I am using the CC auto setup for Blender add-on v2.2.5. Using the add-on, I import my FBX model, set the build settings to basic, and click rebuild materials. I adjust the “Ah” shape key, and you can see that the jaw opens.
When I use a glb viewer, I try adjusting the “Ah” shape key, but the jaw won’t open, only the facial features move a little. This is shown in this video: https://youtu.be/CW2uw1bO73k
How can I export the model as a GLB with the shape keys working?
You just need to realise that whatever you use the GLB in needs to animate all the separate parts of the character together. Each shape key on each mesh and the bone movements all need to be animated independently.
The alternative is to export the character with the option “Convert skinned expressions to morphs” and / or “Mouth Open as Morph”. Which combines all the expression meshes into one object and bakes the bone movements directly into the expression shapes. Which should solve the immediate problem, but it means you can’t animate the head / eye bones directly any more.
It depends what you’re using it for, if that becomes a problem or not.