Have to catch up after an entire week of sickness on bed . . . Here are some tutorials I studied some time ago which I would recommend.
- Character Facial Rigging with Judd Simantov
http://workshops.cgsociety.org/courseinfo.php?id=314
His joint based method is quite straight forward actually. The result is great if you are both a great modeler and rigger. You need to have beautiful topology and accurate joint placements. You can have some nice sliding effect by rotating the joints. But I’m afraid I will need much more time back and forth painting weight and hitting desired facial shapes.
- Expressive Facial Rigging by Josh Sobel
http://www.joshrigs.com/#!expressive-facial-rigging/cl5g
I bought a copy of Kayla for study without much hesitation. The price is reasonable and she has nice appeal. The setup is quite different from AM Stewart but I haven’t got time to break it yet. His tutorials of facial setup is easy to follow too. It is enjoying to watch and the steps are very precise. Facial rigging seems to be easier than imagine.
- Fundamentals of Animation Course by Aaron Blaise
https://creatureartteacher.com/product/fundamentals-of-animation/
I can’t stress more how every principal in traditional animation is exciting to me. It’s always admiring to see great animators like Aaron work.