"Fast 8" broke global box office records on its first weekend, overtaking even “Star Wars. The Force Awakens”. With each new film, the creators of the franchise have chosen to use more and more exotic locations. In this installment, the mind blowing chases take place on the surface of the frozen ocean. RENDERU.COM spoke to Digital Domain specialists who worked on the Russian submarine chase sequence - Victor Grant (FX Lead), Jay Barton (VFX Supervisor) and Nick Cosmi (texture lead).

RENDERU.COM: You worked on Furious Seven before - I guess visual effects must be getting more complicated in every new film from the Fast and Furious universe. What was new and enhanced this time, and did your experience on the previous movies help?

Jay Barton: For the Fast movies each film has to up the spectacle over the films that came before. Not only the effects, but the locations have to be even more exotic and unbelievable. While the complexity of the effects and their integration, with the stunt work and plate photography is a challenge, so is the sheer volume. Shooting on a frozen lake as a double for the frozen ocean was great for the dynamics of the cars. The stunt work on the ice was really impressive and allowed great interaction with tires and ice but ultimately required us to touch almost every shot in the third act exteriors to get the type of ice and environment we wanted. Absolutely our experience on FF7 helped this time around. Having worked with the production supervisors, Mike Wassel and Kelvin McIlwain, meant that we were already up to speed with what the visual language that defines the Fast and Furious universe.

RENDERU.COM: Could you tell us about working with director F. Gary Gray?

Jay Barton: The majority of our work was with the stunt teams and the 2nd unit director had minimal direct interaction with F. Gary Gray. That being said, he was constantly providing us with reference imagery and ideas for the landscape and type of visual impact he was looking for.

RENDERU.COM: In your opinion, what was the most challenging aspect of the submarine chase sequence?

Jay Barton: The part where the submarine rises up from under the ice and multiple vehicles are trapped riding on top was known internally as the “rollercoaster sequence”. There was a tremendous amount of back and forth between our Maya animators and our Houdini FX team. A base sim was done to get the ice breaking across the top of the sub but in order to get the vehicles to have proper interaction with the ice chunks we would have to sim, reanimate, sim again in order to have the action that we wanted but with the ice affecting the cars and the cars affecting the ice. Once we had the performance and secondary interaction the way we liked, it was all exported to Maya where all the hard surfaces could be rendered in VRay. Liquid, snow and volumetric passes were then simulated and rendered in Mantra within Houdini.

RENDERU.COM: Can you tell us in detail how you created the Russian submarine, the submarine base and its environment?

Jay Barton: There is a surprising amount of information on the internet about the Akula class submarine. Unfortunately some of it is contradictory. At some point we had to take some artistic license with the design. There were missiles and hatches necessary that do not exist on the real sub, it had to match up to a set piece of a partial sub used for actor interaction and the director wanted the tail section of the sub to look more aggressive. Design and modeling was done in Maya. For texturing and surfacing I defer to our texture lead, Nick Cosmi.

Nick Cosmi: All of the textures for the Akula, were created in Mari, from photographic sources, and a wide assortment of hard surface elements. Lots of traditional projection painting was used for the barnacle elements, the aged surface, and many additional hull details, and all of the snow was created from texture painted masks. There are two unique layers of displacement that I sculpted in mudbox to get the hull warble, and built up barnacle crust. The Akula had 4-5 lookdev looks, snow covered, dry, wet, and icy. The Akula had roughly 80 patches, it had 8 standard support channels, 2 sculpted displacement passes, and additional 15 rgb masks for extra material control in lighting and comp. An estimated grand total of around 2000 maps, some scenes used additional shot specific upres textures also, pushing that total.

RENDERU.COM: Tell us about one the most interesting stunt you created in the sequence.

Jay Barton: For me it was the initial submarine breach. It started with the SPFX team, lead by J.D. Schwalm, setting up a huge under ice explosion that blew 3 real vehicles, ice and water high into the air (shot in glorious slow motion). The trick here was to animate a submarine and simulate additional ice chunks and water spray as well as replace the whole ice surface to sell the interaction between the plate action and a 700 ton submarine.

There is no easy way to put a CG submarine in the middle of such a dynamic volumetric practical plate so it required us to make a CG version that was almost identical in order for the submarine to emerge from within and push it out of the way. There was also quite a bit of secondary effects for the ice chunks that come crashing down, the ice sheet buckling under the submarine’s nose as well as ocean water sloshing up form between the sheets of ice. It is one continuous action over 4 or 5 shots that took a lot of people over many disciplines to accomplish.

RENDERU.COM: Some specialists predict that ‘practical effects’ will soon be back in fashion. Digitalartsonline writes: “Audiences are still craving movies with a heavy practical half.” What’s your opinion on this?

Jay Barton: The most fashionable thing in filmmaking is (or should be) telling a compelling and engaging story. Good movies will always have an audience no matter what genre or film making style. Personally I believe that a mix of photography with stunts, practical FX and VFX will give the most realistic, yet art directable, result.That said there are stylistic choices and budget restraints that can lead to any single or mix of strategies imaginable. While I love working on huge VFX productions, there’s more than enough work out there across all genres and budgets.

RENDERU.COM: How did you create the water simulations and destructions?

Victor Grant, FX Lead: The approach we took for the breaking ice was pretty standard Houdini destruction for the first pass (voronoi fracture and activation near sub). Once we received approval on the base sim though we ran it through our up-res setup. This would create secondary fractures around the sub or cars where needed. Finally we ran an edge up-res on all the chunks and passed that to lighting as vr-meshes. The flip sims were run after the ice sims and were a little tricky. Most of the shots started out with regular flat tanks that were tweaked. The collision transparency setting in the Houdini flip solver saved us a few times with some of the more violent and chaotic shots.

RENDERU.COM: How long did you work on the film? How many shots were created by the studio? And how many people were involved?

Jay Barton: I was involved in the show for 14-15 months from some of the pre shoot scouting through the final delivery of post production. We had assets and shots in production here at Digital Domain for 10 months and had over 300 people work on the film over the course of that time. The final total of shots delivered was 773 in addition to special trailer shots and DVD extended cut shots.

RENDERU.COM: Which software did you use?

Jay Barton: We primarily use Maya and ZBrush for modeling, Mari for texturing, VRay for hard surface rendering, Houdini and Mantra for FX and volumetric rendering and Nuke for Compositing and environments.

Images: Digital Domain http://www.digitaldomain.com/