“Bats, birds, and boggans: the simulated armies of epic” by Dervieux-Lecocq, Gatenby, Adams and Bisceglio

  • ©Thierry Dervieux-Lecocq, David Gatenby, Mark Adams, and Justin Bisceglio




    Bats, birds, and boggans: the simulated armies of epic



    In Epic (2013), crowds are integral to the narrative and form a character as a whole. This required a new type of crowd at Blue Sky Studios, one that permits dynamic interaction between crowd characters and the environments around them in addition to supporting the high-resolution geometry with fur, deformation rigs, and material complexities needed for shots where the crowd is close to camera. Our crowd framework centers around the choice to separate the simulation process from the technique used to render the crowd. This meant we could use different simulators for different shots. At times, the crowd exceeded 100,000 characters, far more than in any of our previous films. To manage all this data we store only per character joint animation instead of deformed geometry. This compact format allows us to both display art direct-able representations of the crowd in real-time and to defer evaluation of the expensive parts of the rig until render time. To render the crowd with our in-house ray-tracing renderer, CGIStudio™, we build a custom, optimized deformation system that supports rendering of both deformed geometry and deformed voxels.

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