Babylon.js is an open-source 3D engine for the browser that renders with WebGL or WebGPU and includes a scene graph, PBR materials, glTF loading, Havok physics, a GUI layer and WebXR. Use when a user asks to build a 3D scene, game, product configurator or VR/AR experience with Babylon.js, load a glTF/GLB model, add physics or in-scene UI, switch to WebGPU, or shrink a Babylon.js bundle.