RealityKit API Reference

Complete API reference for RealityKit organized by category. Covers the Entity hierarchy, all built-in components, the System protocol, SwiftUI views (RealityView, Model3D), the material system, physics, animation, audio, and RealityRenderer for Metal integration.

When to Use This Reference

Use this reference when:

• Looking up specific RealityKit API signatures or properties
• Checking which component types are available
• Finding the right anchor type for an AR experience
• Browsing material properties and options
• Setting up physics body parameters
• Looking up animation or audio API details
• Checking platform availability for specific APIs
• Browsing the 27-cycle additions (navigation mesh, LOD, soft shadows, splats, reverb, cloth, ComputeGraph)

Example Prompts

• "What properties does PhysicallyBasedMaterial have?"
• "How do I create a RealityView with attachments?"
• "What are the ShapeResource types for collision?"
• "What events can I subscribe to in RealityKit?"
• "How do I set up spatial audio on an entity?"
• "What Entity subclasses are available?"
• "How do I render RealityKit content from my own Metal command buffer?"
• "Can I build a shader graph in Swift instead of Reality Composer Pro?"
• "How do I generate an image-based light at runtime from an HDR?"
• "Why won't import RealityCoreRenderer compile?"

What's Covered

• Entity API – Creation, properties (isEnabled, isAnchored, scene), hierarchy methods, 10 Entity subclasses (ModelEntity, AnchorEntity, PerspectiveCamera, lights, TriggerVolume)
• Component catalog – 20+ built-in components including Transform, ModelComponent, CollisionComponent, PhysicsBodyComponent, AnchoringComponent, InputTargetComponent, AccessibilityComponent
• MeshResource generators – Box, sphere, plane, cylinder, cone, text
• System protocol – SceneUpdateContext, EntityQuery (has/and/not), 8 scene event types (Update, DidAddEntity, CollisionEvents)
• RealityView API – Initializers (basic, update, placeholder, attachments), RealityViewContent, gesture integration (tap, drag, rotate, magnify)
• Model3D API – Simple display, phase handling, URL loading
• Material system – SimpleMaterial, PhysicallyBasedMaterial (full PBR), UnlitMaterial, OcclusionMaterial, VideoMaterial, TextureResource loading
• Animation – Transform animation with timing functions, USD animation playback, AnimationPlaybackController
• Audio – AudioFileResource, SpatialAudioComponent, AmbientAudioComponent, ChannelAudioComponent, playback control
• RealityRenderer – Low-level Metal integration for rendering RealityKit content to Metal textures
• RealityKit 27 additions – Navigation mesh pathfinding, level of detail, soft shadows, projective textures, physical space lighting (visionOS/macOS), lightmaps, Gaussian splats (visionOS), custom reverb meshes, ARKit object tracking, cloth simulation (ClothBodyComponent, iOS/macOS/visionOS 27), ComputeGraph framework (programmatic node graphs)

Renderer layer (iOS 27)

Reached through import RealityKit — the defining submodules cannot be imported directly.

• Frame loop – LowLevelRenderer (output, cameras, time, colorMatch, render(using:_:)), Configuration, Camera / CameraArray, RenderState
• Resource context – LowLevelRenderContext, …Standalone, …Lighting, …ShaderGraph
• Resources – LowLevelMeshResource, LowLevelTextureResource, LowLevelBufferResource, LowLevelInstanceTransformResource
• Materials and pipeline – LowLevelMaterialResource, LowLevelArgumentTable, LowLevelRenderPipelineState, LowLevelRenderTarget.Descriptor
• Draw, cull, sort – LowLevelMeshPart, LowLevelMeshInstance, LowLevelMeshInstanceArray, cullMeshInstances, sortMeshInstances
• Name-collision table – the 26-era LowLevelMesh / LowLevelTexture / LowLevelBuffer / LowLevelInstanceData versus their 27 *Resource counterparts
• ShaderGraph in Swift – ShaderGraph, NodeLibrary, NodeDefinition, Node, Edge, ShaderGraphMaterial.Program / Program.Descriptor
• GPU mesh deformation – LowLevelDeformationContext, LowLevelDeformation
• Runtime skybox and IBL – SkyboxGenerator, ImageBasedLightTextureGenerator, TextureSamplingQuality

Documentation Scope

This page documents the axiom-graphics skill. For architecture patterns, ECS guidance, and best practices, use the discipline skill. For troubleshooting, use the diagnostic skill.

• For ECS architecture and patterns, see RealityKit
• For troubleshooting, see RealityKit Diagnostics
• For SceneKit migration mapping, see SceneKit API Reference

Related

• RealityKit – ECS architecture patterns and best practices
• RealityKit Diagnostics – Troubleshooting invisible entities, physics, and rendering
• SceneKit API Reference – SceneKit equivalents for migration reference
• SpriteKit API Reference – 2D game framework (complements RealityKit's 3D)

Resources

WWDC: 2019-605, 2023-10080, 2023-10081, 2026-279

Docs: /realitykit, /realitykit/entity, /realitykit/realityview