---
title: refit
framework: metal
role: symbol
role_heading: Type Property
path: metal/mtlaccelerationstructureusage/refit
---

# refit

An option that lets you update an acceleration structure after creating it.

## Declaration

```swift
static var refit: MTLAccelerationStructureUsage { get }
```

## Discussion

Discussion Apply this option to make a modifiable acceleration structure, which you can update over time, such as for geometry changes. By default, the framework builds immutable acceleration structures for performance. When you apply the refit option, the framework builds an acceleration structure more conservatively, which can reduce its intersection performance. note: Refitting an acceleration structure generally works better when the geometry changes are relatively small.

## See Also

### Applying options

- [preferFastBuild](metal/mtlaccelerationstructureusage/preferfastbuild.md)
- [preferFastIntersection](metal/mtlaccelerationstructureusage/preferfastintersection.md)
- [minimizeMemory](metal/mtlaccelerationstructureusage/minimizememory.md)
- [extendedLimits](metal/mtlaccelerationstructureusage/extendedlimits.md)