# anisotropyLevel The degree to which an entity reflects light to create stretched or oblong highlights. ``` var anisotropyLevel: PhysicallyBasedMaterial.AnisotropyLevel { get set } ``` ## Discussion By default, PBR materials are isotropic; in other words, an entity that uses [`PhysicallyBasedMaterial`](/documentation/RealityKit/PhysicallyBasedMaterial) reflects light uniformly in all directions, mimicking the behavior of most real-world objects. Some objects, including those with many small parallel striations such as vinyl records, CDs, or straight hair, reflect light more in some directions than others, resulting in stretched or oblong specular highlights, as shown in the following figure.  This property controls the amount of anisotropy. It works together with [`anisotropyAngle`](/documentation/RealityKit/PhysicallyBasedMaterial/anisotropyAngle-swift.property), which defines the angle of elongation for the specular highlights. The following example specifies `anisotropyLevel` using single values for the entire material: ```swift material.anisotropyLevel = .AnisotropyLevel(floatLiteral: 0.5) ``` This example specifies `anisotropyLevel` using a UV-mapped image texture. ```swift if let anisoLevelResource = try? TextureResource.load(named: "entity_aniso_level") { let anisoLevelMap = MaterialParameters.Texture(sheenResource) material.anisotropyLevel = .init(texture: anisoLevelMap) } ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)