Material Type File Specification

Material type files (*.materialtype) are in written JSON format and contain the following elements.


  • groups: A list of property groups that appear in the Inspector window of the Material Editor. Each group contains the following:
    • id: An identifier for this group that is unique to this material type. The value must be formatted in C-style.
    • displayName: The given name of this group that will appear in the Material Editor.
    • description: The given description of this group that will appear as tooltips in the Material Editor.
The general group is built-in and always available, even if there is no general group defined in the groups section. This group is typically used to contain any basic properties of this material type.
  • properties: Defines the groups of properties that can be configured in a material file. Each group is defined as a key/value pair, where key is the group id, and value is an array of property definitions.

    Material properties support the following data types:

    • Bool
    • Int
    • UInt
    • Float
    • Vector2
    • Vector3
    • Vector4
    • Color
    • Image
    • Enum


An array of references to shader files (.shader). Each reference contains the following values.

  • file: The path to the shader file. The path must be relative to the asset root or to the material type file.
  • tag: A unique name for this shader item that can be used to reference the shader from other places in the material type definition. It must be a C-Style identifier.

In this example, we reference the ShadowMap and DepthPass shaders.

"shaders": [
        "file": "../ShadowMap.shader",
        "tag": "shadowmap"
        "file": "../DepthPass.shader",
        "tag": "depth"


An array of material functors. Each one reads material property values, performs some logic or calculations, and sets shader inputs accordingly. These can be defined in Lua or C++. Each functor data contains the following:

  • type: The name of the functor type. This will be “Lua” for custom Lua script functors, or the name of specialized functor type (defined in C++).

  • args: An object containing key/value pairs of all the arguments to send to this functor. The attributes vary depending on functor type. For ‘Lua’ functors, there is a single ‘file’ argument that references the Lua file.

To do:

Need a list of available functor types and their expected arguments.

A GitHub issue has been created for this task here.

uvNameMap (optional)

This array lists default identifiers for mesh UV streams.

To do:

Need a document about UV streams.

A GitHub issue has been created for this task here.