"During production aerial plates were shot for use as backgrounds in some shots, these were shot at Wharariki Beach in a remote part of New Zealand's South Island. We were also provided with blue screen elements of Susie running which were shot in the studio. Wide shots used a digital Susie which we could track into the background plates.

"Creating the digital ships and the bottles containing them involved balancing the scale of the ships with a design that evoked the miniature ships that Susie had enjoyed making with her father. The ships we built were more complex than the miniatures, which would have been too simple visually, but lacked most of the design features of a fully-rigged sailing ship, which would have worked against establishing the connection. For this reason also the ships have giant paper sails rather than flapping cloth sails. We created bottles made from antique glass with all its imperfections to echo the miniatures once again and add realism.

The supervisors "didn't always understand where it was headed and how it would all look when it was completed," but in the end it fit together seamlessly and daringly.

"When the bottles smash apart we had a choice between running the destruction as a physical simulation, or breaking the bottles 'by hand' and animating the flying pieces with keyframe animation. We chose the latter for the main pieces of glass because it offers a high level of control over the shape and detail of the destruction. Peter had very specific notes on how the bottles should break: bottle necks rolling on the beach, jagged pieces hanging off bottles, to add to the sense of violence. Smaller shards of glass which fly out when the bottles shatter and add to the explosive nature of the collisions were animated with dynamic simulations, where the physical properties of the collision are modeled in the computer and a mathematical simulation calculates the path of each shard. This enabled us to add a lot of fine detail to the effect."

In all, there were 663 vfx shots, most of which were actually earthbound and "invisible," such as placing a cornfield behind the suburban street where Susie and her family live, creating a sinkhole in a rural field and adding exteriors to the house interior sets.

"We had to create a sinkhole that grows throughout the course of the film," adds Christian Rivers, visual effects supervisor. "The film starts with the Salmon family dumping their old refrigerator. At the end of the film, Mr. Harvey dumps the safe that contains Susie's body into the larger sinkhole. The sinkhole…is entirely digital."

As Weta progressed throughout the vfx work, the supervisors didn't always understand where it was headed and how it would all look when it was completed, but on the night they finished and delivered the last shot, Tait made a slide show of stills from his favorite scenes. He remembered "the history and struggles of each and every shot as I looked at them. When I played the slideshow, it was absolutely clear where we'd been taken and thrilling to see how seamlessly all these surreal ideas fitted together to make such a daring and original vision, so appropriate to Susie, and so strikingly beautiful."

Bill Desowitz is senior editor of AWN & VFXWorld.