# groupID An optional group identifier for the hover effect. ``` var groupID: HoverEffectComponent.GroupID? { get set } ``` ## Discussion The system activates the hover effect entities that have the same [`HoverEffectComponent.GroupID`](/documentation/RealityKit/HoverEffectComponent/GroupID) instance at the same time when a person looks at it or hovers over any entity in the group. ### Activating Hover Effects The system activates hover effect entities with a `groupID` independently from the hierarchical activation behavior. ```swift let boxSize = SIMD3(0.3, 0.1, 0.05) let modelComponent = ModelComponent( mesh: MeshResource.generateBox(size: boxSize, cornerRadius: 0.2), materials: [SimpleMaterial(color: .black, roughness: 0.5, isMetallic: false)] ) let collisionComponent = CollisionComponent( shapes: [ShapeResource.generateBox(size: boxSize)] ) let inputTargetComponent = InputTargetComponent() let hoverEntityA = Entity(components: modelComponent, collisionComponent, inputTargetComponent ) let hoverEntityB = hoverEntityA.clone(recursive: true) hoverEntityB.position.x = -0.2 hoverEntityB.position.y = -0.15 let hoverEntityBB = hoverEntityA.clone(recursive: true) hoverEntityBB.position.y = -0.15 let hoverEntityC = hoverEntityA.clone(recursive: true) hoverEntityC.position.x = 0.2 hoverEntityC.position.y = -0.15 content.add(hoverEntityA) hoverEntityA.addChild(hoverEntityB) hoverEntityB.addChild(hoverEntityBB) hoverEntityA.addChild(hoverEntityC) // Create hover effect component for the top entity in the scene. let hoverA = HoverEffectComponent( .highlight(HoverEffectComponent.HighlightHoverEffectStyle( color: .green, strength: 2.0 ))) hoverEntityA.components.set(hoverA) // Create hover effect components for the two children on the left side. var hoverB = HoverEffectComponent( .highlight(HoverEffectComponent.HighlightHoverEffectStyle( color: .yellow, strength: 2.0 ))) var hoverBB = HoverEffectComponent( .highlight(HoverEffectComponent.HighlightHoverEffectStyle( color: .orange, strength: 2.0 ))) // Create a `HoverEffectComponent.GroupID` instance for the children on the left side let leftGroupId = HoverEffectComponent.GroupID() hoverB.hoverEffect.groupID = leftGroupId hoverBB.hoverEffect.groupID = leftGroupId hoverEntityB.components.set(hoverB) hoverEntityBB.components.set(hoverBB) ``` In this example, the top entity, `entityA`, doesn’t have a group identifier. However, the left side entities, `entityB` and `entityBB`, have the same [`HoverEffectComponent.GroupID`](/documentation/RealityKit/HoverEffectComponent/GroupID) instance. The top entity `entityA` and its right child `entityC` both glow when a person activates either one in the right side hierarchical branch. However, the left child `entityB` and its descendent `entityBB` glow only when a person activates either one of them.  --- 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)