Okay, I am not going to check back and see who wrote what, as this thread has gotten rather long, but rather just address some of the general points.
The uncanny valley exists, and will continue to be a problem until advances are made to overcome it. I also think that the advances will be a matter of TECHNIQUE rather than TECHNOLOGY. CG is an art form, and requires artists. Consider that a life cast of a human face often looks fake, while a sculpted one seems real. Let’s take a look at both these cases:
The fake-looking cast results from the subject reacting to the process of making the cast. Actors standing perfectly still while their faces are scanned by lasers are going to have a hard time keeping even a relaxed expression. Their acting will also be hampered by the unfamiliarity of tight, itchy mocap suits, or little reflectors stuck all over their faces. There are muscles in the face that very few of even the best actors have complete conscious control over. This, along with other related phenomena, explains the effectiveness of method acting. Actors working on a green screen often come across just as fake and stilted as CG humans. When actors first began to make the transition from live performance to film, they needed to unlearn a lot what they knew. Motion capture is another kind of performance yet, and we are starting to see specialists like Andy Serkis who do it particularly well. I think an actor looking to get into motion capture should try wearing the suits around all the time, until it feels natural. Otherwise, the capture data will reflect their unease in the suits.
The sculpture that looks real is made by a person who understands both the minutiae and the entirety of the human subject. I think the problem with a lot of inhabitants of the uncanny valley is that their creators were too focused on the details, and forgot to think about the whole. The benefit of exaggerated or fantastic characters is that the animators are freed to think about the characters in broader terms, and how the parts relate to the whole. When your goal is entirely to make a character photorealistic, it is easy to become focused on doing just that, and lose perspective of the character’s personality and place in the story. Sometimes a step back really helps, and when an FX company is behind schedule or over budget, that step back is the first thing to go.
One of the biggest problems is eyes. We are born with the instinct to respond to faces, and the eyes especially become a center of focus. Even cameras can recognize faces now! Some of the the common problems I have seen is eyes that are either too shiny or too dull, or are either too wide eyes or too sleepy looking (we are talking about a feature that can convey completely different expressions with changes of less than a millimeter). In real life, eyelids move up and down as the eyes look in different directions, and the lower lid pulls toward the center of the face when the eyes close. These are both things a lot of animators get wrong. The trickiest thing, I think, is that when we look around we use a combination of moving both our heads and our eyes. I’ve no idea if there are any “rules” for how much the head moves versus the eyes when we look around. It would be helpful to know.
CG really has come a long way in a short time. Think how many lifetimes it took the human race to progress from stick figures on cave walls to the ceiling of the Sistine Chapel. Looking at the advances made in our industry in just a few decades is really impressive. And unlike other advances in computer related fields, it is not entirely a matter of bigger and better software. As individuals and as a community, we artists are continuously pushing the boundaries. The uncanny valley is just one of those boundaries, and when it is crossed I don’t think it will be a result of a new technology, but of someone finding a better way to use the technology we already have.