Staging the Final Battle
Karen Moltenbrey
June 14, 2019

Staging the Final Battle

Avengers: Endgame is filled with many impressive visual effects sequences, none more than the end battle, which brings back a plethora of characters who join in the fight to defeat Thanos. After the Avengers return to present day with the Infinity Stones, the stones are inserted into a gauntlet created by Tony Stark, and Bruce Banner uses it to bring back all those who had disintegrated from Thanos’s snap. But, the past version of Thanos arrives and attacks the compound with his warship. Soon the restored Avengers and other heroes arrive, and a battle of epic proportions ensues. Various heroes step in for the relay to carry the gauntlet to safety, with Thanos gaining control at one point, but not before Stark steals the stones and uses them to disintegrate Thanos.

“Going back to Civil War, we had about a dozen heroes running at each other and fighting in the big battle scene. In this one, we had hundreds of heroes and villains, and every Avenger using his or her powers at the same time. The complexity of the shots went through the roof!” says Dan DeLeeuw, Endgame’s visual effects supervisor. “When we started the show and read the script, we thought, OK, there are a lot more character moments in the film and we wouldn’t have quite as much to do in the early part. But, there were visual effects running through the entire beginning of the film. And then once we got to the final battle, there were showcase effects – and lots of them. It was kind of the kitchen sink, with everything in the kitchen sink.”

The big challenge in the sequence comes from the sheer number of digital characters and blending them with the live-action characters. “It’s something that really should have broken the back of the entire studio in terms of getting it out, but Weta Digital and ILM really pulled it together and got it done,” says DeLeeuw.

The battle starts when the Avengers’ compound is blown up. Weta built, and then destroyed, the CG environment, making sure set pieces could be moved to accommodate various camera angles. Weta also built digital doubles of all the characters and all the creatures – essentially a kit they used to create the battle. Then, the fighting breaks out within the crater that’s now where the compound used to be. 

A lot of the sequence was shot in Atlanta on a soundstage. “One of the biggest challenges was just trying to get the lighting to work in a way that was believable,” DeLeeuw says. “And, no matter how big the stage was, it was never big enough to photograph all the action. Whenever we tried to put set dressing out, it would interfere with the sheer number of stunt characters we had to photograph. Imagine trying to have maybe 40 stunt people out there, spread out. They’re sorcerers and Asgardians, all in costume, and between them all, you know you have to have your CG characters interacting as well.”

As DeLeeuw points out, the Sakaarans from Guardians were actors, dressed in black armor. The Chitauri were CG, as were the Outriders from the first Avengers and Infinity War. “You are on the stage, and there’s dirt on the floor, and set dressing, with stunt people swinging through the air. That’s where we started the battle,” he says. “Then the CG has to carry that all the way to what you actually see in the film, where the battlefield is populated and extends for miles beyond what you’re actually photographing. You’ve got the fog of war and the light effects, and everything else, so you’re starting with very little and adding to it. In some cases, making the shots all-CG might have been easier. You don’t get the nice interactivity that you do with stunt people out there, but just being able to control the scene from the beginning sometimes would have been a more expedient route.”

The final battle is filled with explosions, starting with the compound and continuing as Captain Marvel (ILM, to be exact) destroys Thanos’s ship – all calling for large-scale simulations. “We wanted to push the envelope on that type of shot. In Winter Soldier, when the Helicarrier falls into the river – we wanted to push that look and those effects further,” says DeLeeuw, noting the battle scene in Endgame was an extension of that as well as the airport battle in Civil War. “The water sims and explosion sims [in Endgame] are light-years ahead of where we were just six, seven years ago in terms of what we were able to do.”

This time, however, there was little to no pre-production time to plan out the sequence, since this film was shot back-to-back with Infinity War. “Our pre-production time was occurring while we were shooting and also posting Infinity War, so we had a previs team going for Endgame and a postvis team going on Infinity War – around 60 people from The Third Floor working on both films at the same time,” says DeLeeuw. “So, we took the final battle and just ran with it, always trying to give a little bit more.” 

Make no mistake, visual effects carried this major battle. And in the thick of it all were two vendors in particular: Weta and ILM. Weta’s first shot in the film is in the third act when Thanos destroys the compound, and culminates when Stark succumbs to his injuries.

While the set was extensively dressed with a mixture of building rubble and burned-out tree stumps (the compound exists on the edge of the Hudson River surrounded by forest), when the sequences were cut together, the tree stumps played dominant, making it feel as if the battle was taking place in a bombed-out forest. So, Weta artists roto’d all the characters off the plates and replaced the set environment with a CG version that had more rubble and chunks of concrete and building, and “checked” the forest a bit.

“Predominantly, the environment is CG throughout the sequence, and that turned out to be a blessing. It’s a little extra work to get to that point, but once we were in that space, we could relight the environment and are not constrained by the lighting they got on set,” says Matt Aitken, VFX supervisor at Weta. “We can make it feel more like we are outside, with low lighting from a distant sun, and we can change the look of the environmental lighting from action beat to action beat. So, it’s sunny at the start of the sequence, and then after the compound is destroyed, it’s overcast; there’s a huge pall of smoke and dust hanging over the area. And when the portals open up, it becomes brighter again because we’re playing the environment lighting to match the mood of the film.”

For the explosions, Weta extended the work it did in War for the Planet of the Apes for the destruction of the base at the end of the film, incorporating volumetric pyro physics and modeling the transfer of heat into its simulations for a more physically correct and realistic result.

Weta also employed its crowd simulation software, Massive, developed originally for The Lord of the Rings, to populate battle scenes with tens of thousands of soldiers. “There were a lot of CG shots that required camera animation,” says Aitken. “There’s a shot when the two armies clash with each other at the start of the battle. It’s a big complex shot, and it lasts for quite a while. It’s one of the longest shots we produced. There are plate elements in the shots, but essentially it’s a CG shot that easily could have gotten muddled. Instead, our animation team on that shot produced something that is spectacular and also very easy to watch. You know where you’re supposed to be looking at any one time. That’s a real art.”