The mesh itself hard codes paths to both materials and to texture files. The materials files are pointers, references that path or map to which textures should be used. The texture files are just that, they are the skin or skin and underwear combined. There are three parts to a body changing, the texture files, the material files and the meshes. But when i'm installing Body texture mods, i can't see any difference.

A while ago i deleted all my mods i had downloaded from the nexus mod manager, because my computer ran out of memory, so i deleted every mod for Fallout 4.

When i take the clothes off my character, she still has underwear on. I have tried to download different body texture mods (Not at the same time) but i don't see any changes.