For weeks, Finn Ross had been tinkering with one of the most important elements of “Frozen,” then a Broadway-bound musical with a tryout run in Denver. Those seated for the initial preview performance back in 2017 surely adored the Disney movie; they knew every lyric, every character, every line. At that point, could anything about this story surprise them?

It was time to find out. Onstage, Anna lost her cool. Chaos ruined the coronation party. Elsa charged across the room, and just as she crashed into a wall, ice seemed to sprout from her bare hand, spreading all the way around the proscenium, crawling across the floor and covering every visible surface of the stage. Within 16 bars of music, the entire kingdom of Arendelle had frozen over.

Elsa collapsed in exhaustion and shock, but the audience gasped in delightful surprise, applauding as they marveled at the magical transformation.

“We worked very hard to earn that applause and be worthy of it,” Ross told The Times. “It was difficult to nail the timing of the music and the effects perfectly, getting the whole thing to be fluid and dynamic and work in terms of the spatial relationship of everything. So when I heard their reaction to it, I felt quite excited. I thought, ‘Wow, we found something that has the potential to be one of those lovely moments the audience remembers and takes home with them.’ ”

(Disney)

That enchanted bit is just the tip of the iceberg that is projection design, a longstanding stage specialty that often goes unrecognized. It’s not traditional scenic design or lighting design; it’s not always splashy animation that’s given a moment for applause. It’s a separate artistic discipline that comes in many forms, is evolving fast and becoming exponentially more prevalent — on Broadway, on the road and in regional theaters nationwide.

“It’s never about putting the technology on display or having as many projectors as you can fit into the building,” said Ross, who also worked on the spellbinding visuals of “Harry Potter and the Cursed Child.”

“It’s about having a good idea to give those projectors something interesting and special to do that’s part of a bigger picture, one that includes the actors, the lighting, the costumes, the music, the scenery, the props, the special effects,” he said. “I’m not interested in the audience thinking, ‘Oh gosh, he’s terribly clever.’ I’m interested in them thinking, ‘Wow, the total experience we’ve had this evening of everything has been wonderful.’ ”

Like the visceral magic in “Frozen,” which will start a two-month run at the Hollywood Pantages Theatre in December, projection design has unlocked new storytelling possibilities for theatermakers. It’s been particularly helpful in enticing viewers who are younger, or are more regularly accustomed to consuming movies and TV shows.

“We all watch these expensive, amazing movies with huge special effects budgets, so everyone now has these high visual expectations,” said “Anastasia” projection designer Aaron Rhyne. “I love studying the jump cuts and tracking shots and colors of film and how it all makes you feel, and I get to replicate the style of that in the theater. It’s an opportunity to connect with the modern audience, while still having these performers onstage and in the room with you.”

For example, scenes set on moving vehicles usually evoke the idea of movement via actors’ bodies bobbing and swaying, leaving the audience to fill in the blanks. Yes, it seems like this plane is experiencing turbulence; can’t you tell that the car is speeding and swerving through streets?

But the musical adaptation of “Anastasia” leaves nothing to the imagination. One standout sequence sees the titular Romanov relative traveling from Russia to Paris by train. She and a dozen passengers sing and dance on a rotating metal railcar; behind them, a stage-spanning LED wall displays landscapes that move in tandem with the train.

(Courtesy of “Anastasia”)

It’s as if the audience are following the characters on their intercontinental journey via drone or helicopter. Sure, the actors have some choreographed physicality, but it’s the 3D video background behind them that really sells it.

This kinetic, knockout number is a particularly notable achievement because it unfolds as the story moves locations — a part of onstage storytelling that can be considered laborious. Though transition mechanisms have evolved over the years — from the rope-and-pulley contraptions and counterweight rigging systems to stage lifts and turntables — projection design allows for relatively effortless scenic switches, free of blackouts or downtime.

“You don’t want to have to stop the show because some giant piece of scenery is trucking onstage,” said “Anastasia” scenic designer Alexander Dodge. “This thing has to flow; it has to move at a clip. Even a second too long here and there can slow the thing down and really sink any suspension of disbelief the audience might have.”

With projection design, playwrights needn’t limit their works geographically; a single song can span multiple locations such as the live montages of the Temptations musical “Ain’t Too Proud.” And for Rhyne, these transitions in “Anastasia” are opportunities for digital artistry.

“Of course, many scenic designers have done beautiful transitions with physical scenery, but now, we’re able to bleed through walls and fly over buildings, and do it all timed to music so it all feels exciting,” he said.

“The transitions in ‘Anastasia’ are actually my favorite part of the show. We’re in a dark Russian train station, and then, we slowly move along through the trees of the Polish countryside and arrive at this cherry blossom bridge in Paris. It happens in seconds, and we’re just sliding some content around on the screen, but it’s a signature part of our show.”

“Frozen” and “Anastasia” are two of the digitally forward Broadway productions that rely on projections to build their worlds onstage. Like any other show that goes on tour, they had to somewhat be retooled for the road — a process that can be easier with projections than with traditionally made sets.

“Getting the show up at a Broadway level is like a prototype, a one-off. It’s like Ikea furniture: It’s made to be put together once,” said seasoned adaptive scenic designer Edward Pierce. “Generally speaking, it was never designed, constructed or engineered to come apart and move and be put together multiple times, in theaters of all different sizes.”

Tours try as much as possible to deliver the signature visuals of a production — the smashing chandelier of “The Phantom of the Opera,” the ornate Cave of Wonders of “Aladdin,” or the massive helicopter of “Miss Saigon,” for example. How many trucks are needed to transport the entire show? How long will it take to load in and out of a theater? How much downtime is required between the last performance in one city and the first performance in another?

The smaller these numbers, the better for the bottom line. That can mean scaling back the intricacy of the scenic design or leaving out some scenery pieces entirely (even though, ironically, these tours entertain audiences that are usually double or triple the number of seats of its Broadway venues).

Glinda’s (Ginna Claire Mason, left) floating metal bubble and Elphaba’s (Rachel Tucker) mid-air moment are signature visuals of “Wicked.”

(Joan Marcus)

Many Broadway tours aim to move out of a venue immediately after a Sunday matinee, travel to their next theater Monday, unload into a new space Tuesday morning and, after a sound check and a technical rehearsal, perform Tuesday night. Said Jeff Loeb, general manager of the Pantages, “It’s an incredibly well-planned and a precise operation. Touring companies have [it] down to a science.”

These logistical concerns should not be considered constraints but possibilities for evolution, according to Pierce. For example, after “Wicked” became a runaway hit on Broadway, he and the rest of the creative team were tasked with designing the musical’s West End production and first U.S. tour simultaneously.

“It made us question every choice we made initially, to attack it in a smarter way, with better technology, in a way that makes it repeatable. Maybe we didn’t have enough money in the budget to make it a certain way initially, but because of the success of the show, we might be able to realize it now. And every time we put out another tour, we’re asking ourselves how we can make it better.”

“Wicked,” which uses physical sets, launched its national tour in 2005 on fourteen 53-foot trucks, plus three more with duplicate production elements, rigging and scenery that leapfrogged to the next stop for early setup.

Though projection design isn’t necessarily ever a cost-saver — that footage still requires money, after all — the portability of its hardware does matter.

“The big metric of Broadway touring is trucks — it’s like an old shorthand for the quality, cost and scale of the show you’re making,” said projection designer Peter Nigrini. “But what’s interesting is that all falls apart with projections. It’s fewer physical objects and it’s far from free, but we can deliver a very big, complicated, rich show that lives on much less truck space.”

Major technological advancements have made it possible for productions with prominent projection design to go on the road. Projectors are now made with durable lasers instead of lamps and can pull off more intricate designs than ever. Software programs let designers to create a three-dimensional model of any presenting theater and map exactly where their projections will land onstage. And if a tile of an LED wall malfunctions in the middle of a performance, it can be replaced within minutes.

Without the usual storage and setup headaches, these tours can make more stops in smaller markets that don’t require a three-week stay to justify the cost of driving there in the first place. “Anastasia,” a six-truck Broadway tour, is stopping in five cities in two states in under two months. It has scheduled six-day stints in San Diego, Tucson and Tempe, Ariz., between runs at the Pantages (Oct. 8-27) and Costa Mesa’s Segerstrom Center for the Arts (Nov. 5-17).

But projections do more than ease logistics for touring crews and free playwrights of location restraints. Most notably, the designs help to deliver Broadway to audiences far beyond New York.

Thanks to digitally forward scenic design, the national tour of “Anastasia” (top, starring Lila Coogan) looks almost exactly like the original Broadway production (starring Christy Altomare).

(Evan Zimmerman, Matthew Murphy)

“It’s very important to me that someone from Boise to Cedar Rapids to Buffalo gets the same experience as someone on Broadway,” Ross said. Geography no longer matters.

“Yes, some of the set has to be adapted for touring concession, but with video and projections, the cumulative effect of it still feels like the same show. I’m very excited that we can keep the standards of ‘Frozen’ as high as it is on Broadway as it moves through the U.S. and the world. That’s the whole point of touring this thing anyway, to bring it to people.”

Dodge agreed. Audiences today are exposed to so much more. “You can’t be like, ‘These people from this backwater town, they don’t know what’s good,’ ” he said. “Yeah, they do. They have so many ways to get entertainment at this point that they’re as sophisticated and savvy as anybody else, so they can’t be expected to buy a full-priced ticket and get sort of a half-assed show. The quality has to be really high for everyone.”

In fact, projection design allows the standards of shows in transit to be kept so high that sometimes they’re brought back home to Broadway. Such was the case with “Dear Evan Hansen,” an LCD-heavy production with a tech-centric plot.

“Dear Evan Hansen” returned to Broadway with a technological upgrade.

(Matthew Murphy)

The tour’s LCD screens had a noticeably higher resolution than the Broadway version, which had been running for nearly two years with the same screens. “It’s like when you look at your 2-year-old iPhone and think about when you got it, it seemed like the slickest thing in the world,” said Nigrini, who designed the show’s projections. “We’re trying to reach teens who are skeptical about theater, so the actual technology needs to feel contemporary. As soon as it starts to feel like an old cellphone, it’s a problem.”

The musical’s producer Stacey Mindich noticed Nigrini’s elevated displays on the national tour, which kicked off in Denver last fall. “Once I walked into that theater and saw how gorgeous the projections looked, I turned to Peter and said, ‘Please get me that on Broadway right now,’ ” she said. The upgrade at the Music Box Theater on Broadway took place during a performance break this last spring. “We have a commitment to keep this show updated and looking perfect for, hopefully, years to come.”

Though projection design has been around for decades, it’s thanks to the groundbreaking work of Wendall K. Harrington in “The Who’s Tommy” in 1993 that the field has expanded to what it is today.

“The scale of it was completely absurd, and the amount of handcraft involved was akin to weaving tapestries,” recalled Harrington of the show’s 54 slide projectors that pointed upstage. “While the goal was to appear effortless, I think the audience was wowed by the complexity of what we were doing without totally understanding what it was.”

Over the years, the quality of the hardware has vastly improved to allow for much more nuance, while the costs have lowered. The behind-the-scenes headbutting with scenic designers and lighting designers has eased tremendously. Like every other design field, the specialty is being taught in drama schools.

Wendall K. Harrington collected critical praise for her groundbreaking projection design in 1993’s “The Who’s Tommy.”

(Peter Cunningham)

“Projection is a tool of visual storytelling, like sets and lights and costume,” said Harrington, who established a graduate theater training program on the subject at Yale School of Drama. “Yes, the technology keeps changing, and we have a rotating series of workshops, so the students are exposed to as much as possible. But it’s not about what it takes to do something, I can always find someone to do that. It is the ideas I find that are in short supply. It is most important to find the unique way to tell this story, to find what you want to say.”

This distinction is key: Projection designers are also artists who help tell the entire story, not merely technicians providing a service. They are full members of a production’s creative team, they have their own union. They are specialists of a standalone design field.

“This has been around long enough, there’s no reason to ignore it anymore,” lamented “Rock of Ages” projection designer Zachary Borovay, who successfully spearheaded a campaign for a category at the Drama Desk Awards in 2008. Still, projection design is not a category at the Tony Awards. Borovay says that might be because critics, Tony voters and audiences at large don’t always understand what they’re seeing.

“Last season, some nominations were with scenic design, some were with lighting — how does one determine that, and why?” he asked. “Are you lumping it in with other stuff based on function, or can you qualify based on emotional impact, an intangible thing? Is that shot projected on Lee Harvey Oswald’s T-shirt in ‘Assassins’ — one moment, one frame — considered projection design, lighting or just a special effect?

“I truly believe we don’t do this for awards, but it’s frustrating when your work is omitted because it’s hard to tell what your work is sometimes,” Borovay added. “We don’t always ask ourselves these questions either; we just try to do whatever we can to make a show better.”

Regional theaters aren’t waiting for any further stamp of legitimacy. More and more of them are embracing projection design, not only to serve their local audiences but also to support their theatermakers.

“It’s part of the decision factor, just like possibly programming a show with an orchestra or a large cast is,” said Danny Feldman, producing artistic director of the Pasadena Playhouse. “To make the impact we want and to honor what the playwright is saying, what is it gonna take? Do we do a weakened version, or do we find more money to do it right, or do we not do it at all?”

The Playhouse rents all of its projection systems for each production that requires it, including its upcoming staging of Lauren Yee’s internationally set play “The Great Leap.” Hana Sooyeon Kim is not only designing the projections but is also tasked with negotiating prices with equipment vendors to achieve her visions onstage. “The toughest part is trying to meet the budget as well as getting the best equipment possible,” she said. “I don’t necessarily dread this part; it’s a vital part of the process to take control of the final look of your work.”

Center Theatre Group presents touring shows and produces new pieces throughout its season and, therefore, works “to make sure the technology is on par with the tours we bring in, because we know our audiences are going to expect that,” said producing director Douglas Baker. For its digitally forward shows, the venue has invested in the purchase of multiple projectors and rents additional equipment to supplement or to try out newer technology.

“We try to balance the season,” said Baker. “I do feel sometimes the older audiences long for the hard scenery, with the sets flying in and out, and I think we’ve all seen productions where what’s happening in the story doesn’t match with the look of the production. But I can’t imagine making a decision about a show because, well, we need a less digitally forward show. It’s just, what are we proud to present?”

Qui Nguyen’s projection-integrated play “Vietgone” debuted in 2015 at South Coast Repertory.

(Debora Robinson / South Coast Repertory)

Whatever the cost, the choice for a regional theater to prioritize projection design can pay off in the long run. “It keeps us flexible so that, if someone comes in with a new play and wants to push the technology to its boundaries, we want to make sure we can say yes as much as possible,” said Matthew E. Chandler, production manager of South Coast Repertory in Costa Mesa, which also owns multiple projectors and rents when necessary. It allowed the company to debuted Qui Nguyen’s “Vietgone” in 2015, with projection design by Jared Mezzocchi. It then moved off-Broadway and has been produced 21 times since 2017, according to its theatrical licensing company, Samuel French.

“We may not have the Broadway funds, but we want to develop things that can go off and have a second life,” Chandler said. “We’re like an incubator. We want to make sure we’re supporting the art form in the best way possible and giving our artists the best chance possible to succeed. Keeping up with this technology is part of that.”