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# MaterialFunction

The abstract superclass for objects representing compute functions for RealityKit custom materials .

```
protocol MaterialFunction
```

## Overview

This class is the parent of, and contains common properties and methods for
[`CustomMaterial.GeometryModifier`](/documentation/RealityKit/CustomMaterial/GeometryModifier)
and [`CustomMaterial.SurfaceShader`](/documentation/RealityKit/CustomMaterial/SurfaceShader). Don’t create an instance of this superclass yourself.

## Topics

### Instance Properties

[`var constantValues: MTLFunctionConstantValues`](/documentation/RealityKit/MaterialFunction/constantValues)

The constant values to use when RealityKit creates your
function. These correspond to constants defined in your metal code.

[`var library: any MTLLibrary`](/documentation/RealityKit/MaterialFunction/library)

Metal Library containing the given function.

[`var name: String`](/documentation/RealityKit/MaterialFunction/name)

Name of function found in library

## Relationships

### Conforming Types

[`SurfaceShader`](/documentation/RealityKit/CustomMaterial/SurfaceShader)

[`GeometryModifier`](/documentation/RealityKit/CustomMaterial/GeometryModifier)

---

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