Still confused about previs and precombined

[Zorkaz]

In the CK are the following options

 

 

Visibility / Generate Visibility for Current Cell

Visibility / Generate Precombined Visibilty for Current Cell

World / Precombine Geometry for Current Cell

 

 

What does it do exactly, where is the difference? I'm especially confused about the two types of generating precombined meshes

[Pelgar]

I can't explain all of the in and outs of the different precombine and visibility choices in the CK. I have uploaded a couple of rich text docs to my Google Drive, one for doing precombines in interior cells and one for exterior cells. Each .rtf has links at the top to tutorials I followed to get the information. I've used these several times myself and been happy with the results.

 

Interior Precombines

 

Exterior Precombines

[VIitS]

Another good resource for understanding the systems is this thread: https://forums.nexusmods.com/index.php?/topic/5522717-fallout-4-optimization-and-performance-systems-explained/ if you want to go more in-depth, but if you just want to generate precombineds for a mod then Pelgar's guides look pretty good.

A lot of the info is in the OP, but some stuff (especially in regards to generating shared-geometry precombineds like the base game+DLC use*) are spread in later posts.

One thing I will note about previs: while I think the current version of the CK does this automatically, you want to ensure that previs in exterior cells is generated with the same central cell. Previs is done in 3x3 cell grids, and if the grid for your cells is out of alignment with the rest of the worldspace, that will cause significant object flickering issues. You can check by making sure the RVIS subrecord is the same for your plugin as it is for the source (Fallout4.esm or DLC if one of those worldspaces). That value is hidden in the CK so you would need to use FO4Edit to check it.

I know that older versions of the CK didn't necessarily center previs properly if you didn't have the right cell selected (or maybe loaded) when generating, so it is worth checking to make sure that the current CK doesn't have that issue.

*the main differences with Shared-geometry precombineds are that they use .cdx/.csg files, are much smaller (often on the order of 1/5 to 1/10) the size of the ones generated from within the CK, and also seem to be somewhat finicky and esily broken (such as by changing the name). They require an edit to the Creationkit.exe, and the filename can't have spaces, which is why the inability to change the filename after matters.