SceneKit API Reference & Migration Mapping

Complete API reference for SceneKit with RealityKit equivalents for every major concept.

When to Use This Reference

Use this reference when:

Looking up SceneKit → RealityKit API equivalents during migration

Checking specific SceneKit class properties or methods

Planning which SceneKit features have direct RealityKit counterparts

Understanding architectural differences between scene graph and ECS

Part 1: SceneKit → RealityKit Concept Mapping

Core Architecture

SceneKit

RealityKit

Notes

SCNScene

RealityViewContent

/

Entity

(root)

RealityKit scenes are entity hierarchies

SCNNode

Entity

Lightweight container in both

SCNView

RealityView

(SwiftUI)

ARView

for UIKit on iOS

SceneView

(SwiftUI)

RealityView

SceneView deprecated iOS 26

SCNRenderer

RealityRenderer

Low-level Metal rendering

Node properties

Components

ECS separates data from hierarchy

SCNSceneRendererDelegate

System

/

SceneEvents.Update

Frame-level updates

.scn

files

.usdz

/

.usda

files

Convert with

xcrun scntool

Geometry & Rendering

SceneKit

RealityKit

Notes

SCNGeometry

MeshResource

RealityKit generates from code or loads USD

SCNBox

,

SCNSphere

, etc.

MeshResource.generateBox()

,

.generateSphere()

Similar built-in shapes

SCNMaterial

SimpleMaterial

,

PhysicallyBasedMaterial

PBR-first in RealityKit

SCNMaterial.lightingModel = .physicallyBased

PhysicallyBasedMaterial

Default in RealityKit

SCNMaterial.diffuse

PhysicallyBasedMaterial.baseColor

Different property name

SCNMaterial.metalness

PhysicallyBasedMaterial.metallic

Different property name

SCNMaterial.roughness

PhysicallyBasedMaterial.roughness

Same concept

SCNMaterial.normal

PhysicallyBasedMaterial.normal

Same concept

Shader modifiers

ShaderGraphMaterial

/

CustomMaterial

No direct port — must rewrite

SCNProgram

(custom shaders)

CustomMaterial

with Metal functions

Different API surface

SCNGeometrySource

MeshResource.Contents

Low-level mesh data

Transforms & Hierarchy

SceneKit

RealityKit

Notes

node.position

entity.position

Both SCNVector3 / SIMD3

node.eulerAngles

entity.orientation

(quaternion)

RealityKit prefers quaternions

node.scale

entity.scale

Both SIMD3

node.transform

entity.transform

4×4 matrix

node.worldTransform

entity.transform(relativeTo: nil)

World-space transform

node.addChildNode(_:)

entity.addChild(_:)

Same hierarchy concept

node.removeFromParentNode()

entity.removeFromParent()

Same concept

node.childNodes

entity.children

Children collection

node.parent

entity.parent

Parent reference

node.childNode(withName:recursively:)

entity.findEntity(named:)

Named lookup

Lighting

SceneKit

RealityKit

Notes

SCNLight

(

.omni

)

PointLightComponent

Point light

SCNLight

(

.directional

)

DirectionalLightComponent

Sun/directional light

SCNLight

(

.spot

)

SpotLightComponent

Cone light

SCNLight

(

.area

)

No direct equivalent

Use multiple point lights

SCNLight

(

.ambient

)

EnvironmentResource

(IBL)

Image-based lighting preferred

SCNLight

(

.probe

)

EnvironmentResource

Environment probes

SCNLight

(

.IES

)

No direct equivalent

Use light intensity profiles

Camera

SceneKit

RealityKit

Notes

SCNCamera

PerspectiveCamera

entity

Entity with camera component

camera.fieldOfView

PerspectiveCameraComponent.fieldOfViewInDegrees

Same concept

camera.zNear

/

camera.zFar

PerspectiveCameraComponent.near

/

.far

Clipping planes

camera.wantsDepthOfField

Post-processing effects

Different mechanism

camera.motionBlurIntensity

Post-processing effects

Different mechanism

allowsCameraControl

Custom gesture handling

No built-in orbit camera

Physics

SceneKit

RealityKit

Notes

SCNPhysicsBody

PhysicsBodyComponent

Component-based

.dynamic

.dynamic

Same mode

.static

.static

Same mode

.kinematic

.kinematic

Same mode

SCNPhysicsShape

CollisionComponent

/

ShapeResource

Separate from body in RealityKit

categoryBitMask

CollisionGroup

Named groups vs raw bitmasks

collisionBitMask

CollisionFilter

Filter-based

contactTestBitMask

CollisionEvents.Began

subscription

Event-based contacts

SCNPhysicsContactDelegate

scene.subscribe(to: CollisionEvents.Began.self)

Combine-style events

SCNPhysicsField

PhysicsBodyComponent

forces

Apply forces directly

SCNPhysicsJoint

PhysicsJoint

Similar joint types

Animation

SceneKit

RealityKit

Notes

SCNAction

entity.move(to:relativeTo:duration:)

Transform animation

SCNAction.sequence

Animation chaining

Less declarative in RealityKit

SCNAction.group

Parallel animations

Apply to different entities

SCNAction.repeatForever

AnimationPlaybackController

repeat

Different API

SCNTransaction

(implicit)

No direct equivalent

Explicit animations only

CAAnimation

bridge

entity.playAnimation()

Load from USD

SCNAnimationPlayer

AnimationPlaybackController

Playback control

Morph targets

Blend shapes in USD

Load via USD files

Interaction

SceneKit

RealityKit

Notes

hitTest(_:options:)

RealityViewContent.entities(at:)

Different API

Gesture recognizers on SCNView

ManipulationComponent

Built-in drag/rotate/scale

allowsCameraControl

Custom implementation

No built-in orbit

AR Integration

SceneKit

RealityKit

Notes

ARSCNView

RealityView

+

AnchorEntity

Legacy → modern

ARSCNViewDelegate

AnchorEntity

auto-tracking

Event-driven

renderer(_:didAdd:for:)

AnchorEntity(.plane)

Declarative anchoring

ARWorldTrackingConfiguration

SpatialTrackingSession

iOS 18+

Part 2: Scene Graph API

SCNScene

// Loading

let

scene

=

SCNScene

(

named

:

"scene.usdz"

)

!

let

scene

=

try

SCNScene

(

url

:

url

,

options

:

[

.

checkConsistency

:

true

,

.

convertToYUp

:

true

]

)

// Properties

scene

.

rootNode

// Root of node hierarchy

scene

.

background

.

contents

// Skybox (UIImage, UIColor, MDLSkyCubeTexture)

scene

.

lightingEnvironment

.

contents

// IBL environment map

scene

.

fogStartDistance

// Fog near

scene

.

fogEndDistance

// Fog far

scene

.

fogColor

// Fog color

scene

.

isPaused

// Pause simulation

SCNNode

// Creation

let

node

=

SCNNode

(

)

let

node

=

SCNNode

(

geometry

:

SCNBox

(

width

:

1

,

height

:

1

,

length

:

1

,

chamferRadius

:

0

)

)

// Transform

node

.

position

=

SCNVector3

(

x

,

y

,

z

)

node

.

eulerAngles

=

SCNVector3

(

pitch

,

yaw

,

roll

)

node

.

scale

=

SCNVector3

(

1

,

1

,

1

)

node

.

simdPosition

=

SIMD3

<

Float

>

(

x

,

y

,

z

)

// SIMD variants available

node

.

pivot

=

SCNMatrix4MakeTranslation

(

0

,

-

0.5

,

0

)

// Offset pivot point

// Visibility

node

.

isHidden

=

false

node

.

opacity

=

1.0

node

.

castsShadow

=

true

node

.

renderingOrder

=

0

// Lower = rendered first

// Hierarchy

node

.

addChildNode

(

child

)

node

.

removeFromParentNode

(

)

node

.

childNodes

node

.

childNode

(

withName

:

"name"

,

recursively

:

true

)

node

.

enumerateChildNodes

{

child

,

stop

in

}

Part 3: Materials

Lighting Models

Model

Description

Use Case

.physicallyBased

PBR metallic-roughness

Realistic rendering (recommended)

.blinn

Blinn-Phong specular

Simple shiny surfaces

.phong

Phong specular

Classic specular highlight

.lambert

Diffuse only, no specular

Matte surfaces

.constant

Unlit, flat color

UI elements, debug visualization

.shadowOnly

Invisible, receives shadows

AR ground plane

Material Properties

let

mat

=

SCNMaterial

(

)

mat

.

lightingModel

=

.

physicallyBased

// Textures or scalar values

mat

.

diffuse

.

contents

=

UIImage

(

named

:

"albedo"

)

// Base color

mat

.

metalness

.

contents

=

0.0

// 0 = dielectric, 1 = metal

mat

.

roughness

.

contents

=

0.5

// 0 = mirror, 1 = rough

mat

.

normal

.

contents

=

UIImage

(

named

:

"normal"

)

// Normal map

mat

.

ambientOcclusion

.

contents

=

UIImage

(

named

:

"ao"

)

// AO map

mat

.

emission

.

contents

=

UIColor

.

blue

// Glow

mat

.

displacement

.

contents

=

UIImage

(

named

:

"height"

)

// Height map

// Options

mat

.

isDoubleSided

=

false

// Render both sides

mat

.

writesToDepthBuffer

=

true

mat

.

readsFromDepthBuffer

=

true

mat

.

blendMode

=

.

alpha

// .add, .subtract, .multiply, .screen

mat

.

transparencyMode

=

.

aOne

// .rgbZero for pre-multiplied alpha

Part 4: Physics

Body Types and Properties

// Dynamic body with custom shape

let

shape

=

SCNPhysicsShape

(

geometry

:

SCNSphere

(

radius

:

0.5

)

,

options

:

nil

)

let

body

=

SCNPhysicsBody

(

type

:

.

dynamic

,

shape

:

shape

)

body

.

mass

=

1.0

body

.

friction

=

0.5

body

.

restitution

=

0.3

// Bounciness

body

.

damping

=

0.1

// Linear damping

body

.

angularDamping

=

0.1

// Angular damping

body

.

isAffectedByGravity

=

true

body

.

allowsResting

=

true

// Sleep optimization

node

.

physicsBody

=

body

// Compound shapes

let

compound

=

SCNPhysicsShape

(

shapes

:

[

shape1

,

shape2

]

,

transforms

:

[

transform1

,

transform2

]

)

// Concave (static only)

let

concave

=

SCNPhysicsShape

(

geometry

:

mesh

,

options

:

[

.

type

:

SCNPhysicsShape

.

ShapeType

.

concavePolyhedron

]

)

Joint Types

Joint

Description

SCNPhysicsHingeJoint

Single-axis rotation (door)

SCNPhysicsBallSocketJoint

Free rotation around point (pendulum)

SCNPhysicsSliderJoint

Linear movement along axis (drawer)

SCNPhysicsConeTwistJoint

Limited rotation (ragdoll limb)

Part 5: Animation API

SCNAction Catalog

Category

Actions

Movement

move(by:duration:)

,

move(to:duration:)

Rotation

rotate(by:around:duration:)

,

rotateTo(x:y:z:duration:)

Scale

scale(by:duration:)

,

scale(to:duration:)

Fade

fadeIn(duration:)

,

fadeOut(duration:)

,

fadeOpacity(to:duration:)

Visibility

hide()

,

unhide()

Audio

playAudio(source:waitForCompletion:)

Custom

run

,

customAction(duration:action:)

Composition

sequence([])

,

group([])

,

repeat(_:count:)

,

repeatForever(_:)

Control

wait(duration:)

,

removeFromParentNode()

Timing Functions

action

.

timingMode

=

.

linear

// Default

action

.

timingMode

=

.

easeIn

// Slow start

action

.

timingMode

=

.

easeOut

// Slow end

action

.

timingMode

=

.

easeInEaseOut

// Slow start and end

action

.

timingFunction

=

{

t

in

// Custom curve

return

t

*

t

// Quadratic ease-in

}

Part 6: Constraints

Constraint

Purpose

SCNLookAtConstraint

Node always faces target

SCNBillboardConstraint

Node always faces camera

SCNDistanceConstraint

Maintains min/max distance

SCNReplicatorConstraint

Copies transform of target

SCNAccelerationConstraint

Smooths transform changes

SCNSliderConstraint

Locks to axis

SCNIKConstraint

Inverse kinematics chain

let

lookAt

=

SCNLookAtConstraint

(

target

:

targetNode

)

lookAt

.

isGimbalLockEnabled

=

true

// Prevent roll

lookAt

.

influenceFactor

=

0.8

// Partial constraint

node

.

constraints

=

[

lookAt

]

In RealityKit

No direct constraint system. Implement with

System

update logic or

entity.look(at:from:relativeTo:)

.

Part 7: Scene Configuration

SCNView Configuration

Property

Default

Description

antialiasingMode

.multisampling4X

MSAA level

preferredFramesPerSecond

60

Target frame rate

allowsCameraControl

false

Built-in orbit/pan/zoom

autoenablesDefaultLighting

false

Add default light if none

showsStatistics

false

FPS/node/draw count overlay

isTemporalAntialiasingEnabled

false

TAA smoothing

isJitteringEnabled

false

Temporal jitter for TAA

debugOptions

[]

.showPhysicsShapes

,

.showBoundingBoxes

,

.renderAsWireframe

Resources

WWDC

2014-609, 2014-610, 2017-604, 2019-612

Docs

/scenekit, /scenekit/scnscene, /scenekit/scnnode, /scenekit/scnmaterial, /scenekit/scnphysicsbody, /scenekit/scnaction

Skills

axiom-scenekit, axiom-realitykit, axiom-realitykit-ref