SceneKit

1. Essentials

   Covers SCNScene, SCNView, SceneView.

2. Scene Structure

   Covers Organizing a Scene with Nodes, SCNNode, SCNReferenceNode.

3. Display and Interactivity

   Covers SCNSceneRenderer, SCNSceneRendererDelegate, SCNLayer, SCNRenderer.

4. Lighting, Cameras, and Shading

   Covers SCNLight, SCNCamera, SCNMaterial, SCNMaterialProperty.

5. Geometry

   Covers SCNGeometry, SCNGeometrySource, SCNGeometryElement, Built-in Geometry Types.

6. Animation and Constraints

   Covers Animation, Constraints, SCNSkinner, SCNMorpher.

7. Physics

   Covers Physics Simulation.

8. Particle Systems

   Covers SCNParticleSystem, SCNParticlePropertyController.

9. Audio

   Covers SCNAudioSource, SCNAudioPlayer.

10. Renderer Customization

    Covers SCNShadable, SCNProgram, SCNBufferStream, SCNTechnique.

11. Scene Asset Import

    Covers SCNSceneSource.

12. JavaScript

    Covers SCNExportJavaScriptModule(_:).

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.