# unproject(_:from:to:ontoPlane:) Unprojects a point from the view onto a plane in 3D world coordinates. ``` func unproject(_ point: CGPoint, from space: some CoordinateSpaceProtocol, to realitySpace: some RealityCoordinateSpace, ontoPlane planeTransform: float4x4) -> SIMD3? ``` ## 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 3D position in `realitySpace`, or nil if unprojection is not possible. ## 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. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)