Marvel Studios’ Guardians of the Galaxy Vol. 3, the final film in director/writer James Gunn’s trilogy about a beloved band of planet-hopping misfits, features action, comedy and chaotic weirdness.

To bring it all to life, Gunn and his franchise VFX supervisor, Stephane Ceretti, oversaw over 3,000 visual effects shots created by a raft of companies including Weta FX, which was responsible for the final battle sequence; Framestore; ILM; Sony Imageworks; Rodeo; and Crafty Apes.

Heading up the Weta team was VFX supervisor Guy Williams, who previously collaborated with Gunn on Guardians of the Galaxy Vol. 2, for which Williams was Oscar-nominated, and the HBO/Max series Peacemaker and The Suicide Squad. Weta created almost 700 VFX shots for this one.

Williams joined Weta in 1999 to work on Peter Jackson’s The Lord of the Rings trilogy. His credits include Avatar, Iron Man 3 and The Avengers. I spoke with Williams about creating all the VFX and the challenges involved.

What were the big challenges of this job?The main things we had to deal with were significant amounts of destruction work and a large-scale build. Right from the start, we knew creating the Arête spaceship was going to be very challenging — not just visually challenging as a very complex build, but also esoterically, as the whole idea is that it first appears as a 300-meter-high skyscraper on Counter Earth before it emerges to reveal it is actually 3 kilometers — over 2 miles — wide. So every time you see it, you want to lean into the idea of its size and scale.

But it’s not just a huge spaceship. It’s damn near a piece of art. It’s beautiful, with cubes upon cubes with interesting right angles. It’s almost brutalist in a way, but it’s also covered in thousands of panesof red, rubylike glass. On top of all that, we had to do tons of destruction as the ship rises up out of a harbor, ripping up the ground and the ocean and then flying off into space.

Next, we had the big battle scene, where the ship is slowly being destroyed. It breaks up over the course of a couple of dozen shots, and you’re trying to create explosions on an object that’s 3 kilometers across and make them look realistic on that scale. It was a bit of a layer cake in that sense. Weta also did the Abilisk pit sequence, where three of our heroes are separated and locked in a cage with the Abilisk.

How tough were the water and battle VFX scenes to do?The water was one heck of a challenge, and so was the battle onboard the Arête, where we had 18 shots stitched together into one seamless 2.5-minute action shot. James is a very thoughtful director when he’s shooting scenes. He’s always thinking two steps ahead, so that was shot brilliantly, but it was still always going to be a very hard shot to do. Then there was all the other work we had to do to fill in the gaps and create all the Arête’s other subenvironments, including the space port, pilot bay, command deck and the hall where the fight takes place.

How did you build the surrounding city scenes?We have various CityBuilders, and we used a CityBuilder-like approach to procedurally generate the layout and dressing for about 24 square miles — almost the surface area of a city — on the Arête’s structure. We also built an entire city surrounding the Arête that was loosely based on Seattle, with a large harbor, a downtown and waterfront district, and an island office park surrounding the ship, complete with large-scale waterfalls.

We built what we called Counter Earth, and then for the city, we built Counter Seattle, so called because the film’s VFX supervisor, Stephane Ceretti, was so helpful to us in so many ways — one of which was that he shot beautiful aerial plates of Seattle for us. Ideally, we would have just been able to use those plates and augment them, but of course once you’re into shot design, you end up not using a single plate. But they became perfect references for our purposes.

It’s the same harbor as Seattle’s, but the rest of the shoreline was modified rather heavily for our uses. We got rid of the iconic buildings, and James also wanted it to look like a brutalist concrete version of the ‘70s architecture, so for a lot of the downtown buildings, we pulled out all the glass and replaced it with concrete to create large, megalithic structures. It’s a nice dichotomy between the harsh concrete city and the beauty of the harbor.

Did you do any character work?Yes, we did a lot of shots on Rocket and Groot, and we also did a lot of digidouble work. Often, we replaced Peter Quill (Chris Pratt) and Nebula (Karen Gillan). because what we needed them to build or do was more than they could do.

We worked closely with Framestore and the other VFX houses on all the character work. Animation supervisor Mike Cozens really got inside of what had been established in the first two movies and what Framestore had established for this one. For instance, we had an interesting fight sequence up in the command deck where Groot had smuggled a bunch of guns onto the ship. He kept eight of them, so we had to create eight extra arms.

Tell us about the pipeline and the tools and technology you used.In terms of our animation pipeline, every time we see Groot, he’s doing something that we haven’t seen him do before. Like in the end tags, he’s now what we call “The Alpha Group.” The animation team used a lot of existing tools and refined a lot of tools. If the arms had to be done a certain way, that’s what we did.

We could have built a very complex octo-Groot with eight arms for the whole movie, but it just wasn’t worth it, so we came up with ways to make it work for just that little section. We made a hollowed-out torso version of Groot that had arms that could just fold up. That way, we could just plug in to that torso instead of carrying the rest of the stuff all the time. Even in that scene, Groot takes two of his arms and turns them into a big wicker shield so that Quill is protected, and we had to do all sorts of things with the puppet.

All the destruction work was kind of straightforward but also challenging, as we had a lot of explosion sims, fire sims, fracture and shatter sims with redundant fracturing. The challenge was the sheer scope of it. You’re dealing with hundreds of explosions that are kilometers across. All the water stuff with the Arête lifting out of the ocean took six months to do. When you first see the spaceship, it’s about 1.5 kilometers across, which is a huge amount of water being displaced. Water sims are hard at the best of times, and on this one, we were trying to hold onto the scale as well. That’s the thing that makes water sims so hard. When it’s the size of a box, you have to break it all up into smaller sims and then stitch it back together.

We rewrote our CityBuilder program and created a new ruleset for it. We wanted to have a simple model, and it wasn’t just the CityBuilder we used for the Arête. There’s so much detail, with pipes and trenches and a sci-fi version of an AC unit all ranging up to large buildings on the ship. We had to lay all of that onto an existing surface and write a lot of new tools to do it. On top of that, once we built it all, we had to tell it where we wanted the glass because we wanted to build stuff under the glass, but it couldn’t stick out too far or it would intersect with the glass. So essentially, we used a bespoke Arête-builder, if you will.

How many VFX shots did Weta do? And how long did it take to complete them all?We started working on it at the end of 2021, and it took us a good 14 months or so to finish it all. We worked very closely with Stephane Ceretti, and he and his VFX producer did a great job of identifying all the challenges ahead of them and being very realistic about it. They engaged with all the vendors as early as possible to make sure we all had the best chance of doing our best work on schedule. It was really refreshing that they were so proactive about it. In the end, we did almost 700 shots, and we had a team of between 300 and 400 on the job at any one time. It’s definitely one of the most challenging and interesting jobs I’ve ever done.