This model uses an older and no longer recommended feature of glTF, “spec/gloss” PBR materials. three.js has removed support for that feature, and allows only metal/rough PBR materials today.
You can losslessly convert the model to a metal/rough PBR workflow in a number of ways, the easiest of which might be:
npm install --global @gltf-transform/cli
gltf-transform metalrough input.glb output.glb
The model appears correctly in three.js after converting.
adamhead_webp_2k.glb (7.9 MB)
