# LowLevelMesh.Layout An object that describes a set of attributes that share a buffer index, offset, and stride. ``` struct Layout ``` ## Overview Applications typically express their types using contiguous or interleaved (strided) memory. If you interleave your data (meaning that you represent it with a structure), use one `Layout` object where [`bufferStride`](/documentation/RealityKit/LowLevelMesh/Layout/bufferStride) is equal to `MemoryLayout.stride()`. If you store your attributes separately, use one `Layout` per attribute. ## Topics ### Creating a low-level mesh layout [`init(bufferIndex: Int, bufferOffset: Int, bufferStride: Int)`](/documentation/RealityKit/LowLevelMesh/Layout/init(bufferIndex:bufferOffset:bufferStride:)) ### Describing a low-level mesh layout [`var bufferIndex: Int`](/documentation/RealityKit/LowLevelMesh/Layout/bufferIndex) The index of the buffer to use for this layout. [`var bufferOffset: Int`](/documentation/RealityKit/LowLevelMesh/Layout/bufferOffset) The byte offset into the buffer for the first byte of this layout. [`var bufferStride: Int`](/documentation/RealityKit/LowLevelMesh/Layout/bufferStride) The distance, in bytes, between consecutive vertices for attributes using this layout. ### Creating a layout [`init(bufferIndex: Int, bufferOffset: Int, bufferStride: Int, stepFunction: MTLVertexStepFunction, stepRate: Int)`](/documentation/RealityKit/LowLevelMesh/Layout/init(bufferIndex:bufferOffset:bufferStride:stepFunction:stepRate:)) ### Configuring vertex stepping [`var stepFunction: MTLVertexStepFunction`](/documentation/RealityKit/LowLevelMesh/Layout/stepFunction) Determines how the vertex shader steps through the data in this layout. [`var stepRate: Int`](/documentation/RealityKit/LowLevelMesh/Layout/stepRate) The number of instances that share the same per-instance vertex data. ## Relationships ### Conforms To [`Sendable`](/documentation/Swift/Sendable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) --- 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)