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  "identifier" : "/documentation/ARKit/ARCamera/unprojectPoint(_:ontoPlane:viewRotationAngle:viewportSize:)",
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# unprojectPoint(_:ontoPlane:viewRotationAngle:viewportSize:)

Unprojects a 2D point in image space onto a 3D plane in world space.

```
@nonobjc func unprojectPoint(_ point: CGPoint, ontoPlane planeTransform: simd_float4x4, viewRotationAngle: CGFloat, viewportSize: CGSize) -> simd_float3?
```

## Parameters

`point`

The 2D point in the image to unproject.

`planeTransform`

The 4x4 matrix representing the plane in world space.

`viewRotationAngle`

The view rotation angle, in degrees. Prefer it over an interface orientation, whose reported value
cannot always be relied upon. Obtain it from `ARSession.viewRotationAngle`.

`viewportSize`

The size of the viewport.

## Return Value

The 3D point in world space, or `nil` if the point cannot be unprojected.

---

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