In a year dominated by sequels, Rio (opening today from Fox) follows Rango as one of the few original bright spots. And bright is the operative word for Blue Sky's sixth feature, a musical extravaganza about the last two macaws of their species: Blu (voiced by Jesse Eisenberg), who can't fly, and Jewel (voiced by Anne Hathaway), who refuses to open her heart.

Directed by Rio native Carlos Saldanha, Rio captures the landmarks and rhythm of the beat that define this famous Latin American paradise.

However, Blue Sky certainly had to raise its game to achieve the level of animation necessary to match Saldanha's ambitious vision.

Birds were the first challenge, of course. There are 12 bird species (chicken, crow, egret, frigate, goose, macaw, sparrow, spoonbill, toucan, cockatoo, cardinal and canary) and a total of 51 unique ones. The hero birds required special rigging for the wings, which double for gesturing when not used for flying. In the case of Blu, that's most of the movie. In fact, Blu's entire groom had around 5,000,000 individual hairs to make up all of the feathers.

"The wing rigs are complicated and you want to give them some personality and the ability to emote and articulate their feathers," suggests Robert Cavaleri, CG supervisor. "And those are two very different kinds of control sets that you have to blend together in a way that allows to them to go from being like a normal bird and something that can be caricatured in a particular way."

According to Galen Chu, supervising animator, "Rigging helped us use these wings like fingers to be able to point and grab an object. It took about nine months of back and forth between modeling, rigging and animation to make it work."

Fur and feathers are done procedurally at Blue Sky: the grooming tools are created in Maya, which is the primary software, and then translated into the proprietary renderer, CGI Studio, which contains a special ray tracing technique.

"The feathers tend to overlap and penetrate a lot, so as you're evaluating the character animation, there's a lot more attention to detail and it can be somewhat difficult to control," Cavaleri adds. "We have a lot of tools now to manipulate the feathers, but considering that there are so many of them, it tends to go slower and the birds tend to be heavier than the humans."

Speaking of which, Rio represents the first Blue Sky film populated by humans (Ice Age contained glimpses of cavemen that don't speak). While they're definitely stylized, they certainly had to have pleasing skin, so Blue Sky utilized sub-surface scattering as part of a larger global illumination effort that goes beyond the Connecticut-based studio's signature ray tracing rendering with its proprietary CGI Studio.

Linda (voiced by Lesley Mann), for instance, who reared Blu in Minnesota, required the most attention, including her long, flowing, brown hair. "We had to improve the hair rig called Follow Through for Linda," explains Matt Simmons, animation technical lead. "The R&D guys rigged up the fur that we have so we were able to do more poses for Linda's hair and handle the collisions. If a hair went right through her face, we needed a nice way of getting it out of there so it looked natural."

Chu says her mouth was also tricky, "and the animators tended to push it a little too much on the lip sync or the expressions and it was always the job of the director or mine to pull back to where we needed Linda to be."