Documentary filmmaker Bing Liu’s own coming-of-age story unfolded against the backdrop of Rockford’s skateboarding scene.

ROCKFORD, Ill. — Documentary filmmaker Bing Liu’s own coming-of-age story unfolded against the backdrop of Rockford’s skateboarding scene.

That’s where he’d go to escape a rough home life.

“Skateboarding is an ad hoc family; it’s a proxy family,” said Bing, who attended East High School before graduating from Guilford in 2007. “Often, it’s because of the lack of support and structure from fathers or parents.

“This is all learned in hindsight.”

In addition to skateboarding, Liu also enjoys movies, especially so-gritty-and-honest-you’d-swear-they-were-real dramas from the 1990s such as “Gummo,” “Slacker” and the controversial “Kids.” His own personal documentary style was inspired by Spike Jonze who, before directing quirky indie gems such as “Being John Malkovich” and “Her,” made short films about skateboarding.

Just as Liu has been doing since he was a teenager.

“Spike Jonze really influenced me to push the boundaries of skate videos and what they mean,” Liu said. “My skateboarding videos became more and more experimental.”

Liu, 29, now living in Chicago, has combined his two passions into a project that is about to go before movie buffs and Hollywood studio heads seeking the next major voice in cinema.

His documentary “Minding the Gap,” filmed in Rockford over the past several years, will have its world premiere Jan. 21 at the Sundance Film Festival in Park City, Utah, the largest independent film festival in the country. Liu directed, co-produced and edited the 96-minute film.

The real-life tale follows Rockford skateboarders Zack Mulligan and Keire Johnson — plus Liu, who is featured in his own documentary — as they grow and deal with various aspects of fatherhood while finding a respite from volatile families through skateboarding, a pastime often looked down on by mainstream society. Liu has been working on “Minding the Gap” since 2014.

“I haven’t had much time to process [it], actually,” Liu said. “If we would’ve ended up premiering at a festival later in the 2018 calendar, I would’ve kept working on the film up until then. But getting into Sundance meant I, all of a sudden, had to lock the picture as soon as possible so I could schedule and send off to my composer, the colorist, and the sound mixer so they could start their work in earnest.”

“Minding the Gap” will debut in the iconic 318-seat Egyptian Theatre in downtown Park City. It will screen four other times throughout the festival at venues in Park City and Salt Lake City. Awards for top dramas and documentaries competing in the festival will be announced Jan. 28.

As director, Liu is required to attend each screening. Mulligan and Johnson will attend opening night, which Liu described as a gathering place for studio executives from Hollywood to view the film and weigh its merits for a theatrical distribution deal. Each screening is followed by Q&As moderated by Sundance officials.

The film is also listed as one of IndieWire’s most anticipated movies to premiere at Sundance this year.

Though it’s unclear when and how Rockford moviegoers will be able to see “Minding the Gap,” the doc has already gained traction among distributors. London-based theatrical distributor Dogwoof earlier this week picked up the film for international markets, according to a report in Variety.

Liu was born in China and moved to Rockford when he was 8 years old. After he graduated from Rock Valley College in 2008, Liu enrolled at the University of Illinois at Chicago, graduating in 2011. He spent six years after college working in camera departments on Chicago-based commercials, television shows such as “Chicago PD,” “Chicago Fire” and “Chicago Med” and special-effects extravaganzas “Divergent” and “Jupiter Ascending.”

His experience working in fiction helped strengthen his skills as a filmmaker who documents real life.

“I was able to take this experience storytelling in fiction and reimagine it through a documentary,” Liu said.

In the early stages of production for “Minding the Gap,” Liu toured the country visiting skate parks. One day, he was hanging out in St. Louis, skating and shooting the breeze with others.

It was Father’s Day. Liu wanted to know why they were there instead of at home with their dads or children. They discussed their shaky or nonexistent relationships with their fathers.

“That was a light-bulb moment for me in terms of thematics,” Liu said.

As Liu continued making the documentary, his focus narrowed on fellow Rockfordians Mulligan and Johnson. Virtually all of the final product is taken from footage Liu shot in the Rock River Valley.

“They were swept up into this grander idea of fatherhood and skateboarders before I ever knew there was going to be this documentary over the course of [several] years,” Liu said. “Eventually, it became logistically easier to follow them.”

The film is produced by Kartemquin Films, a nonprofit documentary production company based in Chicago. Independent Television Services and American Documentary’s POV are co-producers. Financing was provided by the Corporation for Public Broadcasting and the Sundance Institute Documentary Film Program. Liu brought the project to Kartemquin in 2014.

Liu worked on cinematography for Kartemquin’s “All the Queen’s Horses,” the documentary about former Dixon comptroller Rita Crundwell, who embezzled millions from city taxpayers. It premiered to sold-out crowds in October.

Gordon Quinn, artistic director and founding member of Kartemquin and one of the executive producers of “Minding the Gap,” said Liu’s work reflects the studio’s passion for bringing to the screen character studies filmed over a long period of time.

“Our mission is to play a role in helping develop the next generation of documentary filmmakers and showing how those films can have real consequences in the world,” Quinn said. “[‘Minding the Gap’] talks about a wide variety of coming-of-age issues and issues being born in a place like Rockford.”

Steve James is also serving as one of the executive producers. The director is best known for the 1994 documentary “Hoop Dreams” and the Roger Ebert documentary “Life Itself.” Both were produced by Kartemquin Films and premiered at Sundance before securing theatrical distribution deals.

Liu is a segment producer on James’ upcoming documentary series, “America to Me,” which also debuts at this year’s Sundance Film Festival. Kartemquin recommended Liu to James to help with “America to Me.” Liu showed him footage from “Minding the Gap,” and James agreed to join the project as executive producer.

“He’s got a really unique and terrifically intimate story,” James said. “On top of that, he has a terrific eye and [shot] incredible footage of skateboarding. All that combines to make a terrific and unique film and one that Sundance audiences will respond to.

“Audiences will be discovering a talented young filmmaker who will be making films for years to come,” James added.

The Sundance Institute was founded in 1981 by Academy Award winner Robert Redford. The festival has historically been a tipping point for many blockbusters and awards contenders seeking distribution deals that allowed them to reach a wider audience. “The Blair Witch Project,” “Little Miss Sunshine,” Quentin Tarantino’s “Reservoir Dogs” and this year’s Golden Globe nominee for best drama “Call Me By Your Name” are some of the movies first discovered at the festival.

“Minding the Gap” has received high praise from Sundance officials.

“What emerges is an insider’s story that defies the media’s fixation of►the skateboarder as mindless slacker and digs into the heart of modern-day masculinity,” the festival program reads. “This provocative film explores the gap between fathers and sons, between discipline and domestic abuse, and ultimately that precarious chasm between childhood and becoming an adult.”

Liu said he wants his film eventually to reach its intended audience: lost and confused adolescents.

“Hopefully it speaks to young people,” Liu said. “I feel like they aren’t given a lot of opportunities for them to be spoken to in film. Hopefully they’ll feel less alone.”

Early versions of “Minding the Gap” have been screened in front of test audiences and Kartemquin officials — to mostly positive reactions.

“Sometimes their feedback can put you through the wringer, so you have to be prepared for that,” Liu said. “But for the most part, it’s consistently been about how charismatic and magnetic the characters are. A couple of people have said in the screenings, ‘Wait, that was a documentary?’”

Adam Poulisse is a reporter for the Rockford (Ill.) Register Star.