That explains a lot to me. The actors need those visual cues, and it shows through in the final product. It was a great result. I look forward to improved acting as this tech makes its way into other works.
Unreal Engine is also used by the BBC to create virtual studios for football punditry programmes. This uses a simpler green screen technology, but it demonstrates how Epic are moving away from their gaming roots.
https://www.youtube.com/watch?v=gUnxzVOs3rk