Mod:Creation Kit/Actor/Dark Face Bug

The dark face bug, gray face bug or black face bug is a bug that happens to actors when their appearance is edited by the Creation Kit. If a new NPC is created or the face of an existing one is edited, then the bug is introduced into the mod. The actor with the new face will have a darker or grayer skin color on the face and head than on the rest of the body. There will be a sharp neck seam line between the two colors of skin.

Additional Causes
Aka *.dds vs. *.DDS. Fallout 4 requires the uppercase formatting.
 * Texture format mismatch

Common bug among those using the HD-DLC content and also Mod based face textures.
 * Texture Size mismatch
 * Standard Fallout 4 the specular texture must be BC5 512x512.
 * HD-DLC Fallout 4 the specular texture must be BC5 1024x1024

Fallout 4 requires the following formats.
 * Texture Format mismatch
 * Defused     (*d.DDS) to be BC1 without Transparency, and with Mipmaps.
 * Normal Map  (*n.DDS) to be BC5 with Mipmaps.
 * Specular Map (*s.DDS) to be BC5 with Mipmaps.

Workaround
This procedure can be used to solve the problem (tested on Creation Kit 1.9.32.0):


 * Select all the actors added by the mod or that have faces edited by the mod, in the Object Window under Actors -> Actor (see note, below).


 * Press CTRL + F4; you will be prompted to export the face gen data. This process may take some time depending on the number of actors you have selected. When it is finished, it will display a dialog window stating "Done."

The mod will now have meshes (.nif files) and textures (.dds files) associated with it that will need to be packaged and uploaded along with the .esp file. Failure to do so will mean that all players who download the mod will have the dark face bug when they use it, even though the problem no longer occurs on the computer the mod was built on.

The mesh and texture files will be in your Data folder:


 * Example 1: new NPC, ID 000012c4, added by a mod (ExampleMod.esp):
 * ...\Fallout 4\Data\Textures\actors\character\FaceCustomization\ExampleMod.esp\000012C4.dds
 * ...\Fallout 4\Data\Meshes\actors\character\FaceGenData\FaceGeom\ExampleMod.esp\000012C4.nif


 * Example 2: Vanilla NPC, ID 000918e2 (Fallout4.esp), edited by a mod:
 * ...\Fallout 4\Data\Textures\actors\character\FaceCustomization\Fallout4.esm\000918e2.dds
 * ...\Fallout 4\Data\Meshes\actors\character\FaceGenData\FaceGeom\Fallout4.esm\000918e2.nif

Some .tga texture files are also generated. Apparently, these aren't needed by the game and don't need to be uploaded with the .dds files.

Conversion
Textures *.dds and *.tga files are exported uncompressed and must be processed via Eltric which can be found under the Tools folder in your Fallout 4 directory. ...\Fallout 4\Tools\Elrich.exe

Texture Format as follows
 * d_dds - BC1 (1024 for both SD and HD-DLC)
 * n_dds - BC1 (1024 for both SD and HD-DLC; Yes, BC1 is the correct format)
 * s_dds - BC1 (512 for SD and 1024 for the HD-DLC)

More Information
Bethesda Tutorial - Creating an Actor.

Creation Kit NPC Facial Textures Help