A material decides how light leaving a surface reaches the camera. Babylon.js 89,603 ships two families that cover most scenes: StandardMaterial, the Blinn-Phong model of Specular Lighting and Fog, and PBRMaterial, the metallic-roughness model of Normal Maps and PBR. Both generate their shaders for you, in GLSL on Engine and WGSL on WebGPUEngine, from the features you switch on; BookNest's books get their cover art from them at the end of the section.