scenekit

Guidance for maintaining and extending existing SceneKit 3D scenes and visualizations on iOS with Swift 6.3. SceneKit is Apple's high-level 3D rendering framework, providing a node-based scene graph, built-in geometry primitives, physically based materials, lighting, cameras, animation, and physics. The skill opens with an important caveat: as of WWDC 2025 SceneKit is officially deprecated and in maintenance mode (critical bug fixes only), so while existing apps keep working, new projects, major updates, USD/USDZ pipelines, and migration planning should be routed toward RealityKit. It walks through scene setup with SCNView in UIKit and loading SCNScene assets (.scn and .dae) including a consistency-check option, and explains the right-handed coordinate system in which nodes define position, orientation, and scale relative to their parent, with a preference for simd properties for performance. Geometry covers the built-in primitives (SCNBox, SCNSphere, SCNCylinder, and others) and node lookup by name or predicate. Materials span solid colors, textures, and full PBR with metalness and roughness, alongside the available lighting models (.physicallyBased, .blinn, .phong, .lambert, .constant, and .shadowOnly) and transparency options. Lighting details the ambient, directional, omni, and spot types, shadow configuration, and category bit masks, noting the maximum of eight lights per node. Cameras cover field of view, near and far planes, orthographic projection, depth of field, and HDR effects. Three animation approaches are compared - declarative SCNAction, implicit SCNTransaction, and explicit Core Animation via CABasicAnimation - and the skill continues into physics, particle systems, model loading, and SwiftUI integration through SceneView, closing with common mistakes and a review checklist.