---
title: "unproject(_:ontoPlane:)"
framework: realitykit
role: symbol
role_heading: Instance Method
path: "realitykit/arview/unproject(_:ontoplane:)"
---

# unproject(_:ontoPlane:)

Maps a 2D point from the view’s coordinate system onto the given plane in 3D space.

## Declaration

```swift
@MainActor @preconcurrency func unproject(_ point: CGPoint, ontoPlane planeTransform: float4x4) -> SIMD3<Float>?
```

## Parameters

- `point`: The point in the view’s coordinate system.
- `planeTransform`: A transform used to define the coordinate system of the plane. The positive y-axis is taken as the normal of the plane.

## Return Value

Return Value The 3D position in world coordinates, or nil if the mapping isn’t possible.

## See Also

### Mapping between coordinate spaces

- [project(_:)](realitykit/arview/project(_:).md)
- [unproject(_:ontoPlane:relativeToCamera:)](realitykit/arview/unproject(_:ontoplane:relativetocamera:).md)
- [unproject(_:viewport:)](realitykit/arview/unproject(_:viewport:).md)
- [ray(through:)](realitykit/arview/ray(through:).md)