Above: Actors Andy Serkis (right) and Toby Kebbel on the set of Dawn of the Planet of the Apes and (below) the resulting film scene. Photo: Weta/20th Century Fox/Reuters

It’s not easy playing an ape, even a highly intelligent one, but if Andy Serkis succeeds in captivating moviegoers, he will be thanking the obscure world of motion capture, a digital technology that accurately translates performance into animation.

For Dawn of the Planet of the Apes, opening in US theatres this weekend, director Matt Reeves says he pushed the boundaries of motion capture to achieve “photo-reality” in rendering the apes, particularly in their facial expressions.

In doing so, Dawn could usher in a new age for actors, allowing them to dream of delivering award-worthy dramatic performances using a technology generally utilised in sci-fi blockbusters.

“One of the hardest things to do is to create characters which are emotionally engaging and truthful,” said Serkis, a British actor who has become a seminal figure for motion capture by bringing to life creatures such as Gollum in Lord of the Rings and King Kong.

Serkis said advancements now mean that a character’s facial expressions and emotions have a ‘one-to-one’ relation to the actor’s.

In the sequel to 2011’s Rise of the Planet of the Apes, Serkis plays Caesar, a brainy ape who leads his species and negotiates their interactions with humans.

In motion – or ‘performance’− capture, multiple cameras record an actor playing scenes in a suit covered in hundreds of dot-like sensors, often against a green screen that visual effects artists then digitally transform into locations. The cameras capture the movements and feed them to computer software, where digital-effects artists animate characters accordingly.

For Dawn, Reeves eschewed the green screen and instead had the actors playing apes don their motion-capture suits on location, interacting with the actors playing humans.

Once filmed, the scenes featuring the apes were sent off to Weta Digital, the New Zealand-based company that created the fantastical world of Middle Earth in Lord of the Rings and The Hobbit films.

The Weta artists digitally layered ape qualities, from their anatomy to fur to movements, on to the faces and bodies of the actors. Lighting was often key to the illusion: each individual strand of fur and the glint in the apes’ eyes responded to the light of the forest.

Joe Letteri, the Oscar-winning visual-effects supervisor at Weta working on Dawn, said making human movements mimic an ape’s took enormous effort, but the emotion came from Serkis.

“If you look at (the film) side by side, there’s no question that’s Andy’s performance,” he said.

Serkis’s many screen credits have earned him respect among the filmmaking community and fans of the franchises, but he has yet to be recognised in the awards race for his motion-capture roles.

He attributes this to a perception by the industry that motion capture is digitally driven and not creditable to the cast. Serkis believes things will change if more people are aware of how the animator’s artistry is married to the actor’s.

It’s the most liberating tool for an actor, because you can never be typecast

“To deliver an emotionally engaging performance, does an actor have to be seen on screen? That’s the big question. It is important that the role of the actor is acknowledged,” he said.

That could dawn on audiences soon.

“For the first time, there is the option of very faithfully replicating the performance of what the actor delivered on set,” said Paul Debevec, chief visual officer at the USC Institute of Creative Technology.

Doubt as to whether such actors should be considered legitimate nominees for awards “should just be gone,” he adds.

Debevec is a member of the Academy of Motion Pictures Arts and Sciences, the organisation that hands out Oscars, and sits on its science and technology council.

He is also the chief scientific consultant for Otoy’s Lightstage, a capture technology that digitally scans actors in 3D and can bank their appearance so they can play younger versions of themselves even as they age.

Lightstage is derived from the technology used to age and to make Brad Pitt younger in 2008’s The Curious Case of Benjamin Button, which earned Pitt an Oscar nomination for best actor, a notable moment for digitally enhanced performances.

Most recently, while Sandra Bullock and George Clooney weren’t transformed in Alfonso Cuaron’s Gravity, they were placed into outer space using Lightstage performance capture. Bullock was nominated for best actress at this year’s Oscars, and Cuaron won best director.

The majority of big-budget films coming up over the next few years, from August’s Teenage Mutant Ninja Turtles to the next instalments of the Avengers, Avatar and Star Wars franchises will be using performance-captured leading characters.

“It’s the most liberating tool for an actor, because you can never be typecast − you can play anything beyond your height, your shape, your sex, your colour,” Serkis said. “Whatever you are is not an obstacle.”