# onGeometryChange3D(for:of:action:) Returns a new view that arranges to call `action(value)` whenever the value computed by `transform(proxy)` changes, where `proxy` provides access to the view’s 3D geometry properties. ``` @MainActor @preconcurrency func onGeometryChange3D(for type: T.Type, of transform: @escaping (GeometryProxy3D) -> T, action: @escaping (T) -> Void) -> some View where T : Equatable ``` --- 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)