Hercules Gs to Battle

Hercules is legenary for his power and strength. But, when it came time to face Rhesus in battle, even the mighty Hercules needed the help from a team of digital artists at Cinesite, who helped set the scene with CG horses, soldiers, and more in the MGM/Paramount Pictures release.

The film, starring Dwayne Johnson in the title role, is directed by Brett Ratner, with VFX supervision by John Bruno and Dean Wright. Cinesite's Visual Effects Supervisor was Simon Stanley-Clamp.

Having completed his legendary 12 labors, Hercules (Johnson), the Greek demigod, has his life as a sword-for-hire tested when the King of Thrace and his daughter seek his aid in defeating a tyrannical warlord. In Cinesite's 180 shot sequence, Hercules and his mercenaries have been hired by Cotys to help defeat Rhesus. The two armies meet in battle.

In one early shot, as the camera flies over the empty battlefield, we see Mount Asticus (a matte painting) rearing up in the background, before a massive army of charging marauders emerge over the brow of the hill. Led by soldiers on horseback, the soldiers kick up layers of dust, which rise up into the air. This challenging shot was entirely computer-generated.

The battle takes place in a region surrounded by forest, mountains, and cliffs on all sides, which were added by Cinesite's environment team. The forest was created using the Speedtree system, and in-house techniques were used to project digital matte paintings onto geometry to create environments that gave realistic parallax during camera movement.

According to Stanley-Clamp, all the environments were created based on supplied art department reference. VFX Supervisor John Bruno wanted apparent depth but also wanted the environments to remain sharp and not look painted. We needed to make sure the environments worked from multiple angles; the sun direction changed on a per-shot basis, usually between east and west, he says. This meant that two versions of each matte painting needed to be worked up, lit from each angle. Production decided we should light for the shot, not the scene, [therefore] there was no necessity to maintain continuity in the sun direction.

A traditional matte painting approach was used to create the northern environment. For the east, however, Speedtree was used to generate a small forest for one principle shot, and assets from that forest were used in about 15 other shots. For the south, the group projected matte paintings onto geometry to give multi-layered depth and parallax. For the west, Cinesite inherited a model of the cliff, which the artists remodeled and reworked, retextured, and added their own Speedtree models.

As Stanley-Clamp points out, the only way to really achieve a forest such as the one depicted is to use Speedtree. In total, the artists incorporated approximately 25 types/species of trees, which created more diversity within the digital forest.

In order to achieve the appropriate atmosphere, we had to create the right look for each direction: north, south, east and west. Therefore, we had a key shot for each look, no matter which direction the camera was facing, says Stanley-Clamp.

Versions of the artists' cliff were used in multiple shots from multiple angles. Massively oversized (scanned) sky plates were also used for the range of shots needed.

Various effects were then added, including flames, smoke, dust, straw, and grit, mainly using Autodesk's Maya and Maya Fluids. We had to create more layers of dust that were kicked up by the footfalls of the armies and horses on the dusty floor. Straw was also added to the ground, kicked up by horses' hooves, to add dynamism and impact to their movement, Stanley-Clamp says.

One hundred extras were digitally expanded to create up to 10,000 CG soldiers. Motion-capture footage of a variety of soldier actions was captured by Centroid, whose data was attached to the Cinesite rigs. A combination of stand-alone and crowd animation techniques were used to create the final, epic shots. Digital horses were also added, as well as weapons and VFX elements, including the dust and flames.

The horses were hand animated in Maya.

Over the course of the 180-shot battle, hundreds of soldiers are killed, and for continuity purposes , it became necessary to create a dead-body pass. So, one of the final shots in the sequence was created first - the one that had the widest spread of bodies on the ground. We marked their position and worked backward to introduce the bodies in the appropriate shots, Stanley-Clamp says. The same system was used with the arrows, which needed to be seen to land and remain in the correct places in subsequent shots.

A certain amount of shot sculpting was also required to relax bodies, cloth, hair, limbs, and so forth for the dead bodies on the ground, on a per-shot basis.

The continuity of battle was the most technically challenging of the work, notes Stanley-Clamp. We had to make sure the dead bodies, arrows, and so forth were in the same place in every shot and every angle to further increase the realism. Complicating this was the fact that there were very few greenscreens on set, he says.

With so much CG in the scene, the artists had to maintain a level of realism to the sequence. As Stanley-Clamp explains, this was done by matching live action with what the group was trying to create through good, consistent lighting and HDRI in each shot. Also, the use of good textures helped further increase the sense of realism through the battle.

In all, nearly 80 people at Cinesite worked on the sequence over a four-month period.

LINK:	http://www.cgw.com/Press-Center/In-Focus/2014/Hercules-Goes-to-Battle....
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