How practical and digital effects combined to make the murderous A.I. toy in ‘M3GAN’.
When early trailers for director Gerard Johnstone’s M3GAN were released, viewers quickly speculated whether the titular A.I toy-slash-doll-slash-family companion robot had been brought to life as a practical creation, or via CG, or with digital enhancements.
It turns out, it was all of the above, as can often be the case with the best character visual effects work. Full scale practical on-set make-up and animatronic effects for the M3GAN robot were handled by Morot FX Studios (Weta Workshop also contributed to the film), with an on-set actor, Amie Donald, performing in a special mask and costume.
Fin Design + Effects worked for over 18 months closely with the set, production and stunt designers on nailing that ‘creepy realism’ that Gerard envisioned.
The Fin team, VFX producer Emily Higgins, CG Supervisor Phil Sloggett and compositing supervisor Rick van de Schootbrugge, worked on over 550 shots which involved all the visual effects disciplines.
Significant efforts involved the intricate enhancements to the central character M3GAN, often for the purpose of aligning the slightly different looks of Donald in mask and the practical animatronic and puppets used during filming.
A fully CG version of M3GAN was also realized for the climactic and frenetic fight scene and–spoiler alert–her ultimate demise at the hands of another robot, Bruce (also a mix of practical and CG effects).
Here, Fin CG supervisor Phil Sloggett and compositing supervisor Rick van de Schootbrugge tell befores & afters what went into the creation of M3GAN, from the facial precision, to the tailoring of her CG dress, and to her complex inner mechanics. They also discuss the many invisible effects in the film, one of the toughest of which turned out to be…a CG toolbox.
The nature of M3GAN enhancements
Fin was consulted right from the outset as creative partners working closely with director Gerard Johnstone and Blumhouse and Atomic Monsters Productions, in all creative conversations to achieve the ‘almost real’ feel of M3GAN.
During filming, on-set visual effects supervisor Steve Vojkovic oversaw scenes that would require visual effects enhancements for the two key robot characters (Visual effects supervisor Jonathan Dearing worked at Fin overseeing the final VFX work). One robot character was M3GAN, the main robot who is paired with the young Cady (Violet McGraw) by her roboticist aunty Gemma (Allison Williams). Another was Bruce, the larger, slightly more old school robot from earlier in Gemma’s career. While Bruce’s on-set animatronic capabilities were somewhat rudimentary, M3GAN’s were significantly more complex.

There were three different on set versions of M3GAN which needed to be ‘blended’ for reality and consistency. “There was the ‘main’ M3GAN , an animatronic, which had full internal facial rigging with actuators at the corners of the mouth, under the eyelids and the eyebrows,” explains Phil Sloggett. “We treated the animatronic face as our hero version. Then there was a silicone mask worn by Amie Donald for all full movement scenes, which had big eye and nose holes cut so she could see and breathe. Plus a few other pole-rigged M3GAN puppets were used to film limited movement or torso shots.”
These different forms of M3GAN and performance techniques presented a challenge to the visual effects team, as Rick van de Schootbrugge observes. “The different types of puppets used, plus re-creating a fully CG M3GAN, and achieving consistency between them–which one is the truth?–that was probably the longest ongoing challenge of the film in getting this likeness right.”
In order to deal with that hurdle, Fin started with a Lidar scan of the Morot FX M3GAN puppet and began replicating skin, eyes, hair and the interior mechanics. “We had what we felt was a very accurate digital representation of the face,” says Sloggett. “We retopologized that perfectly, even with our rigging approach by matching exactly where those actuators were on the internals.”
One particular aspect of the M3GAN build that Fin focussed on was the robot doll’s dress, setting up a cloth pipeline for it to feel real. Starting with a Lidar scan, and also armed with actual dress patterns provided by production, the team began modeling a CG dress to match the practical on-set one for simulation and be layered over the 3D M3GAN.

Sloggett explains. “Funnily, when we asked for the patterns we expected to be sent an Illustrator template, but we actually got a giant cardboard box with genuine fabric swatches and the physical patterns that the tailors had used. We laid those out and did some photogrammetry, traced and stitched them together in Marvelous Designer.”
Ultimately, shots of M3GAN would be the result of a combination of all techniques, from practical to digital. In many cases, Fin would need to make fine adjustments to the animatronic or mask for enhanced expression. But there would always be, as van de Schootbrugge identifies, a ground truth emanating from what was built.
“We’d have reference plates where they put the doll into frame and then we’d go back and meticulously compare that with our CG renders and then finetune the renders in comp accordingly to get a seamless match–making sure that the dress, skin and hair looked the same. It came out pretty close directly from CG, but then we’d have to push the last 10% around to make sure it sits in perfectly with all the black levels, the grain, and then plus it up with environment atmospherics, as well. It was just about making sure that all gels together and tells the story credibly.”
When things get crazier
Towards the end of the film, M3GAN is under threat and fights back against those narrowing in on her erratic behavior. This culminates, initially, in Gemma attacking the doll and sawing into its face with a hedge trimmer.

“They actually managed to do a lot of that scene in-camera,” observes Sloggett. “Allison Williams was holding and swinging a large foam object [the hedge trimmer] around in front of the younger actress. But the actual strike–when she connects with M3GAN’s face–was done with a puppet.”
There were added sparks and some animated blades, as well as an eye replacement for that shot. Adds van de Schootbrugge: “It was enhanced in comp, putting an eye back in and slightly animating the tear opening in the couple of frames. The sparks on top of it with smoke and flashes suddenly made it way more violent than what was shot on set. It was an effective combination of effects with the on-set puppet and clever editing.”
Then, M3GAN and Bruce the robot (controlled by Cady) engage in a killer showdown, done in CG. The final sequence was made up of an initial shoot and then additional photography some time later as the fight was revised in the edit. Fin contributed previs for key beats.
Filming that scene involved a combination of animatronic Bruce and a stand-in performer clad in a greenscreen costume performing the role of the bigger robot. This necessitated significant clean-up work in visual effects.
“It was very challenging,” notes van de Schootbrugge. “We had to paint out the performer who was intertwined into the plate. There’d be stuff going over him when M3GAN gets smashed onto the table and sometimes M3GAN is actually ‘folded’ around him. We had clean plates for that, but it was essentially a meticulous clean-up effort.
Bruce, remote controlled by Cady, eventually rips M3GAN in half. Fin achieved this as a CG rip, with some interesting conversations emerging about the kinds of mechanical pieces that would be inside the doll.
“We talked a lot about what fluid would be in there,” recalls Sloggett. “We questioned, ‘What comes out of M3GAN as she’s torn in half?’ That ended up being largely added detail from CG and comp, together with some fluid sims.”
The ripping shot is also close to the camera, right up on the digital dress which Fin crafted. Originally, the studio looked to the practical torn dress and doll reference, since it was in two halves, but then soon realized that the reference was too ‘neat’. Instead, Fin would simulate the effect.

Sloggett explains: “We wondered, ‘How do we make this jagged edge that doesn’t really follow the seam lines of the dress?’ Using the material swatches, we played with light behind and through the fabric, simulating internal sparks and explosions. We were able to get pretty good references to that, which created fantastic results.”
Seemingly coming back to life, M3GAN’s half body goes on the attack. Her ‘mask’ face is uncovered to reveal a visor and her inner head mechanics (something that was also fashioned as a physical prop). On set, a performer in a green head covering carried out the stunt work as the doll’s attacks continued, until Cady finally took out her robot with a screwdriver.
The visual effects crew modeled the faceless head in CG based on the practical reference and adding to what they had already built for the fully digital M3GAN model. “We took our beauty model and then just ripped her up and started putting in the extra pieces,” comments Sloggett. “We had some CAD reference for our artists to model the whole lot saying ‘Go nuts, in making this look exactly like that.’ We were then able to retrofit some of those pieces back into our scarred model as well, making sure we had the right stuff present underneath the scar.”
The surprising invisible effects challenge: a CG toolbox
There were countless invisible effects, including added trees, the ‘forgotten piano’, set extensions due to a re-shoot in different locations, GG shelving in the garage, and removing F-bombs and excess blood when the film was toned down from a R to a PG rating. And amidst the complex CG robot and digital enhancement work in the film, it turns out one of the most unexpected visual effects challenges was a largely invisible effects element required for continuity: a toolbox.
“There’s a series of three shots where Allison’s character shoves the table out of the way with a toolbox on it, which goes flying,” outlines Sloggett. “In the edit, there was one shot right before that moment featuring the big toolbox on the table, but then in the three subsequent shots it’s not there! This was a big continuity bug bear for the filmmakers who really needed that toolbox for those shots.”
Fin then set to work on modeling a detailed replica CG toolbox and tools, says Sloggett. “There were plenty of animation notes on how it should be flying off the table. I see that as a pretty remarkable invisible effect because it’s not the thing you would ordinarily notice, ‘Why on earth is there be a CG toolbox?’”