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

# unproject(_:from:to:ontoPlane:)

Unprojects a point from the view onto a plane in 3D world coordinates.

## Declaration

```swift
func unproject(_ point: CGPoint, from space: some CoordinateSpaceProtocol, to realitySpace: some RealityCoordinateSpace, ontoPlane planeTransform: float4x4) -> SIMD3<Float>?
```

## Parameters

- `point`: A point in the provided coordinate space.
- `space`: The 2D coordinate space in which to interpret the point.
- `realitySpace`: The 3D coordinate space in which planeTransform interprets the point.
- `planeTransform`: The transform used to define the coordinate system of the plane relative to the scene. The coordinate system’s positive y-axis is assumed to be the normal of the plane.

## Return Value

Return Value 3D position in realitySpace, or nil if unprojection is not possible.

## Discussion

Discussion A 2D point in the view’s coordinate space can refer to any point along a line segment in the 3D coordinate space. Unprojecting gets the 3D position of the point along this line segment that intersects the provided plane. note: Unprojection is not possible if the plane is parallel to the line segment, or if the view does not have a currently active camera.