GLB / glTF

https://medium.com/@matthewmain/how-to-import-a-3d-blender-object-into-a-three-js-project-as-a-gltf-file-5a67290f65f2 Von Blender nach Three JS als glTF
https://developers.facebook.com/docs/sharing/3d-posts/glb-tutorials/ - Facebook Manual
https://www.khronos.org/blog/art-pipeline-for-gltf - Übersicht über den Workflow nach glTF

glTF - Spezifikation

The glTF format supports the following textures for the Metallic-Roughness PBR model:

   Base Color
   Metallic
   Roughness
   Normal
   Ambient Occlusion
   Emission

The format does expect the textures in a specific format, however. The Base Color, Normal, and Emission textures are saved as individual files, preferably a PNG as the format is lossless. The Ambient Occlusion, Roughness, and Metallic textures are saved in a single channel-packed texture to reduce the number of texture loads. The textures need to be packed into the channels of your texture as follows:

   Red: Ambient Occlusion
   Green: Roughness
   Blue: Metallic

Going forward, I will refer to this channel-packed texture as the ORM texture for Occlusion, Roughness, and Metallic.