'12.12: The Day' Director Kim Sung-soo Embraces AI: 'I'll Never Go Back'

Kim Sung-soo, the director of the Korean box office hit "12.12: The Day," once considered AI a destroyer of the film industry. On Sunday, speaking at a session hosted by Kling AI at the Busan International Film Festival's Asian Contents & Film Market, he declared the opposite: the technology has become part of his craft.

"I'll never go back to the way I used to make films," Kim said.

What changed his mind?

The turning point was "Worm Train," an eight-minute short Kim initially abandoned because AI could not render its key scene — a giant insect colliding with a packed train crowd. Months later, the technology had caught up.

"Technology doesn't replace creativity. It shows what's in your imagination," Kim said.

He did not make the short alone. Kim assembled a nine-person team, including an animation art director and a music director. Although the film could have been made entirely with AI, the team generated only part of it and handled the rest with conventional filmmaking methods.

Kim plans a similar hybrid approach for a seven-part drama series now in development. Its nearly 15-minute opening chase on the Gyeongin Expressway — a sequence he said would require "enormous financial resources" to shoot conventionally — will first be generated with AI. The generated footage will then determine which shots need actors on set and where traditional VFX come in.

Does AI replace filmmaking skill?

Kim shared the stage with three industry figures: Harry Hyun, director and CEO of AI production company MooAm; Chinese animation director Li Wei, co-director of "Jiang Ziya"; and Lee Sangwook, producer and team manager at MBC C&I's AI Contents Lab.

Li made the case for animation. Presenting a trailer for "Born of the Tide," a 105-minute AI-animated feature about China's boat-dwelling Tanka community, he said AI works best at the trial-and-error stage: concept designs that once took enormous time to draw by hand can now be visualized quickly and shared with the team.

"AI can generate many things, but the choice and the details all come down to the director," Li said.

Hyun agreed that filmmaking skill makes the difference. "Faces look identical, sets look identical, lighting looks identical," she said of AI output made without it. That is why MooAm looks for AI artists who have directed at least one live-action short.

Otherwise, she said, AI production is not fundamentally different from a conventional shoot — only more efficient. What changes is the crew. Her directing team now includes an "AI coordinator" who decides which cuts will be generated, keeps a continuity script for them and checks with AI artists that everything cuts together. Even assistant directors need a basic grasp of AI, as gray screens marked with tracking points replace green screens.

Lee's lab is building those skills through production. It is making "Rendering Love," a short-form K-pop romantic comedy about a virtual idol group, with "Parasite" producer Barunson E&A developing the story.

"If even one or two individuals lag on the learning curve, overall quality can suffer," Lee said of keeping pace as AI models update.

What comes before technical standards?

Kim argued that rules on commercial use and permissions should be settled before the industry sets any technical standards.

"Whenever I generate outputs, I scrutinize the results closely to ensure they do not infringe upon existing works or violate anyone's publicity rights," he said.

His prediction for the long term: "In the future, we won't call AI movies 'AI movies,' just as we no longer call films 'color movies.'"