The Tech Behind the Visual Effects of World War Z

Summary

In this article, we explore the technology behind the visual effects of the blockbuster film World War Z. The Moving Picture Company (MPC), one of London’s top visual effects companies, used their in-house program, ALICE, to create intelligent agents that were programmed with a form of AI to interact and create swarming zombies. MPC worked on many sequences in the film, including the largest one set in Jerusalem, Israel, which was shot in Malta. The biggest challenge to this scene was the large zombie crowd shot, which was built from photo references and motion capture performances.

Introduction
The Swarming Zombies
The Israel Sequence
The Complex Crowd Shots
Conclusion

The Swarming Zombies

To create the swarming zombies, MPC used their in-house program, ALICE, which allowed the agents to avoid bumping into each other. However, for the film, the zombies needed to climb all over each other, so MPC had to modify the program. The zombies were not animated by hand but were intelligent agents programmed with a form of AI that allowed them to interact.

The Israel Sequence

The Israel sequence was shot in Malta, and the biggest challenge was the large zombie crowd shot. MPC’s environment team built a large wall that surrounds Jerusalem, and the zombies climb over it. They also built a large CG environment outside the wall with wasteland and a backdrop showing Jerusalem. Early on, they received concept work showing the different shapes the crowd could take. For the pyramid shot, they defined the shape and layout the crowd could take and populated it with motion capture clips. The largest pyramid shot was made up of around 5,000 zombies.

The Complex Crowd Shots

For the complex crowd shots, MPC used various different motion capture clips, including performers running up a ramp and jumping off from the height of the bus. The digital zombies come from a database built of motion capture performances, which are then randomized with a core set of attributes. Each of the intelligent agents in ALICE effectively has a mind of their own. They act by being given an objective, a set of rules to achieve it, and then a simulation is run. Even the MPC artists have no idea exactly whether or not they’ll succeed when they start it.

Conclusion

MPC’s use of their in-house program, ALICE, allowed them to create intelligent agents that were programmed with a form of AI to interact and create swarming zombies for the film World War Z. The Israel sequence was shot in Malta, and the biggest challenge was the large zombie crowd shot, which was built from photo references and motion capture performances. MPC used various different motion capture clips and randomized them with a core set of attributes to create thousands of different zombies. The use of ALICE made it easy for the different departments to work together and create photorealistic lighting on every single shot.