Build interactive features such as: Input handling (controllers, hands, action sets, haptics) Scene/interaction systems (grabbing, ray interactions, UI in 3D) Rendering and performance optimizations (frame pacing, latency-sensitive updates) Integrate platform/runtime features where applicable (tracking spaces, anchor-like constructs, passthrough/scene understanding if available via extensions). Experience with a real-time engine or framework such as: Unity (C#) and OpenXR plugin ecosystem, or Unreal (C++) XR pipeline, or Custom/native OpenXR rendering with Vulkan/OpenGL/DirectX Understanding of rendering/perf constraints for XR (72/90/120 FPS targets, GPU/CPU bottlenecks, latency).