---
title: "init(bufferIndex:bufferOffset:bufferStride:stepFunction:stepRate:)"
framework: realitykit
role: symbol
role_heading: Initializer
path: "realitykit/lowlevelmeshresource/layout/init(bufferindex:bufferoffset:bufferstride:stepfunction:steprate:)"
---

# init(bufferIndex:bufferOffset:bufferStride:stepFunction:stepRate:)

Creates a layout with the given buffer index, offset, stride, step function, and step rate.

## Declaration

```swift
init(bufferIndex: Int, bufferOffset: Int = 0, bufferStride: Int, stepFunction: MTLVertexStepFunction = .perVertex, stepRate: Int = 1)
```

## Parameters

- `bufferIndex`: The index of the buffer this layout refers to.
- `bufferOffset`: The byte offset into the buffer for the first byte of this layout. Defaults to 0.
- `bufferStride`: The distance, in bytes, between consecutive vertices for attributes using this layout.
- `stepFunction`: How the vertex shader steps through this layout’s data. Defaults to .perVertex.
- `stepRate`: The number of instances that share the same per-instance data. Defaults to 1.