Hollywood special effects aren’t just about CGI — there’s still a world of creatures, props, and animatronics making movies feel real. Lately, more filmmakers are swinging back to practical effects. At Studio Gillis in Los Angeles, they’ve been at it for over 30 years, working on films like Alien and Predator franchises, Tremors, Jumanji, Prey, Once Upon a Time in Hollywood or Jurassic World: Fallen Kingdom. And 3D printing? It’s become their go-to helper. Here’s a behind-the-scenes peek at how they use it to turn ideas into movie magic.

Studio Gillis got its start over three decades ago with the legendary Alec Gillis, one of its founders, and has been building practical effects ever since — think creatures and moving models for some of your favorite films. While they still rely on hands-on techniques, 3D printing adds a positive twist. Sara Villareal, a special effects creator who runs their 3D printing production, showed us how it’s speeding up their work on projects like Alien: Romulus.

We sipped coffee in their meeting room, a life-size Predator next to us, an Alien queen bust on the wall, and the original Alien egg under the table. A big Cootie figure from I’m a Virgo peeked down at us. The workshop’s a different scene: benches for mechanics, electronics, and post-production, littered with half-finished projects. Something wild sat in the corner… But NDA stuff, so mum’s the word! Their 3D lab’s right by the workbenches, keeping the workflow smooth.

Making Custom Mechanisms

“3D printing makes my job a lot easier,” Sara says. “Before, animatronic parts took forever — someone had to mill or lathe each piece, test it, and usually redo it a couple of times. Now, with digital designs and quick prototyping, we skip all that waiting.” She shows us a monkey model, its face moving like the real thing. “Underneath, there’s a remote-controlled mechanism,” she says. “The old version was done the old way – glass, plastic, and metal, all tricky to fix. This 3D-printed one’s simpler to tweak or repair.”

Next, she pulls out the Alien chestburster — complete with a “baby alien” attached. “It’s the same setup we used in Prey,” she says. “Nylon-printed disks and wires — push and pull the sticks, and it slithers like a snake. We call it the tentacle mechanism; it’s in lots of creatures. There’s a head version too, for scenes where you can’t get close.”

With two sticks, that little Alien twists and bends, making incredible moves – just like when he came out of poor Kane in the first movie…
For Alien: Romulus, practical effects were key. “Fede Alvarez wanted that hands-on feel, like the first Alien,” Sara says. “We printed spaceship miniatures, the chest-burster, and a few props. Shooting with miniatures is fun, and fans still love it.”

As an example, she hands us a grenade — a Predator prop from Prey. “Printed and painted,” she says. “Quick, cheap, easy. We’re also printing wounds, props — tons of stuff. It opens up all kinds of possibilities.”

But that’s just a fraction of what Studio Gillis can do. Sadly (for you, readers) most of it is under strict NDA.

Post-Production Polish

Post-production is crucial for realism, and it varies widely based on project scope and deadlines. “Sometimes we print basic structures and pass them to sculptors and painters,” Sara notes. “Other times, prints go straight from the print bed to the paint shop, speeding up production dramatically.”

Some jobs come with lists of 50 to 100 parts and it’s up to Sara to figure out: pretty or fast? Sculpted over or standalone?

Tech Catching Up

3D printing is great for saving things from past projects — like latex masks or molds that wear out fast. “It keeps them around longer,” Sara notes. Combined with 3D scanning, it has significantly improved the once risky and uncomfortable lifecasting process.

“Not every actor can drop by,” she says. “We scan them wherever, print exact copies, and it fits — every time.” Or they can get a scan of an actor half the world away. No problem in a digital era.

Sara chuckles, remembering a lifecast flop: “Björk didn’t say she’s claustrophobic. Silicone went on, and she panicked — ‘I need my music!’ Kicking, screaming — we pulled her out.”

Hollywood studios are starting to appreciate the benefits of 3D printing. “Some folks pushed back on tech like CGI or printing at first,” Sara says, “but it’s handy for big batches—armor, molds, whatever — it works. And it’s only going to grow.”

Inside the 3D Lab

Studio Gillis has all sorts of tools, but for 3D printing, it’s mostly Original Prusa machines. “We’ve got MK4S printers — some new, some through the upgrade path all the way from MK3 — and XLs with five toolheads,” Sara says. “They’re absolute workhorses, not a day’s rest for them.”

And why Prusa? “They just work,” she shrugs. “No spaghetti surprises before a client shows up. Tight deadlines? No problem. Print quality is great, and support’s there if I mess up.”

Sara utilizes all sorts of printing materials — PLA, PETG, ASA, TPU, nylon… The XL’s multi-tool setup got Sara experimenting with true multi-material printing. “We’re mixing stuff in one print — TPU with PLA supports that pop off, or water-soluble filament for clean tubes,” she says. “No more splitting big parts. It’s changing how I’ve done this for 10 years. And the toolchanger is  perfect for mechanical heads.”

Be like Sara — do your projects!

Sara began her 3D printing journey in 2017 with a basic RepRap kit. “Wooden base, endless leveling… I was over it,” she laughs.

Quickly frustrated, she upgraded to an Original Prusa MK2.

“Building the MK2 kit taught me how printers tick. That was invaluable to my career,” she says. “Most folks buy one, use it, and stall when it breaks. Not me—I’ve got it covered.”

Today, she can give advice to those who want to get into the movie industry.

“Make your own stuff — props, cosplay, anything,” she says. “Share it online, email shops like us. We need creative people.”

And one more thing she adds: “Get a 3D printer. It’s a standard now and it unlocks so much.”

Who’d argue with that?

Jakub Kmošek, Štepán Feik and Tanya Nedeva