It may be a Hollywood disaster film, but Into the Storm’s vast repertoire of tornadoes and destruction is, at least to some degree, based on real-life reference. Here’s where three of the visual effects vendors on the show looked to for inspiration in crafting mile-wide tornadoes, fire-nadoes and airport calamity for the Steve Quale film.
Making the mile-wide tornado
The action: An enormous ‘super storm’ wreaks havoc over a school and sweeps away massive sections of a forest and anything - including vehicles - in its wake.
The reference: Method Studios, responsible for many of the mile-wide tornado shots, turned to multiple pieces of reference as starting points. “The clips we saw might represent different stages of the storm,” says Method Studios visual effects supervisor Nordin Rahhali. “Hurricane footage was very good for atmospherics and the amount of debris in the air, while there was great tornado reference that might be excellent for the edge of the tornado. Or there might be footage showing the uprooting of trees that we’d follow.”
At one point, the storm passes over the heroes who find themselves in the eye of the cell. “We saw this great reference that someone had shot from outside the tornado and it happened to bend away and break up,” says Rahhali. "It gave you a look inside the tornado which showed a clear smaller tornado in the center of this thing. Steve Quale also wanted this mini-tendrils which was inspired by real life tornadoes spinning around with secondary tornadoes almost coming off the body - which we kept on the interior.”
The solution: With such a large supercell to create, Method broke down the tornado into individual components: a tornado core, a cloud-like center, the outer shell, the supercell itself, a ground contact layer and tendrils. Surrounding environments were also augmented or created, and sometimes a CG tree system was utilized in order to show the devastating effects of the tornado.
Method relied on a combination of Maya and Houdini to craft the supercell. “We would start with a layout phase in Maya with a simple ground plane and some geometry and we’d define a rotation speed,” explains Rahhali. “Then once we had something that we felt was moving in a mass and it felt good, we could take those settings and apply them in Houdini and build the tornado with noise and volumetrics.”
The shots featuring the eye of the storm were entirely CG, with the additional challenge of having to sell a scene no-one had ever really viewed or caught on camera. To help with scale, Method added in a host of objects such as cars, buses, semi-trucks and trees.
Playing with fire
The action: The heroes chase a storm front as multiple rope tornadoes appear around them, ultimately picking up a gas truck at a car dealership and throwing it into some gas pumps - the resulting fire is sucked up into the tornadoes to create ‘fire-nadoes’.
The reference: “I personally couldn’t believe it, but there was actual reference of fire tornadoes,” says visual effects supervisor Jay Barton from Digital Domain, responsible for the fire-nado sequence. “It actually does happen in nature, not necessarily how we depicted it, but in say a forest fire where you have heat rushing up and the cold air coming from the side - that will suck in the air causing its own tornado.”
The solution: DD had to tinker with its existing particles toolset to ensure that the fire-nado did not just look like fire burning on the outside of the tornado. “We had to make sure all the various elements like dust and debris and mist as well as the fire on the ground and fire in the center were all being affected by the same wind,” notes Barton.
For that, the studio relied on Houdini’s dynamics system, DOPS. “The actual fire tornado was first simulated along a single axis to allow more control of the behavior,” explains Barton. “The volumes were transferred to point clouds, that were then deformed based on the curve geometry FX received from Animation. The point clouds were then transferred back in to a volume, and rendered in Mantra.”
“The layers of destruction filling the scene were very important in selling the look of terror,” adds Barton. “Most of the flying background debris was all particle based systems, with instanced debris geometry. The large scale destruction was all done using our in-house RBD software DROP. The models of the house and car dealership were very detailed, with broken chunks and debris modeled in to it. We were able to tag these sections as unique pieces in the sim, and then choreograph the destruction to a certain extent, revealing the broken detailed sections. All of this data was then passed back to render in V-Ray as V-Ray proxies.”
Chaos at the airport
The action: The storm causes havoc at an aiport, literally lifting planes and vehicles from the tarmac.
The reference: “This sequence was inspired by a famous tornado in Texas where these 18 wheel tractor trailers were getting blown through the air,” says Greg Strause, visual effects supervisor for Hydraulx which handled the shots. “They were getting blown so high and so far that when the camera was zoomed out, you just thought they were little specks, and when you zoomed in you realized they were these huge trailers! They were getting thrown around like they were little toys.”
The director also showed Hydraulx reference of planes being battered by strong winds that, at a certain strength, would provide lift and the planes would begin rising into the air.
The solution: “Those pieces of reference suggested to us,” recounts Strause, “that the scene had to play out like what might happen at the airport if a tornado came so quickly that no one had time to get the planes out of the way.”
The studio took an all-CG approach to the airport, crafting planes, vehicles and airport paraphernalia in Maya and rendering in Mental Ray. Destruction was carried out in Thinking Particles, with Fume FX and Krakatoa used for volumetrics effects. “The whole airport effectively gets erased off the face of the universe,” says Strause, “and then we did some aftermath destruction matte paintings showing the area destroyed.”
All images and clips © 2014 Warner Bros. Entertainment Inc. - - U.S., Canada, Bahamas & Bermuda and © 2014 Village Roadshow Films (BVI) Limited - - All Other Territories. All Rights Reserved.
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