Resource:Masking textures for rusty armors with cubemaps for Fallout 4

Masking textures for rusty armors with cube maps for Fallout 4 is a resource guide from a feature discovered by Satan Jr. and transcribed by Wanaming0.

Info
Cubemaps are used in BGSM material files to represent represent the reflections of the environment around an object. They are often used to give an extra layer of color in the reflections as Fallout 4 specular maps do not have specular color.

Usually, when applying cubemaps to armors, you separate the parts you want to have different or plain cubemaps from the parts you want metallic cubemaps on, but sometimes meshes will still have parts you can't separate in a practical way, such as rust marks, paint, or other non-metallic bits.

.BGSM files, or Bethesda Games Shader Material files, are able to use either a cube map or a glow map, but not both at the same time. This is sort of a feature for material files that use cube maps, as the slot for the Glow map will instead work as a **mask slot**. You can see an example of this use in the vanilla Machete. You do not need to enable the glowmap flag in the material file in order for this to work, but doing so won't change anything as the.

To make a mask, you need a black-and-white texture. The white will represent the parts with cube map, the black will be the parts without. It supports shades of gray in-between as well for different amounts of cube map shine/tone.

If you lack a proper mask due to not being the original author of the textures, you can make a makeshift mask by opening the diffuse in photoshop, applying a black-and-white filter (upping the parts that you do not want to shine, i.e. if it's rust, then reds and yellows cranked to the max), and then one or two contrast filters increasing the contrast greatly. Finally, you need an invert filter, so the white parts are the parts you want to shine. Darken whatever you don't want to shine and save either as BC1, BC3 or BC7, depending on the level of quality and size you want.

License
This tutorial is under Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)

Credits

 * Satan Jr. for discovering this and sharing it with us.
 * Wanaming0 for transcribing and testing this.