Because the tools needed to film Gravity in exactly the way director Alfonso Cuaron envisaged didn't actually exist, the visual artists at Framestore effects house literally made new ones. These included a 3D scanner that creates models by taking 360-degree photos of an actor, and inventive new lighting solutions.
Two more fun Gravity facts for you: 1. A team of 40 people worked on only simulations of cloth for over a year to make sure the space suits looked right. And 2. If the filmmakers wanted to render the entire film on just on machine, they'd have had to start it in 5000 BC for it to be ready today.