Delete all Precombine/Previs in mod

[cypher2012]

Is there a way in either creation kit or fo4edit to quickly delete ALL pre combine and previs data?

 

I have a mod that spans across many cells. I mucked about with the generate pre-vis. I want to delete all the data. I would like it so that afterwards, those cells that are otherwise not effected by my mod, are no longer marked as edited in creation kit.

 

I think I can safely wipe any edits to ALL cells where I have not placed a static or anim static object. If that helps.

[cypher2012]

Is it safe for me to go through everything under 'World spaces' and just delete all records that don't have 'Placed object' or navmesh (I've done some nav meshing which I want to keep)?

[VIitS]

You'll need to use FO4Edit (generic name is xEdit), the CK doesn't like letting you remove dirty edits , or really do much at all with previs/precombineds outside of generating them.

 

If you want to remove "dirty" edits (records you touched in the CK but either made no actual edits to or undid any edits you made), any record that has a green background in the tree (left side) and doesn't have any sub-records (i.e. don't remove Worldspace just because it is green :tongue:) can be safely removed, as it has no changes compared to the vanilla version of it. The quick way to do this is:

1) Right Click on the left side -> Apply Filter for Cleaning

2) Right click on your mod -> Remove "Identical to Master" Records (also known as ITMs)

 

If you didn't intend to move or delete anything, just add, then you can also delete any placed object references that have a yellow background, as that indicates that it is an edited record. A white background means it is the only instance of that record, so any newly added record in your plugin would have a white background. If you see a red background, that means two plugins have edited that record°, so same applies as with yellow records.

 

If you purposefully moved (or otherwise edited) some things and accidentally moved others (without noticing and undoing the edit, which would result in an ITM), you have to manually go through each of those edited (yellow or red) records and see if it was a purposeful change. Having both xEdit and the CK open at the same time (with xEdit opened after saving your changes in the CK, otherwise your changes won't be reflected in xEdit°°) is good for this, as xEdit will show the changed records and it's often easier to tell if you meant to change it when looking at it visually.

 

°when editing your mod in xEdit, you should only have your plugin and any required masters, so when cleaning your mod this should only happen if your mod has a DLC as a master, and are editing a record that is in the base game and also edited by the DLC.

°°A bit of warning: if you have a plugin open in xEdit when trying to save it in the CK (and vice versa), it won't let you save any changes made. You also won't be able to save (in xEdit or the CK) if you have the game running with the mod enabled

 

Beyond those (detailed info on previs/precombineds, and the editing thereof):

 

 

In xEdit, you can previs/precombined data is all stored in the CELL record (the one just under sub-blocks, whether it's under the "Worldspace" or "Cell" main category) . The relevant fields are VISI, RVIS, PCMB, XPRI, and XCRI.

1) VISI and PCMB are "timestamps", which tell the game when Previs (VISI) and Precombineds (PCMB) were generated for that cell. If you want the game to use your new previs/precombineds, those fields are essential*

2) You have to be careful with RVIS, as it tells the game which .usd file to use (that's the Previs file). Previs is generated in a 3x3 cell square, so if you want to change the previs in one cell, it will change that value for the surrounding cells. For this reason, if you want to minimize the number of affected cells (and prevent possible graphical glitches), you want to figure out which cell was used to generate the previs for the cell you are editing, and have the CK centered on that cell while generating your previs. That's what is stored in the RVIS field, so ideally you'd want to look at your mod in xEdit after making your edits and before generating previs. If you generate previs centered on a different cell, your new previs square will intersect with other squares, and so might cause some weirdness in those areas**. If you do this, the RVIS field should be the same as vanilla (i.e. green background for the field).

3) XPRI is generated when you make the previs, but does not list everything that was used to make the previs. Not really sure what determines whether or not something will be listed there, but if it's different than vanilla it's likely the previs will be different for that cell (though lack of changes doesn't guarantee that previs is the same)

4) XCRI is the list of every precombined mesh the cell contains, and the placed references that are part of them (note, the references count is doubled due to a quirk in how the game determines that value). If this field is green, you have made no changes to the precombineds at all, and you can safely delete any precombined meshes generated for that cell.

 

Once you have determined which edits were purposeful, you'll want to delete any unneeded uvd and nif files.

-For the .uvd files, they are saved in your Data\Vis folder and the name of the file is the FormID for the Cell used to generate it. You'll have to figure out which ones are used by the cells you edited (by looking at the RVIS fields). If you decide to remake the Previs so it matches the vanilla grid, I suggest just deleting them and starting fresh, in which case you'll only have uvd files you want to keep (if you have a mod that regenerated previs installed, and they didn't pack the files, you'll want to make sure to reinstall that mod after you are done).

-For the Precombineds, I recommend this wonderful xEdit script that zilav made. It can be used to automatically delete any precombined mesh (the nif files) that are unchanged from the vanilla ones, which will make your mod much smaller (if you made new precombineds, the way you worded things makes it sound like you just made new previs).

 

*Otherwise Bethesda's automated system will disable precombineds/previs in those cells if you made any changes to a record that was used as part of a precombined mesh, which is indicated in xEdit as [Placed Object]. If a cell doesn't contain any records with the brackets, it doesn't need new precombined/previs data unless you are adding new things to the previs/precombineds (and the game won't disable those systems in that cell without you manually editing the cell record in question)

 

**Not 100% certain on this, I've mainly been messing around with interior cells as part of my work on Scrap Everything, but I remember someone who figured something out related to ensuring your grid matches the vanilla one

 

 

 

If you want more info on precombineds/previs, this thread has just about every bit of info we (i.e. modders) have learned about the systems. If you want to just make a cell not use precombineds/previs, this script is great for that. DO NOT USE IT FOR INTERIOR CELLS. For an explanation on why, check the thread I linked.