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glTF Material

The new glTF Material uses a shading model that gives an accurate representation of what your asset will look like once published to glTF.

  • Material Editor > General > glTF Material
    • Note: The material appears in the Material/Map Browser only if the active renderer supports it.
The glTF Material is a modern material with controls focused on a glTF-based workflow.
Note: In Bitmap Texture, the Tiling, Offset and W_Angle properties are exported using the KHR_texture_transform extension if Offsets or W Angle are non-zero or Tiling is none to one.

The 3ds Max System Units influences how the glTF material is previewed in the Max viewport. When using the glTF Material, scaling the affected attributes is required to ensure that the 3ds Max render/viewport preview matches the glTF viewer being exported to.

Interface

glTF Material Parameters

Base Color Map

Metalness=0.0 and Base Color=yellow, grey and red respectively

Maps added to the Base Color Map Parameter can be considered the diffuse color for non-metals. For metals, it is the color of the metal itself.
Alpha Map
Defines how the alpha value is interpreted.
Note: Unlike other materials in 3ds Max, the alpha is derived from the RGB Value of the Alpha input map and not the Bitmap's Alpha channel.
Metalness Map

Metalness=0.0, 0.5 and 1 respectively

Values range from 0.0 for non-metal to 1.0 for fully reflective metal.
Roughness Map
When applied, a higher roughness yields a blurrier material, while a lower roughness yields a more mirror-like material.
Note: The default Roughness value is 0.0. When a Roughness Map is added, the Roughness value is automatically set to 1.0.
Normal Map
A tangent space normal map.
Occlusion (AO)
The Ambient Occlusion is a greyscale map that darkens the diffuse color.
Emission Map

Emission=black, red and green respectively

This map controls the color and intensity of light being emitted by the material (self-illumination).
Clearcoat Map

Clearcoat=0.0, 0.5 and 1 respectively

This map defines a clear coating that can be layered on top of the material.
Clearcoat Roughness Map

Clearcoat=1 and Clearcoat Roughness=0.0, 0.5 and 1 respectively

This map defines a Clearcoat Roughness that can be layered on top of the material.
Clearcoat Normal Map
This map alters the clear coat appearance based on a normal map input.
Sheen Color Map

Sheen Roughness=0.1 and Sheen Color=red, green and blue respectively

This map drives the color of the sheen component of the material. Sheen simulates the back-scattering of velvet-like materials.
Sheen Roughness Map

Sheen Color=red and Sheen Roughness=0.0, 0.5 and 1 respectively

This map determines how much back-scattering is present. A small roughness results in a sharp specular response around grazing angles while a large roughness results in a smooth specular response around grazing angles.
Specular Map
0.5 and 1 respectively

Specular Map=0.0, 0.5 and 1 respectively

This map drives the strength of the specular reflection.
Specular Color Map
This map drives the color of the specular reflection.

Specular Color Map=yellow, green, red respectively

This map drives the color of the specular reflection.
Transmission Map

Roughness Map=0.2 and Transmission Map=0.0, 0.5 and 1 respectively

This map adjusts the amount of light that is transmitted by the surface rather than treated as diffuse. A value of 1.0 means that 100 percent of the light that penetrates the surface is transmitted through. The Volume attribute under the transmission tab determines if the material is treated as volume with absorption and refraction. The Roughness Map defines the transparency's clarity, where 0.0 is clear like window glass and higher values appear like frosted glass.
Note: ActiveShade is required to preview the transmission attribute.
Note: Accurate preview requires a scene units in meters and objects that are not scaled.

Roughness Map=0.2, Transmission Map=1, Volume Thickness=0.0, 0.5, 1 respectively

An increase in the Volume Thickness creates a thicker layer when light is refracted through the material.
IOR
The index of refraction (IOR) controls the amount by which the material refracts transmitted light.

Thickness = 1, IOR = 1.5, 3, 50 respectively

The default IOR value is 1.5. The following table lists common IOR values:
Material IOR value

Air

1.0003

Water

1.0003

Glass

1.5 to 1.7

Diamond

2.418

Note: IOR can only be defined as a constant value across the texture coordinates of a model in glTF. It is never defined with a texture map.
Note: The Transmission parameter must be enabled before the IOR parameter can be modified.

Known Limitations

  • The glTF material expects only RGB input (no alpha).
  • Textures that get auto-packed generate their data from the Lightness of the bitmap if you think in terms of HSL (in MAXScript, this is the color.value or color.v ).
  • Using a Multi/Sub-Object Material with empty material slots can cause incorrect materials on the exported faces.
  • Textures that get packed must share same dimensions and texture transforms or else the results will not be as expected.
  • The enabled/disabled state of some UI elements in the glTF Material do not properly update with Undo/Redo. Changing the current material in the material editor, then reselecting the material will fix that state.
  • Although the Unlit preview will render emission/illumination in active shade, it does not illuminate in glTF viewers.
  • Maps that get packed must share the same dimensions.

Sample Download

A downloadable sample folder containing a scene created in 3ds Max which makes use of the glTF Material node and attributes in texturing all assets present in the scene.

Click on the link below to download the sample folder (folder contains 3ds Max scene and all bitmap textures).

Patio Sample Scene

Parent topic: General Materials

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