Computer Graphics World

May/June 2014

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C G W M ay / Ju n e 2 014 ■ 27 ©2014 PARAMOUNT PICTURES CORP. AND REGENCY ENTERTAINMENT. to do this work," says Dave Zeevalk, 3D supervisor. "It was the basis of how we put together our most complex shots and was one of the first decisions we made. Going forward, it made the bulk of our task easier, especially later in the process when changes that might have otherwise been major were handled more easily due to this approach." A good example of how this was invaluable can be seen in Look's biggest shot in the film, in which Noah and his family walk down the aisles of bird roosts and put the flock to sleep with their magic smoke. Because of the overlapping nature of the bird roosts and the more than 1,800 hand-animated hero birds, the artists needed to find a way to put it all together, while maintaining flexibility through- out the process. "As the camera dollies across the set and the birds fall asleep in their roosts, we were faced with the challenge of how to properly seat our digital birds into the practical set. Because they were essentially crisscrossing each other during the course of the shot such that a single bird would appear in front of and behind other birds and the practical set, standard holdouts were impossible," says Zeevalk. "We relied on Deep techniques to combine the CG elements with the roto mattes that were required for the practical roosts. This allowed us to do things like pull individual birds out of the comp fairly late in the process, stay flexible with color and depth of field without introducing edge issues, and deal with the semi-transparent curtains that were present in the practical set." In addition, the artists rendered the elements with full Deep RGB and breakout passes. Normally, the approach is to render Deep opacity and shadow maps because there is less data to manage, and in most scenarios, this is enough, Zeevalk explains. But because of the volume of birds and the amount of flexibility needed, the group took a more extensive approach. "This led to huge amounts of data that we had to manage, but in the end enabled us to achieve what we set out to do," he adds. Birds of a Feather Because of the large variety and volume of birds that were needed, as well as the required efficiency, the Look team opted to build its own feathering system, which comprised a feather creation tool, a grooming tool, and a deployer. "Early on, we realized that we couldn't use a traditional hair or fur system because of the randomness with which points were distributed across a surface," explains Zeevalk. "Due to the fact that the layout of feathers across a bird is not com- pletely random, as hair is, we looked for other ways to apply our feathers." The artists ultimately adopted a blue-noise pattern as a basis for their distribution, whereby every point on a surface has a scale that represents the scale of that feather, and its distance to its surrounding neighbor feathers is based off that scale. They then wrote a blue-noise solver that would apply those points on a surface and then resolve spacing issues. Multiple techniques were used to instance those feathers. The feathers themselves were a series of cards that were created using a photoreal feather-creation tool built in- house. This separate application allowed them to define shape, length, and other attributes, starting with a flat, oval-shaped, low-resolution feather. They were able to push points around until they were happy with the general shape of the envelope, at which point the tool would generate the rachis along the spine of the envelope and spawn hundreds of curves to repre- sent the barbs. The artist had fine-grain control over splitting, curl, noise, and all the other various attributes that define the look of a realistic feather. The end result was then made into a texture to speed up rendering, as there were too many birds to directly render the curves of every feather. For grooming, the artists interactively painted maps on the birds, which enabled them to control a wide range of feather attributes, including scale, base color, tip color, lift (how much a Look Effects creates a new flocking and feathering system to generate thousands of birds that appear in Noah By Karen Moltenbrey ■ LOOK EFFECTS CREATED custom feathering and flock- ing systems for the birds in Noah. VIDEO: Go to "Extras" in the May/June 2014 issue box .com .com

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