[-KarumA-]

Originally Posted by 5yewy5r

I couldn't tell if the avatars were actors heavily modified with CG and make up, or if they were entirely CG. Can anyone clarify?

The facial features are based on actors, by that meaning facial features. I found a site to explain it all, it's quite interesting cause they used a new system for the muscles etc. in the models

http://www.techradar.com/news/video/...-avatar-658031

Lemmon adds, "We used a lot of photographs and scans of the actors and tried to incorporate the details of the physical actors into the digital characters – for both the Na'vi and humans. There are some characters like Jake, who's played by Sam Worthington, where there's both an Avatar double and a digital double.

"There's a lot of data that we captured through digital scanning and Lightstage capture. In addition, we did a lot of extra texture and shader work to make sure all that detail went into the final renders."

A new muscle system

For animating the digital characters in Avatar, Weta Digital had to develop some key technologies that would simulate realism as accurately as possible. Previously, Weta used relatively simplified muscle-simulation systems to generalise how muscles deformed a character's skin.

With Avatar, CG supervisor Simon Clutterbuck led the team to create a more accurate skeletal and muscle-simulation system. "It's quite cool now. Muscles intercollide, preserve their volume and are anatomically correct," says Lemmon.

"There are tissue layers, tendon sheets and all the critical parts of how a muscle system works. It gives a much more realistic starting point for creating believable creature deformations such as all the sliding under the skin and the dynamics of flesh as it moves."
For the Na'vi to be believable, realistic facial animation was crucial. The Na'vi experience a wide range of emotions and the facial animation had to convey these in a realistic way, or potentially fall into the 'Uncanny Valley.'

Weta used a variety of techniques to get the facial animation to a realistic state. First of all was facial motion capture. Using a high-definition video camera attached to the face of an actor and markers on the face, Weta's in-house software was able to map out which muscles in the face were firing.

The underlying technology is based on Paul Eckman and Wallace Friesen's Facial Action Coding System (FACS). By creating a map of muscle firings, Weta was able to retarget the motion data onto faces that don't match directly – in this instance, the Na'vi.

"We started doing this when we were working on King Kong," says Lemmon. "Andy Serkis was playing Kong and his facial anatomy is fairly different from a gorilla's. By capturing the muscle firings, we were able to retarget the motions back onto an animal with different anatomy and topology. We were looking to do essentially the same thing with the Na'vi but in a more sophisticated way."

"This system allowed us to generate a lot of detail in the motion of the faces," Jones adds. "Jim shot a ton of HD reference of his actors and that ended up being the saving grace for the animation process. Once the facial solve came out of motion capture, we would submit side-by-side renders of the real actor and his avatar/Na'vi counterpart, and tweak and adjust the facial animation to get every last nuance into the performance."

Advanced facial rigs

In order to create and retain the detail in the faces, Weta upped the ante in facial rig complexity and mesh resolution. "The facial rigs are by far the most advanced I have ever worked with," proclaims Jones.