BACK TO NARNIA

The Senate VFX completed 250 exciting shots for 'Dawn Treader', 215 of which appear in the finished film, covering full-scale CG environments to embellishments to bring some of the magic to Narnia.

Spitfire
The Senate VFX started creating previs for the opening shot in mid-2009 for VFX Supervisor Angus Bickerton to discuss with Director Michael Apted. The shot begins at a stained glass window high in a tower, pulling back and moving right down to street level – all created in 3D at The Senate VFX. As the camera pans the sky, a Spitfire flashes across the screen and they pull back across the road. The full shot was created in previs, for which they modelled the Cambridge King's College building and built a camera move. They took this move onset for the crew to try to reproduce using a Technocrane.

"The crew wasn't able to achieve the first part of the shot, but we did manage to create moves that simulated the way a crane moves in terms of tilt, pitch and height, and stitched the live action camera onto their 3D camera," explained VFX Supervisor Richard Higham. Consequently, the first part of the shot is the invented camera, and the second part is live action, still displaying our 3D buildings in the background. The only real objects in the scene are the people crossing the road, the road itself and the railings. The buildings are all CG – the gatehouse and walls, King's College chapel and other college buildings – requiring extensive detail and time."

Turning Blue
Ideally, Richard always prefers to work with HDR data for lighting but in this situation, the production used about 140ft of blue screen, which effectively turned all on-set lighting blue. So they had to apply some creative lighting to produce the correct time of day.
Richard said, "Cambridge, of course, was extensively photographed at high resolution to use for modelling, colour and to extract textures. But the college is a very large building and they had no access to the upper portions, requiring long lens zooms and manually calculating the correct dimensions, as well as adding in realistic detail, breaks, chips and weathering. We were also building our work to come very close to camera, so all CG had to be high-res from start to finish. A quick projection wouldn't work."

They were able to follow the previs'd camera move right down to where the real camera began, shooting people on the street. The idea was to let the audience wonder for a few moments whether they were already in Narnia, revealing only the colourful stained glass window, stone structures, spires and ramparts. But the Spitfire was their first clue of England, also created by The Senate VFX team.

Unfortunately, no architectural layouts or drawings for Cambridge University were available, which is why they needed so much photography. Michael Apted had spent some years in Cambridge and wanted a very accurate result. They had to calculate positions from multiple photos and correct distortion in others shot with different lenses, using tools in Photoshop and their compositing software.

Bell Tower
Early in the story at Narrowhaven, the main city on the Lone Islands, the heroes enter a dark, cavernous bell tower. From high above in the ceiling, a crew of dangerous characters suddenly descends on ropes and attacks them. "Nearly the entire environment was built in CG, apart from the floor and several statues seen in the background," said Richard. "The upper reaches of the tower and bells concealing the attackers had to be created. The production wanted to see basilica style architecture over and around them, but the plate only provided a black space, showing no scope. Texturing, detail and appropriately styled arches and pillars behind the statues were required, combined with a great sense of height."

The artists based their model on another they had built for 'The Da Vinci Code' for the Council of Nicaea shot. The team handed over the model to the Art Department to experiment with and modify, and when it came back, they touched it up and textured it, and added shaders.
"Then we could start on the lighting. Again, we started with HDRI but had to creatively interpret lighting for the newly built portions. Angus got involved and wanted more light through the background. Atmospheric beams of light need volumetric lighting that, as far as possible, has to match light sources from the live action. Set lighting creates its own volumetric atmosphere. The team tries to blend any new lights but every scene needs to be handled shot by shot, based on the director's request and artistic decision.

"In this environment, I think the decision to use a full 3D environment was smarter than adding 2D elements because we could give it more scope and a sense of depth, including light. Of course, without blue screen, everyone had to be individually rotoscoped out throughout the sequence and the new background placed behind them."