# LightmapComponent Describes how a lightmap is applied to parts of the scene. ``` struct LightmapComponent ``` ## Overview [`LightmapComponent`](/documentation/RealityKit/LightmapComponent) specifies which children of its owning entity should have a lightmap applied to them, and connects those children to their corresponding data in a [`LightmapResource`](/documentation/RealityKit/LightmapResource). To use [`LightmapComponent`](/documentation/RealityKit/LightmapComponent), first create a [`LightmapResource`](/documentation/RealityKit/LightmapResource) using textures produced by an offline baking process. Then, create a new [`LightmapComponent`](/documentation/RealityKit/LightmapComponent) backed by the [`LightmapResource`](/documentation/RealityKit/LightmapResource), and use the [`entityIndexInLightmapResource`](/documentation/RealityKit/LightmapComponent/entityIndexInLightmapResource) property to map each entity that you wish to be lightmapped, to its corresponding slot in the lightmap resource. Finally, add the [`LightmapComponent`](/documentation/RealityKit/LightmapComponent) to an entity that sits above all of the lightmapped entities in the hierachy. ## See Also [`LightmapResource`](/documentation/RealityKit/LightmapResource) A resource containing references to lightmap texture atlases and descriptions of how parts of the atlases map to meshes in the scene. --- 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)