Confused about BGSMs and Textures

[SteelRat1962]

So I'm trying to figure out how BGSMs work in relation to texture files.

 

My conundrum example:

 

In the CC, there are 6 objects called AdvertsPoster, 01-06. Each one seems to use the same BGSM, AdvertsPosters01.bgsm, but display different portions of the texture file AdvertsPosters01_d.dds, which has 6 distinct areas of the image intended to represent 6 different posters. How does that work using the same BGSM?? I would think that each object would use a variant of the BGSM with different U/V offsets, but that clearly isn't the case.

 

Can someone explain how this works and how I can gain control over which portion of the texture file is displayed?

 

Thanks!

[DieFeM]

It probably uses different U/V offsets in different BGSM files through material swaps that are applied at references or in base objects.

[niston]

Or the UV mapping of the models itself is different.

UV mapping can be sort of edited with NifSkope. It's very rudimentary, but it works.

[SteelRat1962]

It probably uses different U/V offsets in different BGSM files through material swaps that are applied at references or in base objects.

 

I didn't see a material swap on any of them.

 

I tried changing the UV offsets in the BGSM using Material Editor, but didn't see a change at all. Also tried in Nifskope, but also didn't see a change. Though I'm not very familiar with Nifskope, so I could have been totally off base.

 

How do I see if there is a reference that's changing the BGSM that's used?

[Zorkaz]

In Nifskope:

When you open the nif you can click on BSTrishape/BSLightingShaderProperty. That's where you'd find the reference for the .bgsm. (It can be empty though)

A folder below you'd find the textures.

[DiodeLadder]

I've looked at those .nif files, and just like niston said, the UVs themselves are different on 6 meshes. This method is better than having 6 different material files with UV offsets because one material file will add one draw call. Fewer material files loaded = better optimized scene.

 

So, if you are adding another texture set of 6 posters and want to see different parts, just pick the mesh with the UV in the right coordinates as a base.

[SteelRat1962]

So, if you are adding another texture set of 6 posters and want to see different parts, just pick the mesh with the UV in the right coordinates as a base.

 

That's what I've done in the past. I was just trying to understand what was happening.

 

Thanks all for the replies!

[DieFeM]

 

How do I see if there is a reference that's changing the BGSM that's used?

 

 

To find out "what uses what" in the CK you only need to right click on it and click on "Use Info".

So, you click on "Material Swap" in the left panel of the object window, it is located inside of the Miscellaneous.

Use the word "Adverts" as filter, and you see listed some material swaps, AdvertsPoster01_02Swap, AdvertsPoster01_03Swap, and so on.

If you check the "Use Info" on any of them, you will see a list of references using them.

You can double click on any of the references in this list to show it in the render window.

If you see the properties of the reference in the render window, one of the tabs is called "Extra", there's a dropdown menu named "Material Swap", which shows a list of the swaps that can be used on such reference.

 

[RoNin1971]

The BGSM & the UV mapping are 2 separate things.

 

The BGSM contains a link to what texture to use, not how the UV looks like, which depends on the model. This allows for swapping the texture (material) for something else, which will fit the same UV.

 

This is done in many cases. Most meshes use multiple materials & materials are used on multiple meshes.

 

so, nothing strange going on here.

 

edit:

Best example: Look at all those trees. There is only 1 maple tree texture (for the branches) & 1 BGSM, for ALL maple trees. They all do have different UV's, mapping different parts from the texture. Creating all this 'variety' you see in the game.

Edited September 17, 2022 by RoNin1971

[DieFeM]

The BGSM & the UV mapping are 2 separate things.

 

The BGSM contains a link to what texture to use, not how the UV looks like, which depends on the model. This allows for swapping the texture (material) for something else, which will fit the same UV.

 

 

Actually, you can change the UV offset and scale in the materials. And that's what make possible using the material swaps to use multiple offsets of the texture from the material on the model.