Ghost Rider - Technical Production Notes

Creating believable CG fire as never seen before was only the beginning for Kevin Mack and his Sony Pictures Imageworks visual effects team, working with director Mark Steven Johnson on “Ghost Rider.” The film’s challenges in bringing a comic book hero roaring to life have resulted in effects that break entirely new ground.

The Columbia Pictures action-adventure “Ghost Rider” is based on the popular Marvel Comics superhero, in which motorcycle stunt rider Johnny Blaze (Academy Award® winner Nicolas Cage) makes a deal with the devil in order to save his father’s life, only to find himself possessed by a demonic alter ego, Ghost Rider. As he struggles against his new identity, he must save his girlfriend Roxanne (Eva Mendes) and engage in a mortal battle with Mephistopheles.

When Visual Effects Supervisor Mack, an Academy Award® winner for the landmark effects in “What Dreams May Come,” first met with director Johnson, Mack’s take on the film was straightforward: “I always felt that comic book movies are most effective when they’re treated realistically.“ says Mack. “Treat things a little under the top, because the story is a bit over the top.” Johnson agreed. For a film whose title character is a flaming skeleton who rides a Hellcycle and battles demons composed of wind, earth and water, that was probably a good place to start.

Sophisticated as visual effects have become, even the filmmakers were hoping that they could find, build and master the technology that “Ghost Rider” would require. The visual effects Johnson envisioned, by his own admission, “couldn’t have been done five years ago.” When asked how important the effects are to this film, Johnson is blunt: “They pretty much make or break this movie. We had budgeted it and everything was good to go, except that we didn’t know if we could do it,” he says with a chuckle.

Mack’s initial idea was to create a highly realistic simulation of fire using computational fluid dynamics through Autodesk’s Maya program, which includes a canned fluid solver. Digital Supervisor Ken Hahn, a comic book film veteran through his work on the Academy Award®-winning “Spider-Man® 2,” quickly put together a test with input from a few additional artists. Rudimentary as that early trial was, says Hahn, “when I showed it to Kevin, he immediately saw that it was the image that would lead us down the path we needed to take.” Positive reaction from Johnson, Cage and the studio “was really encouraging,” says Hahn. ”It got everyone really excited about it, which is what you need.”

The team then needed to build on that foundation to achieve Mack’s vision for a character that was totally believable despite being a supernatural being who can defy the laws of physics.

Since “Ghost Rider” has 300 shots in which CG fire was prominently featured, Mack brought in Dr. Patrick Witting, who has a PhD in fluid dynamics from Stanford, to head up the fire team. Witting had experience creating fire in Dreamworks’ animated film “The Prince of Egypt,” and Disney’s “Reign of Fire.” Says Witting, “We knew that it was a whole show full of fire. With a main character on fire, there was going to be a high degree of scrutiny over it and we needed a pretty robust set of tools for really getting the fire exactly where we wanted it and doing the things we needed.”

Witting’s big hurdle in the R& D phase was setting up a workable fire pipeline. Says Mack, “Patrick insisted that our only chance was to build the proper pipeline. There was still an artist setting them up in a handcrafted way, but there were so many stages beyond that, it had to be streamlined.”

Ken Hahn says, “It wasn’t as easy to implement as everyone hoped. It rarely is, especially when you’re trying to do new stuff. We really struggled to get those first fire shots out the door.” Witting and 4 other “real smart folks,” as Mack calls them, constructed a system which had control aspects in Houdini, flowed into Maya for the solver computations, and then went back into Houdini for driving the render setup, with a lot of custom-written glue to hold it all together.

The estimated six months became nine. As Johnson says, “I kept asking, ’Kevin, when am I going to see that first fire shot?’ and Kevin’s response was always two words: ‘Fire’s hard.’ He’s a great artist himself, and he’s not big on showing things that are really rough. But I’m thrilled with the final product. It looks beautiful, and I think there’s stuff here that people haven’t seen before, which is the best compliment you can give any artist.”

“Patrick and his team got the fire doing things we never thought we’d get,” says Mack, who likens the endless parameters they faced in making the fire behave to “playing Battleship, you know, just trying something.” Johnson’s vision was that Ghost Rider’s fire, a rich inextinguishable layer flowing over his skull, was supernatural Hellfire, which was clean-burning, cool to the touch – “It becomes hot when it leaves his body,” explains Johnson – and a bit slower than actual fire.

Another technical challenge was balancing the exposure of the CG fire elements. CG Supervisor Brian Steiner says, “We realized if we made the skull darker instead of brightening it, it actually looked better, and you could see the detail and colors of that fire better if we cheated the fire a little darker. In reality, it’d be just the opposite.” Balancing their resources was also an issue, since the computer systems used to do the various levels of rendering on “Ghost Rider” required more disk space than any previous production at Imageworks, according to Witting.

Another element Mack wanted to incorporate into the shoot was interactive light, the reflective flickering light Ghost Rider’s supernatural fire would cast on his clothes and other surfaces. At Mack’s suggestion, it was shot as a practical element with Cage and his stunt double wearing a battery-pack operated collar covered with wafer-thin LED’s, which would emit glowing, irregular light that cast onto the characters shoulders and environment. We used the same technique on the wheels of the Hellcycle. “We felt it would be harder and more expensive to put all the interactive light in post, so the idea was to get some interactive light in the plates,” says Mack. “It was no magic bullet, but it gave us something to work with.”

A tour de force sequence which stretched the length of the 18-month visual effects schedule was Johnny Blaze’s first transformation into Ghost Rider. A spiraling steadicam shot, it starts with Nicolas Cage writhing and twitching as his face and hands steam, smoke and redden; hot spots break out and his skin burns away like parchment paper, revealing the clean skull of Ghost Rider underneath. “It was just brutal,” says Mack, shaking his head. “All the shader work to burn his skin away, all the simulation… it’s a very gradual process. There were dozens of systems for doing flicks of flame and embers and smoke and fire, and it was really hard. You get the 3D as close as you can, and then a lot of it had to be hand tracked by the compositor.”

Animation Director Marco Marenghi had his own fish to fry, so to speak. “It was a big, big challenge to us as animators to pull off lip synch with no lips,” he says. “It was just a jaw wagging, so our approach to lip synch had to be modified from what we would do with a conventional character.”

Director Johnson says, “When you’re dealing with a skull, you don’t have anything that gives a person expression, so we needed the fire to do that for us. That was a real creative endeavor from the guys to show his different moods with different colors, like when he’s angry it’s a white-hot rage, or when he’s with Roxanne it becomes blue. We also needed to make it an extension of his personality in the way that he moved.”

One solution, Marenghi says, was animating in subtle gestures. “OK, let’s roll the jaw here, put an inflection in the head that wasn’t there on the performance when he would hit certain consonants, in the absence of facial expression,” he says. Another aspect that helped the dialogue synch issue considerably was the fire sim, which was actually generated from the finished animation file.

Witting says, “The skull was used as a collision object for the fire, so when his mouth was open, the fuel coming out would react to his speaking and it just naturally gave some reaction to it.”

An animator who prides himself on “creating realistic movement,” Marenghi jokes that the real reason he was on the show was “I had 28 years’ experience riding motorcycles. I had a particular interest in making sure the motorcycle rigs behaved correctly, and that we could create realistic motorcycles.” He and some of his animators regularly rode motorbikes to work, but in trying to explain bike mechanics to a non-riding rigger, Marenghi finally said, “Right, guys, I’m booking a couple of dirt bikes, I’m taking you up to Gorman and I’m going to teach you six guys how to ride motorcycles,” which made the film’s producer and Sony’s lawyers nervous. “I had to clearly say, ‘This is not a Sony sanctioned event,’ says Marenghi puckishly. “But it made an enormous difference in their animation.” The motorcycle club’s popularity grew to 24 people by the end of the post.

Once they had the static fire shots looking great, the really hard stuff became creating fire that was reacting to a motorcycle ride, helicopter rotors, even fire burning underwater. As an example, Witting says, “The fire sim was parented to Ghost Rider’s head, and if he’s shaking his head violently back and forth, the thing the fire would want to do was create a cone going straight up. The fire wasn’t reacting at all, so we built counterforces into the mix to create motions that would make the fire react appropriately. And Steve Marshall, who was on our fire team and then went on to do water interaction, did a fabulous job of getting the bubbly surface and how the water reacts to the fire when Ghost Rider’s underwater. He definitely sells those shots.”

One effect which was crucial to the fire reacting to speed was what are called “tear-offs, the bits of fire that break away,” says Mack. “We thought we’d just get those, but they turned out to require a lot of extra effort, like having fuel waiting in the air to be ignited as the thing got to it, all kinds of bizarre tricks, but in the end, it was just beautiful.”

For the “Ghost Rider” visual effects crew, the director’s appreciation for their talents created an atmosphere of rare creative collaboration. “Everybody at Imageworks is so smart,” Johnson says. “They’re a great combination of really intelligent scientists and crazy artists, and I’ll take a great idea from any of those guys.”

One such opportunity was when Johnson wasn’t happy with a shot in which Ghost Rider breaks through a parapet on top of a skyscraper and drives straight down the side of the building. Johnson asked Mack to come up with something with more pizzazz, and Mack handed it over to Marenghi, who in turn presented the challenge to animator Maks Naporowski. “Maks did this fantastic shot where Ghost Rider drives off the building, and it goes into slow-mo and he whips his chain round and lassos the building and pulls himself back in, and then goes down. It was all Maks coming up with the content, and Mark absolutely loved it,” says Marenghi. Says Johnson, “It was a radically different idea, and it was so much better. Those are the moments that show the genius of those guys.”

Mack is also known for creating an open environment. “I try to empower the artists to contribute creatively, because that’s where the magic happens,” he says. Hahn agrees, saying “Because of the flexibility the production gave us – and Kevin’s a very open-minded visual effects supervisor – a lot of the artists had that freedom to give their input on how to improve shots.”

Adding to the complexity of the effects were the elemental demons known as The Hidden, who are the henchmen of arch-villain Blackheart. Each character had a scene in which they battle Ghost Rider and had associated complicated effects, but they were more minor characters, which meant it didn’t make sense to create a pipeline for each one. Mack describes them: “Wallow, who’s able to form out of water and transform into water at will; Abigore, who is the wind elemental demon, so he can become the wind and fly around. He’s solid but with little wispy bits like he’s somewhat ethereal all the time. And Grestle, who can form out of swirling bits of dirt.”

These characters were done with a mix of 2D and 3D effects, says Ken Hahn. “It just goes to show you don’t always have to do everything in 3D. Sometimes you can just do some raw image manipulation and have it be very effective.”

Across the board, the sequence that makes the “Ghost Rider” visual effects team most proud is the Desert Ride, an all-CG shot of Ghost Rider racing through the desert on his motorcycle, alongside the Old West Ghost Rider on his flaming horse. Says Mack, “Mark wanted a beautiful Southwestern kind of look, so we created this huge desert with tumbleweeds and plateaus and monoliths. Matte painter Martha Snow Mack, my wife, did this matte painting which had surrounding landscape as well as the sky, and it’s designed in such a way that we can angle it around to see night with moonlight, or as you come around, hints of glow on the horizon.”

Marenghi says, “It looks fabulous. The environment, the light, the flames – you’re just there, riding with them. The fact that it’s all CG, that we can take an entirely generated piece and drop it into the middle of a live action film and pull it off, I think speaks volumes for this company and the team that created it.”

The overwhelming feeling at the end of production was that they had delivered more than the filmmakers had asked for – and had fun doing it. Witting says, “It was hard work but very fulfilling, because so much was riding on it. I feel like the fire stands up with any other fire that’s been done, and surpasses it in many areas.” “It was a blast,” says Marenghi. “It doesn’t become work, it becomes fun, and I think that’s why the stuff looks as good as it does.” Director Mark Steven Johnson puts it best when he says, “I’m the biggest fan of these guys. Every time we got together to look at new stuff was like Christmas.”