Transmission

glTF extension: KHR_materials_transmission
glTF properties: transmissionFactor · transmissionTexture

Transmission controls how much light passes through a surface (e.g. glass, thin plastic). Requires KHR_materials_transmission to be enabled in the export options.

Shader	Attribute	Notes
`standardSurface`, `aiStandardSurface`	`transmission`
`openPBRSurface`	`transmissionWeight`
`StingrayPBS`	not supported	—

Factor only

Set the transmission attribute directly on the shader.

standardSurface, aiStandardSurface: set transmission.
openPBRSurface: set transmissionWeight.

Exports as transmissionFactor.

Texture only

Color space: Raw

standardSurface · aiStandardSurface:
  aiImage.outColorR  →  shader.transmission
  file.outColorR     →  shader.transmission

openPBRSurface:
  aiImage.outColorR  →  shader.transmissionWeight
  file.outColorR     →  shader.transmissionWeight

Exports as transmissionTexture. glTF reads classic transmission from the red channel.

Note

Use outColorR, not outAlpha. If your graph drives the same Maya attribute via outAlpha, that belongs to the diffuse transmission workflow (see the Diffuse Transmission page).

Factor + texture

glTF computes: transmissionFactor × transmissionTexture

Connect the texture outColorR → multiplyDivide.input1X.
Set the transmission multiplier in multiplyDivide.input2X.
Connect multiplyDivide.outputX → shader.transmission (or transmissionWeight).

standardSurface · aiStandardSurface:
  texture.outColorR  →  multiplyDivide.input1X  →  shader.transmission

openPBRSurface:
  texture.outColorR  →  multiplyDivide.input1X  →  shader.transmissionWeight

The multiplier exports as transmissionFactor.

UV transform

file nodes: set repeat, wrap, mirror, offset, and rotation on the connected place2dTexture.
aiImage nodes: wrap, scale, and offset export natively; rotation requires a place2dTexture.

UV set: assign via Maya's UV Set Editor or UV Linking — see UV Set Selection for node-type differences.

Notes

Transmission is a non-color workflow. Always use Raw color space.
Use grayscale transmission maps; glTF reads the value from the red channel.
standardSurface / aiStandardSurface use transmission; openPBRSurface uses transmissionWeight.
StingrayPBS does not export KHR_materials_transmission.
This page covers classic (specular/refractive) transmission only. Diffuse transmission is documented separately.