Fri 2nd Aug 2013, by Paul Hellard | Production

All images © Twentieth Century Fox. Supplied by Rising Sun Pictures.

CGSociety :: Production Focus

1 August 2013, by Paul Hellard

Rising Sun Pictures (RSP) created 266 VFX shots for The Wolverine, the new action film for Twentieth Century Fox. As part of the formative early sequences, Seventy-five RSP artists helped to recreate the World War II atomic bomb attack on Nagasaki in Japan. They also produced digital environments for a scene set in a snow-covered Japanese village, and combat effects such as digital copies of Wolverine’s iconic claws for use in numerous scenes involving challenging stunts. The work was conducted under the supervision of the production’s VFX Supervisor Philip Brennan, and VFX Producer Jamie Stevenson.

“RSP was one of the primary vendors on The Wolverine," says Stevenson. “Having worked with them in the past, we knew they would be a great fit for much of the claw work, but we also felt that they were the right vendor to take on several of the key sequences that required extensive environment work as well as challenging simulations and particle effects." RSP’s team was led by VFX Supervisor Tim Crosbie, whom was also VFX Supervisor on the second unit for the 'ice village' sequence.

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Nagasaki bomb

“The view of Nagasaki, seen from across a harbour, required an extensive digital matte painting,” notes Crosbie. “We started by modeling the bomb after photographs of the actual blast but James Mangold wanted something unique and so pushed the blast into something never before seen. We were able to leverage research we had done for previous destruction effects to make an event that is much, much bigger and more immersive. It’s exciting stuff.”

Rising Sun Pictures worked meticulously to recreate the detonation and blast effects from the viewpoint of just across the bay from the Nagasaki explosion in August 1945. Tim Crosbie and spoke about the challenge. "There was a brief from Jim saying he wanted something a bit different. He said he knew the stock footage of the mushroom cloud that we all have seen. This was to show the initial blast, the flash, the dome of flame," he said. In Wolverine, the director also wanted there to be a deep interaction between a reconstruction of that event and the players in the movie. "Our goal was to generate something that the director responded well to, as well as being able to iterate it quickly," explains Crosbie. "The explosion almost became a character to escape from." Youtube: 'Trinity and Beyond'.


RSP built a detailed 3D model of the prisoner of war camp based on a location outside Sydney, and then blew it apart as the radioactive shock waves rolled through. One of those waves carries Wolverine through the air. He lands in a stone well where he uses his body as a shield in saving the life of a Japanese soldier. “Components of the huts and wood that fly past the camera required a fair amount of choreography and numerous iterations to get the action beats just right,” recalls Crosbie. “Equally challenging was the pyroclastic cloud—the leading edge of the explosion—which sweeps across city and the water and through the camp ripping up buildings, guard towers and everything else in its path. Our team did a fantastic job.”

In the initial few seconds of the detonation, this is seen from across the bay from the relative safety of a WW2 prison camp. The highest viewpoint on the sequence is the grandstand view of the prison towers.

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"When you run a simulation of an explosion, you can set all the starting conditions, but you can never tell exactly what you get at the end of it. Sometimes, you'll get a bit of serendipity and something you didn't expect, and you may be lucky and like it." Creating a presence that large, you need to load a vast amount of resolution to catch as much detail as possible. This will also take an enormous time to render out. "Clearly we couldn't get an off the shelf solution for the whole sequence, but we did use Houdini for the explosion and built a lot of tendrils upon it," explains Prema Paetsch, FX Lead at RSP. "We did have an off-the-shelf mushroom cloud simulation, and changed a lot of the framing and timing but we soon found that we couldn't just run a simulation for days." The RSP crew eventually ran a particle system which was driven by that initial mushroom cloud simulation and ran a set of smaller simulations which would be part of the pyroclastic motion around the base of the initial explosion. That way, they were able to create enough of the visuals, at the right resolution, volume, scale and detail. "This ended up being quite manageable and the simulation times could all be parallelised because they were independent, pyroclastic featurees that we could run and iterate on all at the same time," he adds. "Using some smart instancing, to distribute these, pre-cached, into the particle system of the master simulation."

Generating the extra, smaller impacts and explosions of the many buildings and superstructures on the ground at the base of the bomb was the next challenge. But also, the background matte painting of the Nagasaki environment and backdrop was another main challenge. Paetsch created a ring shaped particle system that would emminate out from the centre of the explosion. This would have that pyroclastic look, triggering explosions along the way. "We were to make sure to have the matte painting of the city, dated and true to the city's appearance at the time," said Crosbie. "In the closer shots, there was a very simple ground-plane, with a nod towards the architecture of the time. Since pyroclastic clouds do move extremely quickly, especially straight after an explosion of such scale, while it needed to show foreground superstructures, even if it was only for a few frames."

One of the signature shots of this sequence is of Logan (Hugh Jackman) surfing a pyroclastic wave into a well, shielding a Japanese soldier from the full flame force of the explosion at the bottom of the shaft. Overall VFX Supervisor Phil Brennan had a Japanese POW camp built down near Botany Bay, south of Sydney. This was where they shot a lot of the background plates for the sequence. "From this, we had a clean background, some practical elements and a green screen plate.," explains Crosbie. "We took the LiDAR scan, broke that down and rebuilt all the geometry that existed for the scene, to a level where we could then blow them up, using the Bullet physics system in Houdini." RSP started off using projected textures from the clean plates, which worked for the builds that were relatively far away, but they needed some of these pieces to fly towards camera. Several ignition points were employed to cheat more pieces of debris to fly towards camera instead of heading off to the sides. The shock wave's effect itself was created using fast fluid sims and some particle sims as well, running along the geometry based on that LiDAR. This was all based on the pyroclastic work that the team had done in the previous shots across the bay.

Rising Sun pulled together a vast amount of elements, compositing the shock wave effects together. "If the crew was careful placing these elements together, the sense of scale of complimented successfully," notes Crosbie. "We had the full team running on this, and everything was bedded in. The more stuff that's in there, as long as it is working the right way, you get that much higher level of details, and that's what sells the sense of scale."

"If you can see what we did, then we haven't finished yet."



Temple fight sequence


The Japanese Village scene, where Wolverine is attacked by an army of bad guys, also required extensive visual effects enhancement. The Japanese gardens sequence where the fight ensues between Wolverine and the others, was shot down at Darling Harbour in Sydney. The Chinese gardens were modified, and city background and the many elements that made up the Chinese flavour of the garden were switched to resemble a Tokyo city garden. "Almost every shot required claws for Logan," explains Crosbie. "We built the scan of Logan and based on that we have a bunch of rigs for digi-double and reformatted that to fit Logan, which we then used for match moving him. We could have just built a set of claws and match moved them into place, but it is easier to match move when you have the whole person. That way, you know the elbow lines up with the wrist, so it works with the angle of the blade, down from the knuckle." The models for the knuckles are then shared around to the other studios on the job, in case WETA, Method and Iloura Digital Pictures.

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The cinematographer on The Wolverine was Ross Emery, with a stellar history working on the Matrix trilogy, Superman Returns, Killer Elite and the immense Don't be Afraid of the Dark. With regards to the Castle sequence, there was a a lot of claw work in that for RSP. Being quite a dark sequence, the crew had to get the lights absolutely right. Crosbie speaks of the large number of HDRI sets they took of that set. "Another focus of that sequence was the arrows in Logan's back, with the ropes off the back of them" he adds. "We ended up using a plugin in Maya, to get the ropes bouncing behind them. Quite a challenge match-moving job, because we were match-moving Logan as well, as well as the ropes and arrows.

Live action was shot on a partial set built in a Sydney car park. RSP extended the set considerably with CG buildings, mountain ranges, and a digital version of a lab, and sprinkled it with snow. High, wide-angle views of the village are fully CG. Artists also created the torrent of arrows with ropes that are fired by ninjas at Wolverine in order to subdue and bind him. “The process involved identifying each of the ninjas and determining when each would fire,” Crosbie explains. “We match-moved a detailed CG model of Wolverine and used that to drive the arrows, rope dynamics and choreography of the scene. Once we knew where the arrows were coming from and going to, it was straightforward for the animators to work out the timing and hit their marks.”

Tim Crosbie acknowledges that some of the sequences may seem like a simple process. They researched for weeks, and laid down a pipeline on how to build the assets.  For RSP, their goal was to follow what Tim likes to call the 'Six Ps', which is, what he calls, "Prior Preparation Prevents Piss Poor Performance."

Digital replacements for Wolverine’s claws were used in place of practical claws for scenes involving dangerous stunts. In those instances, actor Hugh Jackman wore stubs or tracking markers that served as guides for match-moving the digital claw assets. “Philip Brennan provided us with a full HDRI set for every shot requiring visual effects, so we knew exactly what lighting was required,” Crosbie notes.

“That worked extremely well. Each claw was rendered out with an option of blood stained or cleaned, so at a moments notice we could make a scene gory or safe.” For the poison in the bucket, one of the RSP artists Timmy Lundin came up with an extremely clever way of creating layers of deforming geometry. "I don't think in the end he used any form of physically based simulation," adds Paetsch. This potion was supposed to look really evil: something you wouldn't want to go near, let alone drink.

"The whole visual creation is built on lots and lots of layers of deforming geometry to look like layers that crack and fall down, while building fluid and smoke rising up. While the shot of really hard, he was able to generate so many colourful layers. This emulated the best of the worst in nasty, acidy, goop. It was super challenging because it had to be better than the practical bucket effect that's been shot."

Logan walks out of the woods in one of the first sequences in the Wolverine movie. Set in the forests and valleys of the Yukon in Canada, the matte painters and environment guys at Rising Sun excelled in creating the most accepted vista backgrounds which are instantly accepted as the real deal.

They used stills, a little moving footage, all put together very nicely. Another shot to watch out for is the Nagasaki city aftermath. Based on the newsreel footage and bringing much of the destruction into relief, there was a whole swathe of reference pulled in from online. Nick Pill, the RSP Art Director found a front page image, possibly from The New York Times, which showed the initial explosion, before it rose to become the mushroom cloud.

Building these compelling digital environments is part of the core work that Rising Sun does for their slate of movies lately. Their work on immense environments for 'Gatsby', then back into this equally historic document show the breadth of skills available to them.  “We really appreciated how efficiently RSP handled the workflow for the show overall,” adds Stevenson. “No matter what we threw at them, we never ruffled their feathers. Even last minute adds and changes were all accommodated with a positive attitude.”




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