Why was it so hard?



We had to do the whole film as an animation first. We edited that animation, even with sound, just to make sure the timing worked with the sound effects and music. And once we were happy with it, we had to do the lighting in the animation as well. Then all that animation translated to actual camera moves and positions for the lighting and actors. We did a whole exploration of the screenplay, every single moment; we made judgments about everything. Once we began shooting, we were constrained by the limitations of that programming.



How so?



We shot space scenes in a sort of virtual-reality box that had the characters’ environments projected on the walls. The actors had very little room to change their timing or their positions. But we adapted. Sandra Bullock trained like crazy to be able to be a part of all these technological challenges. It was choreography for her. I think her background as a dancer helped a lot. It was so much by numbers. After all the training and all the rehearsals, she was able to just focus on the emotional aspect of her performance.



How long did it take altogether?



We animated for two, maybe two and a half years before we started shooting the actors. Then we shot the film—and then the poor animators had to start from scratch because they had to base their final animations on what was shot. Someone suggested we just call Gravity animation, but I don’t think we can because there’s a fair amount of live action. And it was really hard work for the animators. After all, you learn how to draw based on two main elements: horizons and weight.



And you had neither!



Exactly. They had neither of those things, poor guys. It was a nightmare for them. They would make stuff and I’d say, “Yeah, but that looks like they’re standing at a bar, not floating in space.” We had a physicist explain the laws of zero gravity and zero resistance. After three months, the animators really got the concept and it started to become second nature. You could always identify the new animator on the block because he’d be the guy having panic attacks and a nervous breakdown, wanting to quit.