Converting FO4 normal maps

[Deleted137276User]

The normal maps in FO4 appear to contain additional data encoded into some channels. Does anyone know what this additional data is? Opacity map, specular, etc? Is there a format specification or information anywhere?

 

Edit:

 

 

_d = diffuse (obviously)

_s = specular (various channels represent gloss/metallic)

_n = normal map

_f = ?? it has data in the red and blue channels ??

 

So -- the Normal maps are all green, so either the channels are compressed into r/g - or something else is going on. If anyone knows more about the normals, or what the other file types are, that would be helpful.

Edited January 24, 2017 by Guest

[Deleted137276User]

_n (Normal maps) (edit) Another site claims they are inverted tangent maps. Needs more investigation.

_s (Specular) actually appears to be a metallic map. R= Metallic, G=Gloss (roughness) B/A appear to be unused.

 

_f -- still no idea, but I can deal with the rest.

Edited January 24, 2017 by Guest

[TrickyVein]

Normal maps are compressed using BC5 and only use two channels. The same for specular maps. Diffuse textures may or may not have alpha merged into RGB channels.

 

Out of curiosity, why do you think normals contain more information than they should? Here are the common compression settings for textures in the game:

 

BC1 - for textures with 1-bit alpha or no alpha

BC3 - for textures with 8-bit alpha

BC5 - for two-component textures (smooth/spec and normal maps)

BC7 - for textures with or without 8-bit alpha that you want very good compression on. NOTE: Your computer will chug heavily or freeze for up to a few minutes when using this as it calculates the best compression.

Other texture slots in materials can be glow maps, environment maps, "masks, or gradients.

As far as converting normal maps, the green channel is inverted in Fallout 4 compared to, well it seems most everything else.

Edited January 24, 2017 by TrickyVein

[Deleted137276User]

Perfect - thank you. The reason I thought it contained more data was that a different tool that I used compressed the Blue vector out (you had to reconstruct it based on the normal being a unit vector), and then packed other data into B/A. I didn't even realize there was a specific 2 channel DXT format. This makes my conversion much easier.

 

There's a lot of misinformation everywhere, much appreciate the info.

 

What I'm attempting to do is convert some 3rd party FO4 mesh and textures to "generic" format, for use in Unity (I have permission). We can get the meshes over to .obj with nifskope and they retain the UV (and don't care about bone bindings, since we have to rerig them anyway). The only hold up was the normal map.

Edited January 25, 2017 by Guest