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# init(_:)

Creates a new quaternion from a 4 x 4 rotation matrix.

```
init(_ rotationMatrix: simd_float4x4)
```

## Parameters

`rotationMatrix`

The rotation matrix.

## Discussion

This function ignores the last row and the last column of `rotationMatrix`, and is the equivalent of passing the upper-left 3 x 3 submatrix to [`init(_:)`](/documentation/simd/simd_quatf/init(_:)-1hlsg).

---

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