# Entity.ChildCollection A collection of child entities. ``` @MainActor @preconcurrency struct ChildCollection ``` ## Topics ### Accessing collection members [`subscript(Int) -> Entity`](/documentation/RealityKit/Entity/ChildCollection/subscript(_:)) Accesses the element at the specified position. (See `Collection.subscript`.) ### Adding entities [`func append(contentsOf: S, preservingWorldTransforms: Bool)`](/documentation/RealityKit/Entity/ChildCollection/append(contentsOf:preservingWorldTransforms:)-7g61) Adds the specified list of entity as children to this entity. [`func append(Entity, preservingWorldTransform: Bool)`](/documentation/RealityKit/Entity/ChildCollection/append(_:preservingWorldTransform:)) Adds the specified entity as a child to this entity. [`func append(contentsOf: [Entity], preservingWorldTransforms: Bool)`](/documentation/RealityKit/Entity/ChildCollection/append(contentsOf:preservingWorldTransforms:)-7p4hd) Adds the specified list of entity as children to this entity. ### Removing entities [`func remove(Entity, preservingWorldTransform: Bool)`](/documentation/RealityKit/Entity/ChildCollection/remove(_:preservingWorldTransform:)) Removes the specified child from this entity. [`func remove(at: Int, preservingWorldTransform: Bool)`](/documentation/RealityKit/Entity/ChildCollection/remove(at:preservingWorldTransform:)) Removes the specified child from this entity. [`func removeAll(preservingWorldTransforms: Bool)`](/documentation/RealityKit/Entity/ChildCollection/removeAll(preservingWorldTransforms:)) [`func removeAll(keepCapacity: Bool, preservingWorldTransforms: Bool)`](/documentation/RealityKit/Entity/ChildCollection/removeAll(keepCapacity:preservingWorldTransforms:)) Removes all children from this entity. ### Replacing entities [`func replaceAll([Entity], preservingWorldTransforms: Bool)`](/documentation/RealityKit/Entity/ChildCollection/replaceAll(_:preservingWorldTransforms:)-4mgff) Removes all children from this entity and adds the specified list of entities as the new children. [`func replaceAll(S, preservingWorldTransforms: Bool)`](/documentation/RealityKit/Entity/ChildCollection/replaceAll(_:preservingWorldTransforms:)-1vwk4) Removes all children from this entity and adds the specified list of entities as the new children. ### Iterating over collection of entities [`struct IndexingIterator`](/documentation/RealityKit/Entity/ChildCollection/IndexingIterator) ### Transforming entities ### Reordering entities ### Describing a collection [`var description: String`](/documentation/RealityKit/Entity/ChildCollection/description) A textual representation of this instance. (See `CustomStringConvertible`.) ### Counting entities ### Excluding entities ### Manipulating indices [`var startIndex: Int`](/documentation/RealityKit/Entity/ChildCollection/startIndex) The position of the first element in a nonempty collection. (See `Collection.startIndex`.) [`var endIndex: Int`](/documentation/RealityKit/Entity/ChildCollection/endIndex) TThe collection’s “past the end” position—that is, the position one greater than the last valid subscript argument. (See `Collection.endIndex`.) [`func index(after: Int) -> Int`](/documentation/RealityKit/Entity/ChildCollection/index(after:)) Returns the position immediately after the given index. (See `Collection.index`.) ### Instance Methods [`func append(contentsOf:preservingWorldTransforms:)`](/documentation/RealityKit/Entity/ChildCollection/append(contentsOf:preservingWorldTransforms:)) Adds the specified list of entity as children to this entity. [`func replaceAll(_:preservingWorldTransforms:)`](/documentation/RealityKit/Entity/ChildCollection/replaceAll(_:preservingWorldTransforms:)) Removes all children from this entity and adds the specified list of entities as the new children. ### Default Implementations [CustomStringConvertible Implementations](/documentation/RealityKit/Entity/ChildCollection/CustomStringConvertible-Implementations) [EntityCollection Implementations](/documentation/RealityKit/Entity/ChildCollection/EntityCollection-Implementations) ## Relationships ### Conforms To [`Copyable`](/documentation/Swift/Copyable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Sequence`](/documentation/Swift/Sequence) [`Escapable`](/documentation/Swift/Escapable) [`Sendable`](/documentation/Swift/Sendable) [`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible) [`EntityCollection`](/documentation/RealityKit/EntityCollection) [`Collection`](/documentation/Swift/Collection) --- 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)