Modding:How To Find A Virtual Texture

A virtual texture is essentially a digital box that BG3 uses to store textures in so they load quicker. This is good for the game's performance, but not so good if you want to extract and edit them. So here is how to extract them.

This tutorial requires Modder's Multitool, LSLib v19 and a knowledge of how to find things with the multitool.

How to find the mesh

First thing you need to find the item is its name -the exact item name it has. For example, 'The Deathstalker Mantle'.

Put the name(or the NPC's name, to lead you to their CharacterVisuals entry) in the modder's multitool index search. This should lead you to its entry in the english.loca file.

Take the handle (a handle is h[string of numbers], similar to an UIID) and search that.

This should lead you to the roottemplate of the item. (if it doesnt have one in the roottemplate, it's in the parenttemplate's file instead)

You can then find its mesh mapkey. Search that and you should find the meshes lsx entry.(You can skip the above if you know the mesh name.)

Finding it with the mesh name

Search the mesh name in the search index.

You may need to append it with HUM_M_ instead of whatever race you are looking for, as most of the universal gtex are under HUM M meshes. The same applies with HUM F and female specific meshes. Some meshes also share textures with other versions of the mesh, so you may need to remove the _a or _broken (for example) appendage if you aren't getting any matches.

We like 'HUM_M_ARM_Bandit_C_Body' so we search this in the multitool.

It has an entry in Shared\Public\Shared\Content\Assets\Characters\Humans\[PAK]_Male_Armor\_merged.lsf' so we click convert & open' for that.

We CTRL+F HUM_M_ARM_Bandit_C_Body and find a mesh entry for it.

  <node id="Resource">

                    <attribute id="AttachBone" type="FixedString" value="" />
                   <attribute id="AttachmentSkeletonResource" type="FixedString" value="" />
                   <attribute id="BlueprintInstanceResourceID" type="FixedString" value="" />
                   <attribute id="BoundsMax" type="fvec3" value="0.5363549 1.713599 0.176041" />
                    <attribute id="BoundsMin" type="fvec3" value="-0.5405712 0.6668076 -0.219203" />
                   <attribute id="ClothColliderResourceID" type="FixedString" value="" /> 
                   <attribute id="HairPresetResourceId" type="FixedString" value="" />
                   <attribute id="HairType" type="uint8" value="0" />
                   <attribute id="ID" type="FixedString" value="8e7bcc4a-2b65-d704-1cf0-a1a3bc8b8bd3" /> 
                   <attribute id="MaterialType" type="uint8" value="44" />
                  <attribute id="Name" type="LSString" value="HUM_M_ARM_Bandit_C_Body" /> (bolded for importance!)

We scroll down and find

       <attribute id="LOD" type="uint8" value="0" />
    <attribute id="MaterialID" type="FixedString" value="57a6fd6e-c00d-60eb-5e52-31560b95332b" />
        <attribute id="ObjectID" type="FixedString" value="HUM_M_ARM_Bandit_C_Body.HUM_M_ARM_Bandit_C_Body_Mesh.0" />
           </node>

This material ID is what we need. We scroll back up to the start of the file and search that.

We find

                <node id="Resource">
                   <attribute id="DiffusionProfileUUID" type="FixedString" value="" />
                   <attribute id="ID" type="FixedString" value="57a6fd6e-c00d-60eb-5e52-31560b95332b" />
                   <attribute id="MaterialType" type="uint8" value="22" />
                 <attribute id="Name" type="LSString" value="HUM_M_ARM_Bandit_A_Body" />

At the end of the material we find

            <node id="VirtualTextureParameters">                    
            <attribute id="Enabled" type="bool" value="True" />
            <attribute id="ExportAsPreset" type="bool" value="True" />
            <attribute id="GroupName" type="FixedString" value="Texture Map" />
         <attribute id="ID" type="FixedString" value="d53fa1a1-aa8e-2564-1077-42f6c36086c5" />
            <attribute id="Index" type="int32" value="0" />
            <attribute id="ParameterName" type="FixedString" value="virtualtexture" />
              </node>

So we search d53fa1a1-aa8e-2564-1077-42f6c36086c5. Luckily for us it is in the same file. (If it isn't you may need to search the multitool with it.)

<node id="Resource">

                   <attribute id="GTexFileName" type="FixedString" value="b049a62336641c449903f6ec8b4dae67" /> 
                   <attribute id="ID" type="FixedString" value="d53fa1a1-aa8e-2564-1077-42f6c36086c5" />
                   <attribute id="Localized" type="bool" value="False" />
                   <attribute id="Name" type="LSString" value="HUM_M_ARM_Bandit_A_Body" />
                   <attribute id="Prefetch" type="bool" value="False" />
                   <attribute id="PrefetchMipLevel" type="int8" value="-1" />
                   <attribute id="ReferencedColorSpaces" type="uint32" value="6" />
                   <attribute id="SourceFile" type="LSString" value="" />
                    <attribute id="VirtualTextureLayerConfig" type="uint32" value="3" />
                   <attribute id="_OriginalFileVersion_" type="int64" value="144115205255725056" />
               </node>

b049a62336641c449903f6ec8b4dae67 is the correct string. Now you can extract it from the virtual textures.

And we do see that it shares a texture with the other bandit models- it is the part under the armour. We will need to go back and extract the armour and accessories seperately by looking at the materials under the different mesh chunks listed in the mesh entry.

Lslib

Lslib v19 lets you unpack just specific gtp files via the gtex name.

Alternately you can just unpack all the VT into one folder and just search with Windows Search, but this is extremely file heavy and not recommended.

Remember Mipmaps

The extracting process strips the virtual textures of their mipmaps! Even if you are not editing some maps, you need to import them into GIMP(or any similar program) and resave with mipmaps to generate new ones if you are including them with your mod. See here for save settings.