---
title: normal
framework: realitykit
role: symbol
role_heading: Instance Property
path: realitykit/custommaterial/normal-swift.property
---

# normal

A texture map that stores fine surface details for the entity.

## Declaration

```swift
var normal: CustomMaterial.Normal { get set }
```

## Discussion

Discussion Normal mapping is a real-time rendering technique that captures fine surface details for a model by using a texture instead of increasing the number of polygons in the model. It works by storing surface normals, which are vectors perpendicular to the surface of the model, from a much higher-resolution version of the same 3D object. A normal map stores each vector in the image by storing the vectors’ X, Y, and Z values as the R, G, and B components of the corresponding pixel in the UV-mapped image. For custom materials, normal is only used when lightingModel is CustomMaterial.LightingModel.lit or CustomMaterial.LightingModel.clearcoat and its surface shader calls params.surface().set_normal(). The normal map texture is still available to your surface shader function when using CustomMaterial.LightingModel.unlit. The following code loads a normal map texture and uses it to set this property: if let normalResource = try? TextureResource.load(named:"entity_normals") {     let normalMap = MaterialParameters.Texture(normalResource)     material.normal = .init(texture:normalMap) } The following Metal code shows how to sample the normal map texture in a surface shader and use it to set the fragment’s surface normal: // Retrieve the entity's texture coordinates. float2 uv = params.geometry().uv0();

// Entities loaded from USDZ or .reality files have texture coordinates // with a flipped y-axis. This adjusts for that. uv.y = 1.0 - uv.y;

// Sample the normal map to get the surface normal for this fragment. auto tex = params.textures(); float3 color = (float3)tex.normal().sample(textureSampler, uv).rgb;

// Set the fragment's surface normal using the sampled value. params.surface().set_normal(color); For more information on creating custom materials and writing shader functions, see Modifying RealityKit rendering using custom materials.

## See Also

### Setting the core properties

- [baseColor](realitykit/custommaterial/basecolor-swift.property.md)
- [roughness](realitykit/custommaterial/roughness-swift.property.md)
- [metallic](realitykit/custommaterial/metallic-swift.property.md)
- [emissiveColor](realitykit/custommaterial/emissivecolor-swift.property.md)
- [ambientOcclusion](realitykit/custommaterial/ambientocclusion-swift.property.md)
- [specular](realitykit/custommaterial/specular-swift.property.md)
- [clearcoat](realitykit/custommaterial/clearcoat-swift.property.md)
- [clearcoatRoughness](realitykit/custommaterial/clearcoatroughness-swift.property.md)
- [clearcoatNormal](realitykit/custommaterial/clearcoatnormal-swift.property.md)