'Bridge to Terabithia': From Imagination to 3D Enchantment

If you have the QuickTime plug-in, you can watch how Weta Digital created the incredible kingdom and creatures of Bridge to Terabithia by simply clicking the image.

How do you define what imagination looks like? Its the definition of subjective, yet that was the core conundrum in bringing Katherine Patersons Newbery Medal award-winning childrens book, The Bridge to Terabithia, to the big screen. Obviously it was such a vexing concern that it took 36 years, from when the book was published to the film hitting theaters on Feb. 16, for Hollywood to figure it out. A cherished story for a generation of children growing up in the 70s and 80s, Terabithia finally got greenlit last year by Disney and they handed the directorial duties to famed 2D animation director/producer Gabor Csupo (Rugrats, The Wild Thornberrys). With his inventive visual style and adept talent for storytelling that appeals to children, Terabithia became the perfect vehicle to transition Csupo from the 2D world to the 3D world. The film tells the story of Jess and Leslie, two kids that discover through the power of imagination they create the magical kingdom of Terabithia, where magical creatures and adventures beyond their wildest dreams await them when the real world becomes too hard.

Shot in New Zealand, Disney knocked on the door of the local visual effects experts at Weta Digital to take on the creation of the kingdom of Terabithia and its incredible creatures. Matt Aitken, visual effects supervisor at Weta Digital, says their relationship with Disney was just developing when the film was being bid out. We pretty much started this at the same time that we worked on Disneys new logo that plays before their movies. It was first seen with Pirates of the Caribbean: Dead Mans Chest, where we drift down over this landscape and end up on the Disney castle. So this is really the first feature film that we have done with them and Walden Media.

Known for their amazingly complex visual effects work on such Oscar-winning films as The Lord of the Rings trilogy and King Kong, Terabithia was a perfect fit for Weta, allowing them to utilize their technological prowess while also integrating their expertise as digital characterization. There was a huge slate of different creatures that we had to build, creatures and the citizens of Terabithia, Aitken explains. That was work that we felt ready and willing to lead them to based on the experiences that we had on Rings and King Kong. Also, creating the environments of Terabithia was work that we had developed technologies for before.

The film shot in New Zealand in February and March of 2006 and Aitken says Weta was there from pre-production right through final delivery. We were on set for all the scenes that involved visual effects. The two big vfx scenes were pre-visualized. The production organized previs for the big fight in the middle of the film. They used another company for that but we were involved in developing ideas about the content of that scene. We pre-visualized the end sequence ourselves to find the balance between what should be shot on location for the view across the creek into Terabithia. We were working out where the camera should be so its looking at the castle when there is no castle in what they were shooting. It proved to be very worthwhile. Meanwhile, we were already building the creatures while they were shooting.

The creatures culled from the imaginations of the lead characters became the playground of the Weta team. Giants, dragonflies, ogres called Squogres and more needed to take shape from what had previously only existed on the page into living, breathing characters. About the development stage, Aitken explains, The really exciting thing about this show was this great production art that we got from Gabor that he had worked up with his designer friend, Dima Malenitchev. They are very simple, almost sort of pencil sketch illustrations, but they are very evocative of character. The process of taking these sketches and realizing them as fully rendered, 3D-believable, natural-looking creatures was really the challenge for us. The process of interpretation was split into two components. First, the process of taking the pencil sketch and creating a natural looking creature was greatly assisted with the involvement of our in-house visual effects art director, Michael Pangrazio, who worked out these collages in Photoshop. They were true to Dimas illustrations, but also had a much more natural look to them, like you had taken a photograph of the creature. We used those as a basis for building the creatures. For the crew here at Weta, it became very clear to me that what people were really enjoying about working on this show was the design element, which was different from work we had done in the past. Our people just reacted really positively and strongly to the creatures. Secondly, it was about finding an animation style or a motion style for these creatures so they move in a way that is true to the intent of the illustrations, but is natural as well. We did different motion cycles, different run cycles. We based the Squogres run cycle on a dog running, but we had looked at squirrels running and cats running in different ways.

Once the design was locked, Aitken says it really came down to creating performances with the creatures under Gabors direction. We have an understanding that there are certain things we need to do on a technological level, but also with the way that we animate the creatures and create a performance with them. We do have experience in that area that we can bring to bear. If you look at creatures like the Squogres in Terabithia, they have a lot of fur and it has to move naturally and when the creatures jump around, it has to have that dynamic flow. It was all technology we had developed for King Kong, so we had that as a great place to start from. But still we had to go through the process of working with Gabor and finding the character of these creatures and exploring that. Theres no formula for that and its a process of exploration and we have some very talented artists here that are very good at that.

Having made their name with character-driven performance capture technology in previous films, Aitken says they discussed using a lot of motion capture, but ultimately realized that wasnt the way to go. By and large, most of the creature animation in the show were things like the Squogres, which are little squirrel-dog creatures, and the hairy vultures, which fly. With both, it didnt make sense to use performance capture technology to animate those guys. They are much more suited to a keyframe animation approach. But the character of the Giant was inspired by the school bully, Janice Avery (Lauren Clinton). We used a little bit of motion capture for her in a couple of shots. At the end, when she walks out of Terabithia and puts the crown on Jess' head, we did use motion capture there for a couple of shots because it made sense. We wanted her to be completely natural and she is of human form so it lends itself to that, but the majority is keyframe animation.

Despite it being Cuspos first live-action film, Aitken says he and Weta have nothing but praise for his debut. It was fantastic working with Gabor! He has this great tradition in animation so he would bring ideas like the choreography of the fight scene. The kids are knocking around with some Squogres in the fight and he had some great ideas for gags, like the Squogres getting caught in a tree. He seems to have a vast source of these ideas that he can tap into and, also, he had a huge enthusiasm for the process. It takes a long time to develop the pre-production aspect of the creatures and we went over and over each shot as we refined them and he had a huge amount of energy. He was there with us whenever we needed him, either in person or through video conference calls from the States. For the crew, thats always great to have that kind of energy going on.

Talking about the details of Wetas workflow pipeline, Aitken explains, Post-production lasted six months. We delivered most of the work in September 06. They were very happy with the work we did and they asked for a few more shots to fill out the fight scene and the scene at the end of the film, so early November 2006 is when we wrapped.

More than 100 people at Weta worked on the movie at one time or another. There was a core team of about 40 people that worked on it through the whole post process. As always, the timeline was tight, but Aitken says Wetas R&D on other films helped usher Terabithias pipeline along more efficiently. The creature pipeline is well established now. We did some tree work at the end and those are all pretty much entirely digital. We had to replace the trees in the location with a digital forest so we could have the trees part and reveal the digital environment. We had developed proprietary software for the Skull Island scenes in Kong where we could create digital trees with a large amount of detail, so we used that for Terabithia. But our 3D-based pipeline is very much based on Maya, with a lot of proprietary code to tie it all together. We used Shake predominantly as the compositing software and Photoshop for the comp art. The end shot count was 131 effects shots.

Stumped when asked about his favorite sequence of the film, Aitken pauses and chuckles, Thats going to be tough. I wouldnt want to single any one shot really. Im very proud of the Squogres fight. Im proud of the Giant at the door of the stronghold. If anything, that is a shot where you feel the reputation of Weta is somewhat on the line. Its what people associate with us - the creation of characters that arent real but have a subtlety in performance. Also, I liked creating the wide views of Terabithia with the crowds of thousands of citizens. We wanted Terabitha to look beautiful and wonderful. So Im very proud of all the work that the team did on the show.

Tara DiLullo Bennett is an East coast-based writer whose articles have appeared in publications such as SCI FI Magazine, SFX and Lost Magazine. She is the author of the books 300: The Art of the Film and 24: The Official Companion Guide: Seasons 1 & 2.