[DigitalToday reporter Chi-gyu Hwang] Director Kim Sung-soo (김성수) of the 13 million-viewer film "12.12: The Day" is continuing bold experiments with AI.

At ACFM 2026 held recently at Busan Exhibition and Convention Center (BEXCO), he presented the AI short film "Worm Train." He also plans to actively use AI in key action scenes of a planned seven-part series. Ultimately, he aims to take on AI scene production for films. That makes it fair to call him an early adopter of AI in film.

Although an early adopter, Kim is also a thorough realist in how he approaches AI. He is far from what he calls "AI supremacism" that assumes "AI can do everything." AI clearly has limits. Even as AI improves, he also sticks to the principle that a film’s edge still depends on creators obsessing over details down to the smallest things.

Kim, while maintaining realism, is clear that AI is a game-changing technology in film that cannot be ignored and should not be ignored. Even if a film cannot be made entirely with AI, he says the disruptive power of AI as an innovative technology must be acknowledged. He believes the day is not far off when the "AI" label will drop from films now called AI films.

At the ACFM 2026 venue, the reporter met Kim and spoke about changes AI could bring to the film industry, the role of a director, and the competitiveness of video content in the AI era.

Kim’s interest in using AI in film production grew in earnest while making the blockbuster hit "12.12: The Day." He began experimenting with AI video, thinking it could help recreate late-1970s scenery and also help create realistic wide shots. Being able to quickly see results of what he had in mind was also an experience made possible by AI.

At this point, "Kim Sung-soo’s AI theory" can be summed up as people using AI, not AI replacing people.

Kim said he initially saw AI as a destroyer or replacement for films, but his thinking changed as he made work himself. His question for AI also shifted from "How cheaply and easily can it be made?" to "How does the way films are made change?"

Based on his experience making "Worm Train," Kim’s answer is that no matter how good AI gets, a feature film cannot be made alone. That is why he applied much of the existing production workflow to AI film as well.

“At first I tried to do it alone, but it wasn’t easy. Even AI films require experts across various fields needed for films to collaborate with a sense of responsibility. The director has to act like an orchestra conductor, bringing these experts together and facilitating communication,” he said.

Kim said dealing with AI-made characters is not drastically different from existing films. “I think of it as casting rather than modeling AI characters. When the film comes out, the audience will see one person, but we went through a process of creating dozens of actors, assigning meaning to them and making them act,” he said.

Kim collaborated with Kling AI during the production of "Worm Train." He used the Kling 3.0 model until March, but a scene where passengers bump into each other could not be implemented with AI. When he tried Kling 4.0 in August, the screen quality rose to the level he wanted. “When I made the subway scene with the Kling 4.0 preview version, the texture and weight at the moment of collision were captured 그대로 in the scene,” he said.

Even if AI can now produce realistic video, directors still have frustrations. He said he is especially disappointed when results do not come out as desired in terms of aesthetic sense or control. “You don’t get a film by stitching together 10 great images. In a film, there is tension and emotion that arise at the moment one shot collides with the next. AI can generate endless footage, but it still cannot create that collision and those gaps,” he said.

Because Kling AI is a general-purpose model for everyone, not AI made only for him, it is difficult to fully satisfy a professional’s thirst for uniqueness. And relieving that thirst ultimately is the role of people, not AI. He said the persistence to avoid easily compromising with AI’s quickly produced, adequately good results, and to implement something even a little closer to what is desired through collaboration among experts, determines whether a film is immersive or not.

Kim stressed, “There is a lot of excellent AI video now, but there are not many films you can watch with immersion and enjoyment. Immersion happens in a few seconds. It takes less than 10 seconds to feel that music sounds good. In that short moment, if you want viewers to immerse themselves in a character or image, you should not leave it to AI. Film professionals need to be involved by field. Only then can you get something plausible and immersive that audiences can truly empathise with.” He added, “Famous creators have no intention of watching the obvious things others make. Creators must use AI in a special way to make the images or stories they want. To do that, they need to run a great many experiments.”

Kim said making an immersive film with AI also requires breaking with a mindset of making things cheaply and quickly with AI. “If you only try to make it cheaply and fast, the result will inevitably be rushed. AI films also need to be made with care and to be done extremely well,” he said, raising his voice.

When it comes to storytelling, he said the human presence in AI film production becomes even bigger. “In storytelling and expressing characters, AI alone has limits. The top players in the film industry need to handle AI and raise the technology level. Only then can AI-made content draw a ‘Not bad’ reaction from audiences with high standards,” he said.

"Worm Train" reflected many collaboration norms from the traditional film industry, but the importance by role has changed somewhat. He said the art director’s role has grown compared with existing films. “The art director sets the design and key concept. Quality improves when someone with an eye makes requests and reviews the results. Many AI artists today have strong artistic sensibilities. But AI artists cannot do everything well, from creating a story to directing actors to shaping the mood of a scene,” he said.

Kim said the director in film has been an orchestrator, but an AI film director is also given the role of a simulator on top of being an orchestrator. “You have your thoughts and imagination, and if the gap between what you imagined and the output is small when you turn it into a film, you simulated well. If you make it and it is not fun, not funny, not sad, has no style and is not immersive, you simulated it wrong,” he said.

After "Worm Train," Kim is also seriously considering making a feature-length AI film. He has not entered production, but he said the warm-up has already begun. “I didn’t plan "Worm Train" from the start as an AI film. It was an item I had wanted to do for a long time, and I decided to produce it because I thought it would be good with AI,” he said. “Among the stories I have already developed, there is one that I think might work with AI. For that, I am revising the screenplay now,” he said.