---
title: curveBasis
framework: metal
role: symbol
role_heading: Instance Property
path: metal/mtl4accelerationstructuremotioncurvegeometrydescriptor/curvebasis
---

# curveBasis

Sets the curve basis function, determining how Metal interpolates the control points.

## Declaration

```swift
var curveBasis: MTLCurveBasis { get set }
```

## Discussion

Discussion Defaults to MTLCurveBasisBSpline. All keyframes share the same curve basis function.