Here's a great interview with Max Solomon who was our Animation Supervisor on Gravity.
VFX Supe Tim Webber on the Challenges of Gravity
Three to four years is like a schedule for an animated feature.
It is. And in many ways, this is like an animated film.
In fact, four Framestore artists received VES nominations for Best Animated Character in a Feature Film — for the astronaut Ryan played by Sandra Bullock (nominated for an Oscar for Best Actress).
We consulted with the VES to see if this character counted as an animated character. She’s the main character in the movie. Apart from her face, for most of the movie she is an animated character. And sometimes, even the face is an animated CG character. There is much more screen time of animation for this character than any other character nominated. So it counts as an animated character.
Did you use performance capture?
We couldn’t use performance capture. The character is pretty much all keyframe animation. She’s guided by [Sandra Bullock’s] performance, but not her movement. A lot of the guides for animation came from her face. Because what she was doing was in the world of gravity and she didn’t have the various elements around her, her body performance couldn’t give us the right physical movement. We used video as reference and we did put markers on her to make the video nice and clear, but I don’t think we ever tracked her body properly apart from a few moments for technical reasons. While they were filming her face with the main camera, we had video cameras on her body so we had as much reference as possible.
Did you ever consider doing this as an animated feature?
There’s something different about having a human performance. CG still can’t do humans absolutely believably. And this was a movie that had to not feel animated. It had to feel absolutely real. It’s a contemporary thriller, not a fantasy in any way. We had to not only do the CG, we had to make it feel 100 percent real.