# LowLevelMeshResource.Layout An object that describes a set of attributes that share a buffer index, offset, and stride. ``` struct Layout ``` ## Overview If you interleave your data (that is, represent it with a structure), use one `Layout` object where `bufferStride` equals `MemoryLayout.stride`. If you store attributes separately, use one `Layout` per attribute. ## Topics ### Creating a layout [`init(bufferIndex: Int, bufferOffset: Int, bufferStride: Int, stepFunction: MTLVertexStepFunction, stepRate: Int)`](/documentation/RealityKit/LowLevelMeshResource/Layout/init(bufferIndex:bufferOffset:bufferStride:stepFunction:stepRate:)) Creates a layout with the given buffer index, offset, stride, step function, and step rate. ### Configuring vertex stepping [`var stepFunction: MTLVertexStepFunction`](/documentation/RealityKit/LowLevelMeshResource/Layout/stepFunction) Determines how the vertex shader steps through the data in this layout. [`var stepRate: Int`](/documentation/RealityKit/LowLevelMeshResource/Layout/stepRate) The number of instances that share the same per-instance vertex data. ### Initializers [`init()`](/documentation/RealityKit/LowLevelMeshResource/Layout/init()) Creates a layout with all fields set to their zero/default values. ### Instance Properties [`var bufferIndex: Int`](/documentation/RealityKit/LowLevelMeshResource/Layout/bufferIndex) The index of the buffer to use for this layout. [`var bufferOffset: Int`](/documentation/RealityKit/LowLevelMeshResource/Layout/bufferOffset) The byte offset into the buffer for the first byte of this layout. [`var bufferStride: Int`](/documentation/RealityKit/LowLevelMeshResource/Layout/bufferStride) The distance, in bytes, between consecutive vertices for attributes using this layout. ## Relationships ### Conforms To [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Sendable`](/documentation/Swift/Sendable) [`Equatable`](/documentation/Swift/Equatable) --- 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)