# LowLevelInstanceData ``` final class LowLevelInstanceData ``` ## Topics ### Initializers [`convenience init(instanceCount: Int) throws`](/documentation/RealityKit/LowLevelInstanceData/init(instanceCount:)) Creates a low-level instance data object with an instance count. [`init(instanceCount: Int, instanceCapacity: Int) throws`](/documentation/RealityKit/LowLevelInstanceData/init(instanceCount:instanceCapacity:)) Creates a low-level instance data object with an instance count and capacity. ### Instance Properties [`var instanceCapacity: Int`](/documentation/RealityKit/LowLevelInstanceData/instanceCapacity) The maximum number of instances this low-level instance data draws when set on a mesh instances component. [`var instanceCount: Int`](/documentation/RealityKit/LowLevelInstanceData/instanceCount) The current number of instances in this low-level instance data. ### Instance Methods [`func read(using: any MTLCommandBuffer) -> any MTLBuffer`](/documentation/RealityKit/LowLevelInstanceData/read(using:)) Retrieves the current per instance transform data, for GPU reading. [`func replace(using: any MTLCommandBuffer) -> any MTLBuffer`](/documentation/RealityKit/LowLevelInstanceData/replace(using:)) Retrieves a Metal buffer that you can use to replace the per instance transform data on GPU using Metal. [`func replaceMutableTransforms((UnsafeMutableBufferPointer) -> Void)`](/documentation/RealityKit/LowLevelInstanceData/replaceMutableTransforms(_:)) Replaces the per instance transform data synchronously on the CPU. [`func withMutableTransforms((UnsafeMutableBufferPointer) -> Void)`](/documentation/RealityKit/LowLevelInstanceData/withMutableTransforms(_:)) Updates the per instance transform data synchronously on the CPU. [`func withTransforms((UnsafeBufferPointer) -> Void)`](/documentation/RealityKit/LowLevelInstanceData/withTransforms(_:)) Reads the per instance transform data synchronously on the CPU. --- 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)