There are many approaches to creating realistic-looking materials for 3D objects. However, not all of them are suitable for transmission over the Web, and many have a prohibitively steep learning curve. Physically Based Rendering (PBR) has emerged as an artist-friendly, intuitive, expressive, and robust technique for adding materials to 3D objects. The Khronos 3D Formats Working Group has embraced this approach, and over the past few years, they have created formal glTF extensions for a variety of PBR materials. glTF’s growing set of PBR material extensions allow artists to create strikingly realistic 3D objects – suitable for cross-platform applications including browsers, mobile devices, native applications and more – that will perform consistently across a wide range of viewers and devices.