Issue link: https://digital.copcomm.com/i/552848
42 cgw j u ly . a u g u s t 2 0 1 5 To this end, the terrain in "A Boy and His Kite" consists of all geometry – no matte paintings, notes François Antoine, lead technical artist who assumed the role of asset supervisor on the project. The world has creatures that live in areas [of the environment] where they should, and gather where they should. It is entirely lit with dynamic lighting, contains ray- traced shadows, and features fully direct and indirect global illumination, and the lighting can be changed to reflect any time of the day or night. "Nothing is baked in," he says. The film features cinematic depth of field and motion blur. Moreover, there are trees, rocks, and vegetation everywhere – PBR (physically-based ren- dered) photo-modeled assets placed procedurally with rules. According to Libreri, one of the biggest challenges of the project was the large-scale environment creation. "We had many people working on the open world – the LOD manage- ment, the procedural foliage and forestation," he says. An intelligent procedural process within Unreal Engine handled the foliage. As a result, vegetation does not grow well in areas of the canyon where there is not a lot of light. Says Antoine, "We used a new rendering technology – distance field ambient oc- clusion," which traces cones against mesh distance fields to determine the sky visibility and how dark it should be. The engine, in fact, enables a plethora of cutting-edge achievements. It is used as a sandbox, with various tools and capabilities available – a physics system, animation system, lighting system, layout system, terrain management system, AI, camera-accurate depth of field, motion blur similar to what is used in visual effects, new global illumination techniques for bouncing light off the ground, and more. And now these func- tions are available in Version 4.8 of the engine. G E N E R A T I N G A S S E T S According to Libreri, the theme for the terrain in "A Boy and His Kite" is from the Isle of Skye in Scotland. Because the crew was working on a reduced schedule, they began researching the area virtually, using Google Earth. Then they started breaking down the components: cliff faces, large rocks, vegetation, small rocks, medium rocks, terrain rocks, ground dirt, and so forth. As it was December, the heavy rains and early darkness made an asset shoot there im- practical, so a two-person team instead headed to New Zealand, where the vegetation was lush and green and the landscape similarly varied and enticing. The photographs were used in two manners: for reference only and as photogrammetry for 3D meshes and 2D ground. For the latter, the group used Canon 5D Mark IIIs to acquire full panoramic pictures, as well as Canon 24-70mm cameras. "When we found an asset we wanted to capture, we started with a reference picture in its natural setting. Then we used a chrome and gray ball setup on a rig to capture the light intensity, and got a 360-degree HDR pan- orama," explains Antoine. This was no quick feat – they shot 30,000 photos in seven days to cover 250 assets total- ing 1 tb of data. A team of 10 art- ists across three Epic sites then reconstructed the data. "We were sending a massive amount of data across the network for each asset – between 7 gb and 45gb," says Antoine, noting that a new process was required to facilitate the transfers. Depending on their prefer- ence, modelers used either The Foundry's Modo or Autodesk's Maya/3ds Max to generate the film models. Lighting, layout, camera work, effects, and AI all occurred within the engine. EPIC'S "A BOY AND HIS KITE" IS A TECHNOLOGY DEMO AS WELL AS A DIGITAL SHORT FILM RUNNING IN REAL TIME AT 30 FPS.