Materials

Materials are embedded into a .gltf or .glb file

Note: You can’t currently dynamically change the materials of a 3D model from your scene’s code ,unless this is a primitive shape.

Materials

With glTF 2.0, we leaped headlong into physically-based rendering (PBR), where the canonical way of expressing what a mesh looks like is by describing its visible material in fundamental attributes like "how rough is this surface".

By contrast, FBX's material support remains largely in the older world of Lambert and Phong, with simpler and more direct illumination and shading models. These modes are inherently incompatible — for example, textures in the old workflow often contain baked lighting of the type that would arise naturally in a PBR environment.

Some material settings remain well supported and transfer automatically:

• Emissive constants and textures

• Occlusion maps

• Normal maps

This leaves the other traditional settings, first of Lambert:

• Ambient — this is anathema in the PBR world, where such effects should emerge naturally from the fundamental color of the material and any ambient lighting present.

• Diffuse — the material's direction-agnostic, non-specular reflection, and additionally, with Blinn/Phong:

• Specular — a more polished material's direction-sensitive reflection,

• Shininess — just how polished the material is; a higher value here yields a more mirror-like surface.

(All these can be either constants or textures.)