In the talk, Chahi and programmer Ronan Bel talked about the difficult, two-year iterative process of creating a dynamic world simulation that continues to change even when you're not looking at it. "At first, I thought only part of the world could be dynamic. For instance, a river would only be processed where it's running," Chahi said. But Bel outlined how a series of optimizations allow the complex interactions of rock, sand, vegetation, water and lava to operate at a consistent 30 frames per second on the Xbox 360, PS3 and PC. "Today, computers excel in brute-force computation, so it's better to compute the whole world – no matter what is happening, the frame rate remains the same. This is very important," Chahi said.
While Chahi's talk was light on details of how the actual game you play in this world would work, his infectious enthusiasm for the world-building potential on display has us eager to see more at Gamescom later this week.