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05.TextureSetup

Purpose

In this step, you'll understand the texture structure of synthetic hair and the role of each map. Hair's shine, directionality, and transparency are all expressed through two textures: a DIRO map and a Flow map. These maps are applied to the Hair/Scalp slots using the same master material.

Texture Composition Summary

division Example file name Format sRGB explanation
DIRO map HairCard##_DIR0.tga TGA OFF Core texture with Depth/ID/Root/Opacity packed into RGBA channels
Flow map HairCard##_Flow.png PNG OFF Used for anisotropic expression by controlling hair direction

DIRO Map (Depth / ID / Root / Opacity)

File rules: .tga , sRGB OFF , RGBA 4-channel use

channel name role
R Depth Hair card depth and shading information expression
G ID Identification channel for highlight distinction
Also used to express aged gray hair
B Root Hair root color and gradient starting point data
A Opacity Hair Card Cutout (Transparency) Information
Tip:

The quality of the DIRO map determines the overall texture of the hair. If the color contrast between textures is too strong, the edges can become noticeable, so it is recommended to use a smooth gradient for the Depth and Root values.

DIRO Map Example

DIRO Map Example
R Channel - Depth G Channel - ID B Channel - Root A Channel - Opacity
R Channel - Depth G Channel - ID B Channel - Root A Channel - Opacity

Flow Map (Directional Map)

File rules: .png , sRGB OFF

role explanation
Direction By controlling the light reflection direction of the hair card, highlights similar to the actual flow of light are expressed.
Anisotropy effect Defines the direction in which the gloss increases along the flow direction.
Applicable location Both Hair and Scalp are mapped based on the same UV1.
💡

Flow maps primarily represent the "texture" of hair cards.

Flow Map Example

Flow Map Example

Material Instance Configuration

slot Instance name Usage map explanation
Slot 0: HairCard MI_Hair DIRO + Flow For main hair card expression
Slot 1: Scalp MI_Hair_Scalp DIRO + Flow For scalp mesh (using the same master)
Slot 2: HairCard_LOD MI_Hair_LOD DIRO + Flow
  • Apply the same material as Slot0
    • If you need to be able to adjust the hair length
  • A version of Slot0's material with the alpha value removed
    • When hair length adjustment is not necessary
  • If hair length adjustment is not necessary, change the LOD Overwrite value to 1 when connecting the LOD version of the material for LOD2~4 as shown below.
LOD Overwrite

Representative parameter examples:

  • Tipcolor — Basic dye color
  • 2ndColor — Two-tone color
  • Highlight Color1~3 — Highlight Color
  • Specular, Roughness — light reflection/texture control

Things to check

item Things to check
Do both DIRO and Flow maps exist? Make sure the two textures are set up with the correct structure.
Are the TGA/PNG format and sRGB settings correct? Check format and detail options
Does the RGBA channel contain the correct information? Check the appropriate information values for R/G/B/A channels
Does the same master material apply to Hair/Scalp? Check the master material (Parents) of hair
Does the customizing UI respond normally when parameter values are changed? Verify that it is working as intended

Mistake-avoidance tips

situation cause How to solve
Hair texture output is awkward DIRO structural issues Check if the appropriate texture is applied to each channel
Check if sRGB is off
Check if the hair strands in the Opacity Map are too thick or too thin

Summary of this section

Checklist Whether completed
Understanding the DIRO map structure (R/G/B/A roles) ✅
Understanding how to apply flow maps ✅
Make sure to use the same master for both Hair and Scalp ✅
Check sRGB settings (OFF) ✅
Check the results by adjusting the parameters ✅

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