RealityKit Diagnostics

Systematic RealityKit troubleshooting with decision trees and time-cost annotations. Covers the 7 most common RealityKit symptoms that waste developer time.

Symptoms This Diagnoses

Use when you're experiencing:

• Entity added but not visible in the scene
• AR anchor not tracking or content floating
• Tap/drag gestures not responding on 3D entities
• Frame rate dropping or stuttering
• Material looks wrong (too dark, too bright, incorrect colors)
• Physics bodies not colliding or passing through each other
• Multiplayer entities not syncing across devices
• Soft shadows not appearing despite setting lightSize (iOS 27)
• Navigation computePath returning nil vs. empty array behaving identically (iOS 27)

Example Prompts

• "I added an entity but nothing appears in my RealityView"
• "AR content isn't showing up on the table surface"
• "Tap gestures don't fire on my 3D entities"
• "RealityKit frame rate is dropping below 60fps"
• "My 3D model looks too dark, like there's no lighting"
• "Physics objects pass through each other"
• "Multiplayer entities don't appear on the other device"
• "import RealityCoreRenderer fails with 'implementation detail of RealityKit'" (iOS 27)
• "Is it LowLevelMesh or LowLevelMeshResource?" (iOS 27)
• "My model is dark and I have no pre-baked environment asset" (iOS 27)

Diagnostic Workflow

Mandatory first step: Enable debug visualization (.showStatistics, .showPhysics, .showAnchorOrigins, .showAnchorGeometry). If you cannot see collision shapes with .showPhysics, your CollisionComponent is missing or misconfigured. Fix collision before debugging gestures or physics.

Decision Trees

Symptom	Key Checks	Time Saved
Entity not visible	ModelComponent? Scale > 0? Behind camera? isEnabled?	30-60 min to 2-5 min
Anchor not tracking	Session running? Anchor type? minimumBounds? Device support?	20-45 min to 3-5 min
Gesture not responding	CollisionComponent? InputTargetComponent (visionOS)? Gesture on RealityView?	15-30 min to 2-3 min
Performance problems	Entity count? Shared resources? Component churn? Mesh-based collision?	1-3 hrs to 10-20 min
Material looks wrong	Lighting? baseColor? Metallic value? Texture semantic? Face culling?	15-45 min to 5-10 min
Physics not working	Both have CollisionComponent? Same anchor? Collision groups?	20-40 min to 5-10 min
Multiplayer sync	SynchronizationComponent? Codable? Ownership? Anchored?	30-60 min to 10-15 min

Common Mistakes Quick Reference

Mistake	Time Cost	Fix
No CollisionComponent on interactive entity	15-30 min	entity.generateCollisionShapes(recursive: true)
Missing InputTargetComponent on visionOS	10-20 min	Add InputTargetComponent()
Gesture on wrong view (not RealityView)	10-15 min	Attach .gesture() to RealityView
No lighting in non-AR scene	10-20 min	Add DirectionalLightComponent
Components/Systems not registered	10-15 min	Call registerComponent() / registerSystem() at launch
Physics across different anchors	20-40 min	Put interacting entities under same anchor
Soft shadows not appearing despite lightSize (iOS 27)	10-20 min	Shadow.quality must be .medium or .high — .low always renders hard shadows
computePath nil vs. empty array treated alike (iOS 27)	10-15 min	nil = no valid path exists; empty array = already at destination

Related

• RealityKit – ECS architecture, SwiftUI integration, physics, materials, anti-patterns
• RealityKit API Reference – Complete API tables for all RealityKit classes and components