
It's very fitting that the marines are sent in to protect downtown LA from an alien invasion in Battle: Los Angeles --the enemy is a comparable militaristic one. In fact, director Jonathan Liebesman wanted to evoke Vietnam. For the creature work and mayhem, Everett Burrell (Pan's Labyrinth [1], Sin City [2]), the overall visual effects supervisor, called upon several vendors to complete 1,000 shots, principally Hydraulx, Spin VFX, Cinesite, Embassy VFX, Soho VFX, Luma Pictures and Shade VFX. Burrell also made significant use of a small in-house VFX team, known as "the garage band," which contributed around 200 shots, mostly tracer fire and custom tools for rifle scope POVs.
"Jonathan wanted the aliens to be faceless with no eyes, sort of like a giant sonar dish of a head," Burrell explains. "The navy has a recon plane with a big dish on top of it that orbits around and sends signals. He wanted the head to reflect that. Underneath that skin there's something else going on, which I'm sure we'll find out in the sequel. This is just a camouflage covering that they wear, but you see little glimpses through anatomical pieces of weapons and pipes and tubing. The unique thing is that Jonathan didn't want them to be a creature; he wanted them to mimic what marines look like, so you got the vibe that the marines were fighting another military force, not a fantasy alien."
Designed by Paul Gerrard (TyRuben Ellingson designed the hardware vehicles), the aliens are split into humanoid bipedal infantry types (built by Hydraulx) and floating commander creatures (built by Cinesite) with a long body and multiple legs. These weren't your typical insect or reptile or crustacean-looking aliens: they acted like soldiers.
An early test phase overseen by Burrell with the assistance of Spin, made use of footage shot at Sony (a corporate building being rebuilt looked suitably "bombed out and destroyed"). Sony head Amy Pascal was so pleased that she signaled the next phase, which included storyboarding and previs (by POV) while script revisions were made. The film was subsequently greenlit and production took place in Louisiana the second half of 2009. Post started in early 2010.

The plate was shot with three helicopters, which Cinesite (under the supervision of Ben Shepherd) enhanced to a formation of 12 by adding CG ones. The airfield was further populated by tanks, light armored vehicles and armor, as well as atmospherics such as smoke streams and distant smoke rings.
To create the massive destruction, Cinesite applied realistic smoke, dust, fire and water explosions. Physical elements shot on location were composited onto digital matte paintings. Layers of haze, smoke and dust were created in Maya Fluids and Cinesite's proprietary software, csSmoke. The donut-shaped smoke rings seen at various stages are Cinesite's trademark in the film and symbolize the aliens landing. Liebesman set Ben's team the task of creating dramatic but realistic smoke rings after the director was inspired by an explosion on set.

The freeway battle, meanwhile, was handled by Hydraulx. "It contained a lot of infantry alien [fighting] and matte paintings of LA from a freeway overpass as well as the Walking Gun, which is a very unique piece of hardware," Burrell contends. "This was based on the BigDog robot, built by Boston Dynamics. It's basically a canon with legs, and an alien would guide from behind it, firing artillery. This involved lots of tracer fire and bullet hits and matte paintings."
The final battle contains contributions from Cinesite, Hydraulx, Spin and Embassy, in which the marines discover the alien command & control center hidden underground; it unearths itself and the marines have to shoot it out of the sky to stop the signals being transmitted from the center. Hydraulx did the command & control center rising up out of the ground.

"It was a very complicated collaboration because a lot of them had to share assets," Burrell suggests. "But we warned them that the film was going to be all hand-held, a lot of zooms and roto and tracking and we had to share assets. I couldn't award it all to one company, because not one company was big enough. And we couldn't afford ILM or Weta or even Sony Imageworks, so we spent our money wisely. The most difficult part was getting vendors to match assets with one another. It certainly kept us on budget doing it this way, but it kept it hard for me and my staff to keep track of everybody."
Bill Desowitz is senior editor of AWN & VFXWorld.
Links:
[1] http://www.awn.com/articles/production/ipans-labyrinthi-partnering-make-fantasy-vfx-reality
[2] http://www.awn.com/articles/production/isin-cityi-bringing-graphic-novel-screen-literally
[3] http://www.awn.com/articles/production/igeneration-killi-recreating-iraq-photoreal-cg
[4] http://www.awn.com/articles/technology/autodesk-2012-lineup-offers-new-solutions
[5] http://www.awn.com/news/technology/foundry-ships-nuke-62-and-nukex-62
[6] http://www.awn.com/news/cg/new-pricing-pixars-renderman
[7] http://www.awn.com/news/visual-effects/new-rendering-3ds-max-and-mental-ray-training-dvd-gnomon-workshop