While young Simba was working on his roar in the new “Lion King,” his designers and animators were laboring over a good deal more. All the hairs on the cub’s body, the detailed color patterns of his fur and the movement of his little legs through the savanna were the efforts of a Pride Rock-size army of visual effects artists.

The film’s director, Jon Favreau, worked with effects company MPC Film, which also helped bring the animals of the filmmaker’s previous movie, “The Jungle Book” (2016), to photorealistic life. But unlike “The Jungle Book,” there are no humans to draw away the eye. All of “The Lion King” was digitally created, save one shot that the filmmakers refused to divulge. And the focus was on making the animals as familiar-looking as they would be in nature.

For reference, the filmmakers visited Disney’s Animal Kingdom in Orlando, Fla., where the animal-science department let them observe and record some creatures. But it was essential to see the lions in the wild, so the creative team traveled to Kenya to observe and take some photos — actually more than 12 terabytes worth of images. With this visual information, the animators at MPC Film (a division of Technicolor) began sculpting.

Here is a closer look at how little Simba became a lifelike standout on the big screen.

THE FACE

In determining some of the looks and mannerisms for young Simba, the visual effects supervisor, Adam Valdez, focused on a couple of cubs he saw at the Maasai Mara game reserve in Kenya. “They had a certain character about them,” he said in a phone interview, “a certain plucky energy.” After bringing images of these cubs back to the studio, Valdez asked himself, “How is this character going to be appealing without looking too cartoony and how am I going to make it relatable?”

He and his team focused on the particulars of a lion’s face, which is longer than that of other cats. An emphasis was put on the animal’s majestic prow, that noble line from the top of its forehead to the tip of its nose. But it was also important to offer ways for audiences to connect this version of Simba to the one in the 1994 original. They did that by giving him a little bit of roughed-up hair on top and also by making his eyes a little rounder and more open than a lion’s would normally be.

THE FUR

Once one of the most prohibitive challenges of digital animation, fur has come a long way. And yet, it is still incredibly difficult to get right. “These craftspeople spend a lot of time managing the millions of hairs that are on these characters and making sure that it moves with the correct physics,” Valdez said.

Artists build fur by creating what are called “guide hairs,” setting parameters for how thin or how smooth they should be. Then special software uses the information from those guide hairs to duplicate them and make them grow around the animal’s body.

They also lay a digital pattern on the skin. “The pattern might tell the hair that it should be scraggly, or another layer of the pattern could tell every hair that grows from that piece of skin to be more stuck together with its neighbors,” Valdez said.

As for the shades and patterns of Simba’s hair (like the spots on his belly), Valdez said that’s also a result of software that tells each hair what color it should be: white, tan, black. “If you place it all right, you end up with what looks like a lion.”

THE MOVEMENT

Creating a character with appeal is one piece of the puzzle. Getting it to function in a way that feels right is another. Valdez said that he and his team first thought that since a lion cub like Simba was already so cute and warm, it would be easy to create his movement. But it turned out that cute little lions are laborious to light correctly yet still fit well into the environment.

And playful scenes with young Simba and Nala, when they engage in big actions like running and tussling, meant a lot of animation for their tiny legs. “Sometimes they would look a bit awkward,” Valdez said. The animators figured out ways around this by sometimes putting plants in front of the camera to block certain moments of action.

And then there’s the talking. “You have a challenge anytime you have a mouth form that doesn’t mimic a human mouth,” Valdez said. They didn’t want to end up in the uncanny valley when it came to how the characters spoke.

He said there were a couple of choices. Simba and the others could mumble because they don’t have the maws for articulated human speech. But that makes it difficult for audiences to understand them. Or their motions could be simplified, which is what the filmmakers settled on: When the animals speak, there’s enough movement to believe that words are being formed without it looking too distracting.

“It just so happens that lions have little markings around their eyes and mouths where if you go too big, it starts looking really cartoony, and it looks like their faces are made out of rubber,” Valdez said. “It’s a pretty delicate, tricky balance, these things.”