Issue link: https://digital.copcomm.com/i/12812
n n n n Virtual Environments The Moving Picture Company enhanced its existing city-planning tools to build the mas- sive city of Alamut more efficiently. In addition, Cinesite created two digital cities in which much of the action takes place. waves sliding on top of one another created a leading edge for angled surfaces that created the illusion of sand flowing down a sinkhole. Rigid- body simulations set in motion to collapse the architecture triggered secondary animation that popped sand off colliding surfaces and poured sand from tilting shelves. And the sand simula- tions triggered dust layers. “We probably had 20 or 30 simulations,” Morris says. “We had the main flows, sand pour- ing off the edge of the sinkhole, the pile of rubble with interactive sand around the objects and spilling around the rocks, stuff pouring from the ceiling, and residual trickles of sand.” Te crew spent six months post-vis’ing the two-minute sequence to build the story, do- ing minimal simulations to get approvals on the shots before running the detailed sims. To add volumetric detail inside the falling sand, lead effects artist Alex Rothwell restructured a pre-baked, voxel-based occlusion calculation developed to create hair occlusion and deep shadows for Aslan, the lion in Narnia. “We got to the point where we could run simulations overnight, and they were con- trollable,” Morris says. Using a particle cache format that Rothwell developed, seed particles instanced into a volume of randomly spaced secondary particles produced 300 to 400 addi- tional particles at render time in, for example, the shape of a squashed sphere. Multiple layers of these squashed spheres produced an opaque surface. And, compositors used Apple’s Shake and Te Foundry’s Nuke to construct the final shots, sometimes working directly with par- ticle caches in Nuke. “It was enormously ridiculous, in a way, to design a shot as we were shooting it, but I think the result is fantastic,” Wood says. Massive City, Huge Armies Much of the action leading to the finale takes place on soundstages at Pinewood in the UK and in sets on location in Morocco, with visual effects studios extending the practical 14 June 2010 sets and creating digital environments. Twenty kilometers southwest of Marrakesh, near the humble, dusty village of Tamesloht, production designer Wolf Kroeger constructed a fictitious city of Alamut, a huge set with mer- chant stalls along narrow alleys lined with fres- coed mud walls. A 50-foot-tall palace stands in the town square, a central fountain gurgles near- by. At MPC, artists turned the set on location in Morocco and additional sets built on nine soundstages at Pinewood into the huge city. “For the Morocco set, we extended the palace up to six stories and topped it with a golden dome,” Wood says, “built a Tower of Babel-style structure, and huge environmental extensions. For an interior courtyard at the 007 stage in Pinewood, we added city streets, people, a variety of buildings running up to the palace, and the huge tower in the center. It’s a huge thing, all generated as a 3D build.” To manage such a large environment, MPC improved the existing environmental pipeline, which the studio had used for films such as King- dom of Heaven. “We’ve had a packaging pipeline in place for a while, but we did a lot of work just to lay out such a city,” says Matt Middleton, CG supervisor at MPC. “It has around 20,000 build- ings and 180,000 props.” To construct the city, a digital town planner would start with approximately 30 different types of buildings and polygonal planes—that is, patches—that defined sections of the city. Each patch could contain numerous types of structures and variations of each type. Te studio’s proprietary layout tool randomized building variations and types, placed them on the correct contours, and even added arches between houses. Te artists used the same layout tool to add prop variations for the buildings by working from a collection of nearly 60 props—carts, pots, rooftop canopies, for example, and wash- ing lines with laundry hanging from them. “We’d do a set number of cloth sims for a long frame range, say 3000 frames, but because we never had shots that long, we could offset the sims and never see repetition,” Middleton says. “Each patch might have a thousand or so buildings in it, but you don’t physically have the geometry in a scene. It’s a virtual layout. You can see representations in [Autodesk’s] Maya in an OpenGL preview.” Tus, lighting artists could preview the layout and adjust the mix of houses and buildings in real time. Alamut is the setting for a battle sequence, and during one of the shots with armies at- tacking the city, MPC created and animated 18,000 digital people, all of whom wore long clothing. Te long clothes and the flag-bear- ing soldiers caused the studio to integrate a cloth system into its tried-and-true proprietary crowd-simulation system, Alice. “We haven’t always simulated cloth in the background, but the flags looked ridiculous otherwise,” Mid- dleton says. Although the crew still used Sy- flex cloth simulations for close-up hero shots, the integrated system helped speed simula- tions for shots with large numbers of crowd- simulation agents. During the city siege, motion-capture cycles applied to the agents helped the team create shots with panicking citizens, charging armies, and an elite force repelling up and down the city walls. Te biggest crowd shot, however, was of approxi- mately 10,000 horseback and foot soldiers run- ning over a sand dune. Te animals and humans kick up sand and dust as they run, using sprites attached to particles in Maya. Te particles emit based on foot position. A second proprietary system, called Tickle, managed the Maya-to-RenderMan interface, provided preview nodes, and more. “We don’t