Issue link: https://digital.copcomm.com/i/739236
20 cgw s e p t e m b e r . o c t o b e r 2 0 1 6 was assigned," says McLean. Furthermore, Stratasys' bundled printer soware limited how those three colors could be mixed – a problem for Laika, which had grown accustom to painting detailed, gradated textures that could be jetted down onto a powder substrate. Still, the new plastic polyjet technology was so proficient at printing – with unfailing repeat- ability the fine feature details of Monkey's face and fur, the Moon Beast's lamellar body, and the sharp nose and hard facets of Beetle's armor-like head – that the benefits far outweighed the drawbacks. The RP team's only challenge was color matching the conceptual art. To that end, Laika bypassed the bundled soware and had expert 3D printing engineer Jon Hiller develop custom slicing soware that would allow for gradient shading and fine color details. Hiller's new driver could output a giant 3D bitmap that told the printer where to place each microscopic droplet of cyan, magenta, yellow, black, white, or clear resin in the exact proportions to replicate the color of the digital model. Hiller also improved Stratasys' color model by equating and indexing specific ratios of 3D resins with their real-world measured color. "The final hurdle was con- vincing Travis [Knight] that the faces of Monkey and Beetle could be simplified to three colors," says McLean. Initially, there was some fear that the subsurface scattering of the Z650 powder-based humans might seem incongru- ous next to that of the res- in-based creatures, by the way light reflected, refracted, and raked across their faces (the Z650 printer jetted down color a sixteenth of an inch into the powder substrate). The fear proved unfounded, however, when they discovered the UV-cured resin of the polyjet technology was inherently translucent. The subsurface scattering of Monkey and Beetle has a similar quality to Kubo, even though they're made out of plastic. M A K I N G F A C E S The Connex3 produced thou- sands of high-resolution color sculpts for Monkey and Beetle, providing over 13 million possi- ble facial expressions for Beetle and 30 million for Monkey. In total, 15,581 faces were made for monkey on the Connex3, while 23,197 were printed for Kubo on the Z650. No matter the printer used, the head-modeling process always began with scanning a clay maquette into Autodesk's Maya. Then, modelers refine the topology in both Maya and Pix- ologic's ZBrush before sending it to the printer. Aer incorporat- ing subtle artistic changes from Knight, the modeler simplifies the geometry in PixelMachine's Topogun and decides where to split the mouth and brow, while riggers outfit the face with sim- plified facial controls for shaping the expressions. Working in Maya, the CG modeler then collaborates with the fabrication lead to engineer the internal components for the head. "This means [Laika's modelers] have all the problems of modeling for a CG production, along with a myriad of concerns stemming from creating a phys- ical object: minimum material thicknesses, printer resolution, mechanical tolerances, and so forth," says Lead 3D Modeler Ty Johnson. "The majority of a mod- eler's time is spent breaking the head into over 70-plus mechan- ical parts that have to fit into the head the size of a golf ball." Because 3D printing files have always been polygonal, Laika's RP department has found Maya perfectly suited for handling both the so- and hard-mod- eled geometry, and ensuring they function together. Next, a small group of digital animators fashion the vast dig- ital library of expressions used throughout the film. Then, ani- mators are assigned shots in the film, for which they pull shapes from the pre-existing library or create special expressions and send a Maya Playblast of the facial performance to the edi- torial department. If approved by the director, the CG animator compiles the list of faces for the shot, requesting pre-printed expressions be pulled from the physical face library and sending the special expressions off to the 3D printer. Once printed, the faces are cleaned, sanded, and tested before delivery to the stage on the day of the shoot. Because Knight was demanding such a finely pitched acting style, tending to these "special expressions" became an almost unending occurrence. "On Coraline, our job was creating different phoneme shapes to string together for lip syncing," says McLean, "but over the course of the last few films, it [became more] about very subtle acting and getting as much emotional range from these little puppets as possi- ble. We'd provide Travis with Playblasts, and he'd kick them back with acting notes asking, for example, for a slight tilt in the brow. Our pipeline wasn't designed for this level of scruti- ny. It was designed for building a library of hundreds of faces in advance that could be delivered to the set and reused over and over. So sometimes we didn't have the correct expressions in the predetermined kits, which forced us to go back into Maya, and animate and print faces especially for the shot." In keeping with this push for greater emotional range, a face was no longer animated every other frame, like on ParaNorman, and instead changed expressions 24 frames per second. Moreover, the animators shaped the main THE INTRICATE, HARD-EDGE DESIGN OF SOME OF THE CHARACTERS, SUCH AS BEETLE (ABOVE), REQUIRED NEW 3D PRINTING TECHNOLOGY.