this day.

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