The Call of the Wild” editor David Heinz has worked on “The Jungle Book” and “War for the Planet of the Apes,” but this movie starring Harrison Ford and an animated dog named Buck was different.

“If you think about it, the lead of the movie is fully CGI and never speaks,” he said, also calling the film an “ambitious undertaking.”

Before working on “The Call of the Wild,” Heinz didn’t have any kids. Now, he has a two-year-old daughter and just became a second-time dad to a baby boy. He spent a year working on the film alongside co-editor William Hoy and director Chris Sanders. Together they visualized the film in its entirety before anything was ever shot.

“It takes a lot of planning,” he said. “There was just no way to shoot it like a normal film. We couldn’t shoot it with motion capture and Buck isn’t just CG, he’s also animated.”

With the central character not speaking the entire time, it was up to the animators to create the nuances and expressions, but it was up to Heinz to relay the moment-to-moment emotion of what Buck was thinking. That was where Heinz relied on the story-boarding and pre-visualization work as a guide.

“That was the other challenge, cutting the film and making sure the audience understood what the dog was feeling,” he said.

Another helpful aspect was John Powell’s score, which ultimately served as Buck’s voice.

“His score tied the whole thing together. This dog starts as a puppy and becomes this adult,” Heinz explained. “It’s this careful balance of a coming-of-age story and maturing. It starts delicate with this childlike tone and becomes serious as the drama evolves.”

Heinz reread the book before embarking on the project, something he hadn’t done since he first read years ago, to get a feel for the tone.

“It’s quite a dark story and a brutal story of survival,” he said. The story’s dark tone meant many elements of the book could not be captured, especially as they wanted to keep the film a family-friendly one. “That was the biggest challenge trying to stay true to the source material while keeping the structure and the heart of the story so parents could still bring their kids to it.”