▫️Definitions

Understanding and leveraging RED4 shaders

We do not have official documentation from CDPR about how shaders are used by artists. Thus any 2d/3d artist is looking at hundreds of black-box shaders with unknown usage. This is extremely demotivating for anyone looking to bring new assets to life with REDengine. The following list of tables is an attempt to make life easier for artists by using the community to document commonly used shaders.

About the documentation

• The name and path of each shader will be documented by the header.

• Next we are using a table for each texture parameter with the exact name listed by CDPR in the w2mg file, how REDengine uses each specific RGBA channel, and the usable range of the channel if not 0-1/0-255.

• When applicable, vertex color properties will be listed underneath the texture table with a similar format.

• Scalar, vector, color, and other properties will follow with their own unique description table.

• An asterisk (*) is used to notate some degree of uncertainty, or need for more independent testing.

Shaders

skin

base/materials/skin.mt

Texture	Red	Green	Blue
Albedo	Color	Color	Color	?
SecondaryAlbedo	?	?	?	?
Normal	Normal	Normal	None	?
DetailNormal	Additive Normal	Additive Normal	None	?
Roughness	Roughness	None	MicroDetail mask (0.5-1)*	?
MicroDetail	Additive Normal	Additive Normal	None	?
TintColorMask	?	?	?	?
Detailmap_Stretch	Additive Normal	Additive Normal	None	?
Detailmap_Squash	Additive Normal	Additive Normal	None	?
EmmisiveMask	?	?	?	?
Bloodflow	?	?	?	?

Vertex Colors	Description
Red	Ambient Occlusion*
Green	Subsurface Scattering Mask
Blue	Improved Facial Lighting Mask

Properties	Description
SecondaryAlbedoInfluence	?
SecondaryAlbedoTintColorInfluence	?
DetailRoughnessBiasMin/Max	?
MicroDetailUVScale01/02	?
MicroDetailInfluence	Controls MicroDetail normal intensity
TintColor	?
TintScale	?
SkinProfile	?
EmissiveEV	?
CavityIntensity	?
BloodColor	?
DetailNormalInfluence	Controls DetailNormal normal intensity

Notes

• The DetailNormal texture contains generic normal details that are shared between most faces. This is not a tiling/procedural texture. The DetailNormalInfluence scalar parameter can be used to lower the intensity to simulate makeup or synthetic skin.\

• The MicroDetail texture contains a microblend tiling texture used to add procedural detail to the normal map. We believe the Roughness texture blue channel is used to mask parts of the face from exhibiting this detail, such as the lips, eyelids, and ears.

mesh_decal

base/materials/mesh_decal.mt

Texture	Red	Green	Blue	Alpha
DiffuseTexture	Color	Color	Color	Opacity Mask
SecondaryMask	?	?	?	?
NormalTexture	Normal	Normal	None	?
NormalAlphaTex	?	?	?	?
NormalsBlendingModeAlpha	?	?	?	?
RoughnessTexture	Roughness*	Roughness*	Roughness*	?
MetalnessTexture	Metalness*	Metalness*	Metalness*	?

Properties	Description
VertexOffsetFactor	?
DiffuseColor	Procedural Color
DiffuseAlpha	Alpha
UVOffsetX/Y	?
UVRotation	?
UVScaleX/Y	?
SecondaryMaskUVScale	?
SecondaryMaskUVInfluence	?
NormalAlpha	?
UseNormalAlphaTex	?
NormalsBlendingMode	?
RoughnessScale	?
RoughnessBias	?
MetalnessScale	?
MetalnessBias	?
AlphaMaskContrast	?
RoughnessMetalnessAlpha	?
AnimationSpeed	?
AnimationFramesWidth	?
AnimationFramesHeight	?
DepthThreshold	?

Notes

• DiffuseColor multiplies against the texture color to add procedural color