Plus, the sewer dragon, proton beams, Mini-Pufts, the art of transparency, and freezing the world.
When visual effects supervisor Geoffrey Baumann came on board Gil Kenan’s Ghostbusters: Frozen Empire, one of the earliest conversations he had with the director was about resurrecting the audience favorite character Slimer from the 1984 movie–in a very 1984 way.
“There was a strong desire for Slimer to be a puppet,” says Baumann. “Arjen Tuiten, our creature designer, helped manufacture Slimer with the original mold from the ’84 film. It was based off of the original Slimer puppet, and the desire was for Slimer to be puppetteered for the entire film. We didn’t quite end up there, but everything that ended as CG was based off of a puppeteered performance.”
A few different sized silicone puppets were built for puppeteering on stage with the actors, and then also against bluescreen. “For the attic scene where he is underneath a pile of trash,” recounts Baumann, “that was filmed on set. For shots of him eating the Cheetos, those were filmed on the bluescreen stage and composited in.”
“Some of them were replaced digitally, but at the end of the day, Gil wanted to make sure that if he looked at it, you’d be unable to identify between puppet or CG Slimer. It was a good litmus test for us to make sure we were true to puppeteering motion in CG. For example, what the jaw could do as it unhinged as a puppet could only be replicated like that in CG.”
The Slimer puppet was scanned by Clear Angle Studios in one of their photogrammetry booths. “One thing we did to check between them were witness camera range of motion tests with regards to just seeing how much the puppeteer could move the arms up and down, how the jaw opened, again to make sure that if we did go CG, we were staying within the constraints of the puppeteer and the puppet itself.”
Sony Pictures Imageworks was then responsible for building the 3D asset that matched the practical puppet. The studio also tackled the ghostly transparency of Slimer, something that back in 1984 was achieved via optical compositing on an optical printer (by Boss Film Studios).
When Baumann and the team looked into that from the original film, they soon realized that “we probably all have memories of what the ’84 look was, and there’s certain consistencies we may have in our mind that don’t actually hold true. With transparency, I think modern viewers respond much more positively to scene-based lighting than something that’s flatly lit in an environment. So we ended up shifting our CG Slimer to that. During the shoot we were thinking it would be self-illuminating, not scene lit. But then once we started compositing either the puppet or CG with more of a flat lit lighting pass, it didn’t marry to the scene as much. So we ended up shifting a little bit more towards scene lighting.”
“The other thing is, I am not usually a big fan of glows,” adds Baumann. “It’s something that often is just added on in comp just to get a little extra something out of it. But it was something I had to embrace on this project because Gil said, ‘It’s Ghostbusters. There’s glow.’ We did find our way eventually. Still, the opacity and glow was a challenge because Gil wanted to maintain detail and fidelity, but then the more glow we added or the more transparent something became, the less detail or fine edge detail we had in something.”
That challenge with the transparency held true for other ghosts in the film, as well, such as the sewer dragon and Melody. Baumann explains further: “The color of the sewer dragon or the color of Slimer would change depending on whether they were over a bright white window or a brick wall. I’d never dealt with as many translucent characters as this. Melody, similarly, when she was over a brick background, she became more magenta. Then when she was in the park, she looked a little different. The challenge was how to make it feel consistent across multiple scenes or within one scene as the backgrounds and the lighting changed.”
Enter, the sewer dragon
One of the major ghosts the Ghostbusters encounter in the film–and eventually take down via Ecto-1, their proton packs, an RC car and a flying drone–is the sewer dragon. It flies around New York streets as the group chase it in their vehicle.
“For that sequence,” describes Baumann, “we had the traditional second unit spending two and a half weeks in New York driving through the streets, shooting the action beats. Before that we had a week in London shooting car process work. The show is a bit different than other similar sequences I’ve done in the past where we did the process work upfront.”
At one point, Phoebe emerges from the car on a gunner seat. This was a rig on both the process car, situated on a motion base, and the practical car filmed in New York. “For the most part, the drone and the RC car were CG, but they were functioning props that were remote controlled and could be flown or driven on the street,” says Baumann.
The sewer dragon was a CG creature. It was originally designed by DNEG, and then ultimately crafted for the film by Imageworks. To stick to the 1984 homage, Baumann looked to the original film’s subway ghost for reference–“The transparency and color of that ghost was a great starting point.”
Baumann credits animation supervisor Troy Saliba with bringing a more classical animation feel to the sewer ghost, alongside the director. “Both Gil and Troy were very much into drawing on top of frames in order to give composition or motion curves with the animators. I think it was a really positive process for a lot of the younger animators to have more traditional animators like them giving direction with drawings rather than just words.”
During the sewer dragon chase, audiences get a close-up look at the Ghostbusters’ proton packs and fiery proton beams. Again, these were crafted by Imageworks with the intention of matching the look of the 1984 film. “The proton packs for the original Ghostbusters in our film were the original packs from ‘84, which was really cool,” highlights Baumann. “The beams themselves came from the build done in Afterlife. We started with that and then we wanted to improve upon it. There’s a lot of dynamic range within those streams that you can really see in the HDR version.”
Mini-Pufts are back
Frozen Empire sees the return of the Mini-Puft marshmallow characters, who get themselves into all kinds of gooey mess. Here, Baumann pays tribute to the work of visualization outfit The Third Floor for coming up with fun pieces of action in previs and postvis.
“Visualization supervisor Justin Summers and his team did a fantastic job of setting the stage for that. It was that, coupled with Gil’s ability for free hand drawing, for painting on frames to give the exact framing and kind of beats that he wanted. Then Troy Saliba was crucial in overseeing all the little vignettes of action those guys go through.
“Gil allowed Justin and his team to riff off of certain props that were in the space to allow them to have a little bit of say over the artistry,” continues Baumann. “On set, there were little maquettes, all the way from foam pieces to 3D printed models. Those were primarily used for focus and lighting reference.”
How to film a real live ghost
The ghost Melody who befriends Phoebe was one that had to closely interact with others in her scenes, a tricky prospect given she was also transparent and constantly bubbling with blue flames (owing to her death in a fire). However, as Baumann discusses, the director did not necessarily want to film her separately to accommodate those aspects of the effects.
“I think a lot of filmmakers now don’t want to sacrifice the ability for characters to perform with each other for the sake of visual effects and are willing to give us complications with regards to that, and there is something to be said from a performance standpoint, which I understand. We may have had one or two shots where they’re together that were of a motion control variety, and those were when it’s actually the Phoebe ghost when she’s in the lab. There’s a tracking shot right to left that we used a 15-foot Technodolly on, but everything else was moving, translating cameras that we had to recreate the backgrounds for based off of clean plates and then roto Melody out and put her back over the top.”
During filming of Melody scenes, a very deliberate keylight would be used to aid in her blue lighting. It would often then need to be painted out, along with anyone holding the light. “But other than that,” says Baumann, “Gil wanted it to be as if he was shooting any other scene. It was just that it was then later a lot of work in roto and comp and then FX sims for her fire.”
One of the significant scenes between Phoebe and Melody sees them playing chess in the park, with some of the chess moves happening ‘invisibly’. “That chess board was an SFX rig made by special effects supervisor John Van Der Pool,” states Baumann. “Pieces could move on their own with magnets with a little bit of cleanup from us on the board itself. Then we also built the chess board and all the chess pieces of CG assets so we could blend back and forth. It was really a hybrid of SFX work when Melody’s not there, for example, and then a CG chess piece put into Melody’s hand once we’ve created her transparency so that we can see the pieces that she’s occluding, and then sometimes a hand-off back to practical chess piece.”
Meet Garraka and the big freeze
At one point, the demonic god Garraka escapes from an orb he has been imprisoned within. “Gil wanted Garraka to be like a prosthetic,” advises Baumann. “He wanted it to have a texture that you might look at and say, ‘Oh, that looks like latex,’ or when the hands move, there’s a bit of stop-motion aspect to them. For reference, we ended up looking at Jason and the Argonauts and how Ray Harryhausen created animation back then.”
DNEG produced the concept for Garraka, with Imageworks handling the build and animation. “One of the challenges with him was not over-animating him,” notes Baumann. “We had to find a way for him to be foreboding because there’s not a lot of dialogue that comes from him. With his main power being icy breath, that also made it a bit of a challenge because wind is something that isn’t very visible, so we had to then compliment that with a complex package of FX work that came from him as well. He’s always shrouded in a bit of vapor that was based off of a dry ice look.”
Garraka freezes the city, resulting in a massive storm and ice growth, a mix of FX sims and large matte paintings by Imageworks. Here the main hurdle to climb, identifies Baumann, was the sense of scale. “You can get interesting effects as the ice crawls across a door, but then when you see that crawling across a building, it doesn’t always quite seem right. It can feel stop-motion-y or time lapse-y, and Gil did not like the first pass we had at that. We also struggled with the ice with regards to how much opacity it had. If you look at a bunch of reference of Northeastern United States into Canada where you have buildings covered in ice or bus stops and handrails that are just encompassed in this ice, those are generally very opaque and solid and you don’t necessarily see through it. But oddly enough, when we started to render things like that, it didn’t look like ice anymore. It looked like a big lump of white goo. So we really had to play with secularity and transparency and get some refraction in there to visually understand that it was ice.”
Retro VFX with a modern touch
Frozen Empire ultimately featured around 1400 visual effects shots, the bulk of which were crafted by Imageworks, with DNEG and Barnstom VFX also contributing (Nicole Rowley was the film’s visual effects producer). For Baumann, the film offered that rare chance of going back to the traditional days of special and visual effects, while also using the latest tools to bring a ton of characters and environments to life.
“That’s one of the things that I really enjoyed about the film was the fact that we had all of these cool old-school effects, the smoke getting pulled in and out of the door in the beginning–that’s all practical. And then there’s the remote control vacuum cleaner, remote control tricycle, and the puppets. I really enjoyed working with the puppeteers and special effects and giving them the chance to shine.”
You can also listen to our befores & afters podcast with Imageworks visual effects supervisor Jason Greenblum, below.
