Code API for SwiftUI

The Code API allows you to seamlessly integrate interactive 3D experiences into your projects, offering greater control and customization. It enables you to trigger actions, modify object properties, and create dynamic, responsive 3D environments directly from your existing code and user interface.

Important: The Code API allows your native interface to control properties in the Spline scene, and vice versa. However, it’s important to note that this is different from Real-time data APIs feature. To learn more about real-time data APIs, go here Real-time API).

Key capabilities

Event Listeners: React to real-time events within your 3D scenes.
Adjust Properties: Dynamically update position, scale, rotation, and more.
Trigger Transitions: Create transitions and animations based on events.
Adjust variables: Retrieve and update variables in a Spline scene.

Usage

Getting started

First, make sure you’re familiar with Native 3D Embeds for iOS and you can already embed 3D content in your SwiftUI projects.

struct ContentView: View {
    var body: some View {
        let url = URL(string: "https://build.spline.design/4-2CGowqS9z7MGA62D-B/scene.splineswift")!

        SplineView(sceneFileURL: url)
    }
}

Then, to access the API, create a SplineController object and pass it to SplineView initializer for the view you want to control.

struct ContentView: View {
		private var controller = SplineController()
		
    var body: some View {
        let url = URL(string: "https://build.spline.design/4-2CGowqS9z7MGA62D-B/scene.splineswift")!

        SplineView(sceneFileURL: url, controller: controller)
    }
}

Info: A controller object is only able to control a single view. Do NOT use the same controller for more views. See Handling multiple views section.

Read and modify Spline objects

You can query any Spline object in the scene via findObject(name:) or findObject(id:) functions. Then, you can read or write any of its properties. (You can get the ID of the object from the right-click context panel on the object).

struct ContentView: View {
    private var controller = SplineController()

    var body: some View {
        let url = URL(string: "https://build.spline.design/4-2CGowqS9z7MGA62D-B/scene.splineswift")!

        SplineView(sceneFileURL: url, controller: controller)

        Button("Move") {
            let cube = controller.findObject(name: "Cube")
            cube?.position.y += 10
        }
    }
}

The function returns nil if an object with the specified name was not found. Note that SplineView loads its content asynchronously, and so these and all other functions may return nil or may do nothing when the scene file still hasn’t finished loading. This is especially important when you want to access the API right at the start. For this, see the next example.

Listen to events

You can listen to any Spline Event you set in the Events panel of the editor by attaching a listener to the controller. You can find a list of all of the Spline Event listeners in the API section. To register event listeners when the view loads, make sure to use a task() or onAppear() modifier on the view that holds loaded content (SplineContent) and not the SplineView itself.

struct ContentView: View {
    private var controller = SplineController()

    var body: some View {
        let url = URL(string: "https://build.spline.design/4-2CGowqS9z7MGA62D-B/scene.splineswift")!

        SplineView(sceneFileURL: url, controller: controller) { phase in
            phase.content?.task {
                controller.addEventListener(.mouseUp) { obj in
                    if obj.name == "Cube" {
                        print("Cube clicked")
                    }
                }
            }
        }
    }
}

Trigger Spline events from outside

You can trigger any animation Event you set in the Events panel in the Spline Editor. You can use the emitEvent(_:) function, passing the event type and the name or ID of your object. (You can get the ID of the object from the right-click context panel on the object).

struct ContentView: View {
    private var controller = SplineController()

    var body: some View {
        let url = URL(string: "https://build.spline.design/4-2CGowqS9z7MGA62D-B/scene.splineswift")!

        SplineView(sceneFileURL: url, controller: controller)

        Button("Jump") {
            controller.emitEvent(.keyUp, nameOrUUID: "Cube")
        }
    }
}

Or you can query the spline object first, and then trigger the event:

struct ContentView: View {
    private var controller = SplineController()

    var body: some View {
        let url = URL(string: "https://build.spline.design/4-2CGowqS9z7MGA62D-B/scene.splineswift")!

        SplineView(sceneFileURL: url, controller: controller)

        Button("Jump") {
            let cube = controller.findObject(name: "Cube")
            cube?.emitEvent(.keyUp)
        }
    }
}

You can find a list of all of the Spline Events you can pass to the emitEvent(:_) function in the Spline Events section.

Handling multiple views

If you have several SplineView’s in a SwiftUI view hierarchy, and multiple of them are using the Code API, each view must have its own SplineController object.

struct ContentView: View {
    private var cubes = SplineController()
    private var spheres = SplineController()

    var body: some View {
        let urlCubes = ...
        let urlSpheres = ...
        let urlCylinders = ...

        SplineView(sceneFileURL: urlCubes, controller: cubes)
        SplineView(sceneFileURL: urlSpheres, controller: spheres)
        SplineView(sceneFileURL: urlCylinders)

        Button("Go Cube") {
            cubes.emitEvent(.keyUp, nameOrUUID: "Cube1")
        }

        Button("Go Sphere") {
            spheres.emitEvent(.keyUp, nameOrUUID: "Sphere1")
        }
    }
}

Updating scene variables

If you set up variables in your Spline scene from the editor, you can change them from code after the scene is loaded.

Note: If in the Spline Editor you have multiple variables with the same name, only the first one will be updated, so make sure to give unique names to the variables you want to update. Also note that the values you pass to your variables will be cast into their original type (number, boolean, or string).

struct ContentView: View {
    private var controller = SplineController()

    var body: some View {
        let url = URL(string: "https://build.spline.design/4-2CGowqS9z7MGA62D-B/scene.splineswift")!

        SplineView(sceneFileURL: url, controller: controller) { phase in
            phase.content?.task {
                controller.setNumberVariable(name: "opacity", value: 25)
            }
        }
    }
}

Download Xcode Demo

See how it works by downloading an Xcode demo project using Spline’s cloud iOS embeds and SwiftUI Code API. File

Trying out the demo:

On Xcode, go to File > Open and select the unzipped folder with your project;
Select iPhone as the build device – you can use your physical device or a simulator;
Trigger the preview on Xcode or press ▶️ to build your project.

Before Building

You might need to go into Signing & Capabilities, and under Signing, add your team manually.
Optionally, make sure to change the Bundle Identifier to a unique one.

3D Scene:

https://app.spline.design/file/f68f548d-9f78-4eee-90ce-fc72dafca6de

API

Spline Controller Methods

You can call all these different methods on the SplineController instance.

Name	Description
addEventListener(_:callback:)	Add an event listener for Spline events
emitEvent(_:nameOrUUID:)	Triggers a Spline event associated to an object with the provided name or UUID. Starts from the first state to the last state.
emitEventReverse(_:nameOrUUID:)	Triggers a Spline event associated to an object with the provided name or UUID in reverse order. Starts from the last state to the first state.
findObject(id:)	Searches through the scene’s children and returns the object with that UUID.
findObject(name:)	Searches through the scene’s children and returns the first object with that name.
setZoom(_:)	Sets the camera zoom, expects a number value > 0 where 1 is base zoom.
setNumberVariable(name:value:)	Updates value for passed variable by name.
setBoolVariable(name:value:)	Updates value for passed variable by name.
setStringVariable(name:value:)	Updates value for passed variable by name.
getNumberVariable(name:)	Get current value for a specific variable from its name
getBoolVariable(name:)	Get current value for a specific variable from its name
getStringVariable(name:)	Get current value for a specific variable from its name
stop()	Stop/Pause all rendering controls and events.
play()	Play/Resume rendering, controls and events.
setBackgroundColor(_:)	Manually sets the scene/canvas background color with a SIMD color value.

Spline Objects Methods and Properties

After retrieving a Spline Object with controller.findObject(id:) or controller.findObject(name:), there are a variety of properties and methods you can call on those.

Name	Description
name	Gets / Sets object name.
uuid	Gets object uuid.
position	Gets / Sets object position.
rotation	Gets / Sets object rotation.
scale	Gets / Sets object scale.
visible	Gets / Sets object vibility.
intensity	Only for light objects. Used to change the light intensity.
emitEvent(_:)	Force trigger an event defined in Spline Editor.
emitEventReverse(_:)	Force trigger an event defined in Spline Editor.

Spline Events

These are all the Spline event types that you can pass to the addEventListener(:), emitEvent(:) and emitEventReverse(_:) functions.

Name	Description
.mouseUp	Refers to the Spline `Mouse Up` event type
.mouseDown	Refers to the Spline `Mouse Down` event type
.mousePress	Refers to the Spline `Mouse Press` event type
.mouseHover	Refers to the Spline `Mouse Hover` event type
.keyUp	Refers to the Spline `Key Up` event type
.keyDown	Refers to the Spline `Key Down` event type
.keyPress	Refers to the Spline `Key Press` event type
.start	Refers to the Spline `Start` event type
.lookAt	Refers to the Spline `Look At` event type
.follow	Refers to the Spline `Follow` event type

🌳 Basics

🗂 Sharing, Collaboration, and Workspaces

🍭 Designing in 3D

🌸 Hana - a canvas for interactivity

✨ Spline AI

🕹️ Interaction (States, Events, and Actions)

🎞 Exporting your scene

💻 Importing Content

🌈 Materials & Shading

💡 Lighting

📸 Cameras

🧶 Integrations

🥳 Fun Facts

Policies

Key capabilities

Usage

Getting started

Read and modify Spline objects

Listen to events

Trigger Spline events from outside

Handling multiple views

Updating scene variables

Download Xcode Demo

API

Spline Controller Methods

Spline Objects Methods and Properties

Spline Events

​Key capabilities

​Usage

​Getting started

​Read and modify Spline objects

​Listen to events

​Trigger Spline events from outside

​Handling multiple views

​Updating scene variables

​Download Xcode Demo

​API

​Spline Controller Methods

​Spline Objects Methods and Properties

​Spline Events

Key capabilities

Usage

Getting started

Read and modify Spline objects

Listen to events

Trigger Spline events from outside

Handling multiple views

Updating scene variables

Download Xcode Demo

API

Spline Controller Methods

Spline Objects Methods and Properties

Spline Events