---
title: constant
framework: scenekit
role: symbol
role_heading: Type Property
path: scenekit/scnmaterial/lightingmodel-swift.struct/constant
---

# constant

Uniform shading that incorporates ambient lighting only.

## Declaration

```swift
static let constant: SCNMaterial.LightingModel
```

## Discussion

Discussion This shading model calculates the color of a point on a surface with the following formula: color = ambient * al + diffuse The ambient and diffuse terms refer to the material’s properties. The al term is the sum of all ambient lights in the scene (a color).

## See Also

### Type Properties

- [blinn](scenekit/scnmaterial/lightingmodel-swift.struct/blinn.md)
- [lambert](scenekit/scnmaterial/lightingmodel-swift.struct/lambert.md)
- [phong](scenekit/scnmaterial/lightingmodel-swift.struct/phong.md)
- [physicallyBased](scenekit/scnmaterial/lightingmodel-swift.struct/physicallybased.md)
- [shadowOnly](scenekit/scnmaterial/lightingmodel-swift.struct/shadowonly.md)