---
title: stepRate
framework: metal
role: symbol
role_heading: Instance Property
path: metal/mtlvertexbufferlayoutdescriptor/steprate
---

# stepRate

The interval at which the vertex and its attributes are presented to the vertex function.

## Declaration

```swift
var stepRate: Int { get set }
```

## Discussion

Discussion The default value is 1. The stepRate value, in conjunction with the stepFunction property, determines how often the function fetches new attribute data. The stepRate property is generally used when stepFunction is MTLVertexStepFunction.perInstance. If stepRate is equal to 1, new attribute data is fetched for every instance; if stepRate is equal to 2, new attribute data is fetched for every two instances, and so forth.

## See Also

### Organizing the vertex buffer layout

- [stepFunction](metal/mtlvertexbufferlayoutdescriptor/stepfunction.md)
- [stride](metal/mtlvertexbufferlayoutdescriptor/stride.md)
- [MTLVertexStepFunction](metal/mtlvertexstepfunction.md)