Grindhouse

While B-movie influences—from Roger Corman to the kung fu canon of the Shaw brothers—have always seeped into their films, in 2004, the two famed directors decided to combine their passion to produce Grindhouse, a blood-soaked double bill featuring Tarantino’s Death Proof and Rodriguez’s zombie horror flick Planet Terror, both linked together by a pastiche of faux movie trailers all designed to bring this bygone theatergoing experience to the masses. In recapturing the unrestrained spirit of these cheaply made films, both directors were forced to take their visual effects game in a whole new direction, aiming for a unique fusion of practical and digital effects that would both surpass and remain true to the handmade effects of the time.

For the first time, Rodriguez couldn’t indulge in the kind of hyper-stylized digital effects seen in Sin City or the Spy Kids films; instead, he and his effects house, Troublemaker Digital, along with The Orphanage and makeup wizards at KNB EFX Group, created a photorealistic hybrid of practical and CG imagery. While Tarantino continued his long-standing tradition of eschewing CGI, relying instead on KNB and unbelievably dangerous stunt work, he turned to The Orphanage to digitally clean up many of his shots. 

In Death Proof, Stuntman Mike (Kurt Russell) stalks Jungle Julia (Tamia Poitier) and two of her closest friends as they visit some of Austin, Texas’, most famous diners, such as Guero’s Taco Bar and the Texas Chili Parlor, before hunting them down behind the wheel of a muscle car called Deathproof. In Planet Terror, married doctors William and Dakota Block (Josh Brolin and Marley Shelton) are besieged during their graveyard shift by townspeople stricken with sores and bearing vacant eyes. Leading the stand against the enraged aggressors are Cherry Darling, whose leg was ripped from her during a roadside attack, and Wray, her former significant other. With a machine gun bolted to her leg stump, Cherry and Wray lead warriors into the zombie-filled night.

“Our primary responsibility [for Death Proof] was to remove various objects required for the safety and success of the practical stunts,” says The Orphanage’s visual effects supervisor Ryan Tudhope. “A number of shots required paint and rotoscoping to remove cables, stage rigs, lighting, crews, and cameras. Also, for safety concerns, Tarantino had to shoot the collision of Deathproof with a red Honda in the middle of the road, when he wanted it to occur in the lane the red Honda was traveling in. In the end, we helped out by digitally moving the yellow divider lines.”

Another example of the more understated, supportive role played by digital effects in Tarantino’s film is a shot in which Deathproof slams into the Honda and flips end over end as it careens to a stop at the end of the road. “Amazingly, the vehicle was piloted by a stunt driver,” says Tudhope. “The hydraulic rig required to flip the vehicle became visible on the underside of the chassis toward the end of the shot and required a digital ‘patch’ to cover the area.”

In all, Troublemaker completed 289 shots for Planet Terror, while The Orphanage delivered 107 for Planet Terror and 38 for Death Proof. The collaboration among the three companies was so close-knit, however, that in any given shot or sequence, it’s almost impossible to tell where one company’s work ends and another’s begins. 

Film Damage

Aside from their ultraviolent subject matter, exploitation films shared another common trait: a degraded condition. As the prints traveled across the country from theater to theater, they would accrue so much damage—from scratches and fingerprints, to cigarette burns and missing frames and reels—that it became part of the soul and character of the genre. In fact, while watching one film from his private collection that had a missing reel, Tarantino found that the narrative hole left an interesting mystery about what had happened at that point in the story. Film damage, in effect, led to unique and fascinating storytelling possibilities.   

With that in mind, Tarantino and Rodriguez invested an enormous amount of work in celluloid damage. Tarantino damaged his film organically, manually scratching, burning, and cutting the work print and living with whatever destruction he inflicted. Rodriguez, on the other hand, sought a greater level of creative control, wanting the damage to serve as an emotional punctuation for events in the story. To that end, he charged the artists at The Orphanage and Troublemaker Digital with damaging his film digitally.

The Orphanage processed one reel (number 2), while Troublemaker did the remaining five reels of Planet Terror. With rendering times averaging a few minutes per frame, and 25,000 frames per reel, it was a huge undertaking to process the entire film. To get the artists into the spirit of the genre, Tarantino invited the crew to a local theater in Austin, where he’d hold nightly screenings of his private collection of 1970s exploitation films, encouraging them to absorb the narrative nuances and celluloid aesthetics.

Both companies used Magic Bullet and Misfire, two Adobe After Effects plug-ins from Red Giant Software. Originally developed by one of The Orphanage’s partners, Stu Maschwitz, the tool set was significantly enhanced and expanded by a group led by damage lead Dav Rauch. The goal was to help the artists match the film damage references captured by animation supervisor Webster Colcord, who cut together clips from his personal library of old films and teaser trailers.

“We had all these different clips and references telecine’d, so we were able to bring them into our computer and study them frame for frame and even steal some of the scratches, dust hits, cigarette burns, tape marks, and all kinds of things that we wouldn’t have been able to come up with on our own, or with any third-party application or plug-in,” says Tudhope. “Our tool set [within Magic Bullet and Misfire] gave us a wide range of controls for adding scratches, micro-scratches, hairs, various sizes and types of dirt, flicker, fingerprints, and splotches, even light bleed from the sound strip on the left side of the frame. We also had a bunch of edge fading and saturation anomalies that we picked up from some of our references, as well as grain diffusion, gate weave, and distortion.”

Directing his digital artists, Rodriguez had a specific methodology governing the severity, location, quantity, and kind of damage he wanted throughout his film. “He was precise and patient with us as we dialed in the exact amount of damage,” says Tudhope. “There were a lot of shot-specific effects on top of all the generic ones; cigarette and tape burns had to happen at specific moments; large blotches or burns, warbling, or a splice had to correlate to the story. Our first direction from Robert was, ‘Find a look for the damage that enhances the shot and gives it some kind of life without covering up the important effects or the acting.’ So, we used the damage to support the acting and story in unique and clever ways, but never to the point where it became too obvious that it was tied to the events in the story.”

For example, if a character is stabbed by a needle, the whole frame might shake slightly and flare suddenly with a red burn, but if that person gets stabbed again by the needle, the same effect would not be used again. “We wanted to use it in places where it would surprise people but not take them out of the story,” Tudhope explains.

Along with Magic Bullet and Misfire, Troublemaker Digital also added Eyeon’s Digital Fusion to its arsenal of film-damaging tools. “The rule of thumb for us was to focus first on areas where the mechanics of the camera or the medium itself dictated damage, like at the beginning or the tail end of the film,” says Troublemaker Digital’s Rodney Brunet. “Frame flutter, fingerprint blurs, and scratches were all used sparingly until Robert [Rodriguez] or the story dictated that they be exaggerated. Robert would also use the damage to help tell the story; for instance, if he wanted to push the story along, he would just cut part of the film, using it like a film burn.”

Cherry Darling

Brunet and his team at Troublemaker Digital were also charged with erasing Rose McGowan’s leg and replacing it with the digital machine-gun prosthetic, a laborious rotoscoping and compositing challenge tackled by Drew Dela Cruz using Autodesk’s Flame. First, to scan McGowan, Troublemaker turned to Eyetronics, which used its ShapeCam scanning system to capture all the actors and props, including the machine gun, at the Troublemaker facility.

Working in Softimage’s XSI, artists textured, rigged, and animated both a full model of Cherry and another of just her leg. “In most shots, the CGI part of her was the gun all the way up to the bandage. The CG bandage was then blended into the live-action bandage, but there were a few cases where we replaced her entire leg all the way up to her thigh,” says Troublemaker’s Chris Olivia.

Because the film unfolds at night, finding an effective method of tracking McGowan’s leg in the live-action plate was a process of trial and error. In fact, the group tested a range of options, including glow-in-the-dark paint, fiber-optic, battery-powered tracking lights, LEDs, a colored stocking, and rigid casts. In the early R&D stage, artist Alex Toader wired some of those items inside a cast, but the cast proved too uncomfortable for McGowan. The best solution was to use a green stocking—just for lighting reference—and hand-track her in XSI through the shot. “So all that data we calculated early on was useless,” says Brunet. “Had she been able to keep her leg stiff, the cast would’ve worked like a charm with [The Pixel Farm’s] PFTrack or [2d3’s] Boujou, or one of those object-replacement software packages, but it was just too cumbersome and difficult for her. The bounce light from the LED and fiber-optic lights created too much spill.”           

Artists did use PFTrack and Boujou for tracking the camera, however. For Flame artist Dela Cruz, reconstituting the backgrounds to fill in the blanks around the erased leg was a constant challenge. “Once the actress was removed, we didn’t have the best information, or the lighting would change, so we’d have to look at each shot like a puzzle and just start tracking elements in the plate that we had and put them back, or make completely clean plates,” he says.

Tracking and replacing the actress’s leg in film, which was shot at night, was difficult and required trial and error.
From left: The artists worked out the scene in 3D, tracked the shot (this one using PFTrack),
and tested the digital replacement in an animatic. At right is the final frame.

Helicopter Heroics

To remain consistent with the practical effects of the 1970s, Rodriguez tried to complete all the shots in-camera, a decision that entailed dangerous stunt work throughout most of the film, especially in a helicopter sequence and another featuring a large tow truck called the Killdozer. To help plan the stunts, Olivia worked closely with the stuntman to develop the action through animatics. “For example, when Cherry has to fly over the wall, we animatic’d those shots, guiding the stuntwoman, who was then placed in a harness and lifted by a crane. Another shot, in which a police officer gets thrown into a cop car, was directed by our animatic, as well.”

Rodriguez also appropriated one of Troublemaker’s animatics directly into the film while shooting “Machete,” one of the faux trailers in which Danny Trejo rigs a machine gun to the handlebars of a motorcycle and then launches into action. “Robert ended up liking the animatic, so instead of shooting [the stunt], we just used the animatic because the camera was so far away from the actor that we were able to get away with it,” explains Brunet.

At the climax of Planet Terror, the machine-gun-legged Cherry races to a rising helicopter sitting on a tarmac, clings to a rope attached to its side, and dangles wildly beneath it as it soars away. On the tarmac set in Austin, Rodriguez used the front end of a helicopter—minus a prop and rotors—to shoot as much of the scene as possible, even lifting McGowan into the air using a crane and a harness. Completing the sequence was a team effort between The Orphanage and Troublemaker Digital.

“We created a second digital helicopter and also extended the real one, adding the props and the tail. Interestingly, our helicopter was a mix between a Black Hawk and a Sea Stallion, so it was a kind of hybrid helicopter, which is cool because it allowed us to have a bit of creative freedom over the design, which Robert ultimately liked,” says Tudhope. Modelers at The Orphanage built the polygonal chopper in Autodesk’s Maya based on photos of the real one taken on set, while artists at Troublemaker painstakingly hand-rotoscoped McGowan’s real leg and replaced it with the digital machine-gun prosthetic.

Then, using Maya, After Effects, and Digital Fusion, The Orphanage took over the plate from Troublemaker, disconnected McGowan with her newly added digital machine-gun leg, and put her on a 2D card inside a 3D environment, where they could move her around, make her swing on the rope, or make her smaller as she recedes into the distance. “The shot was very complex because we had to take over not only the motion of the real McGowan, but the motion of the real camera as well, which we had to blend with our virtual one to make it look like the helicopter was taking her out of the frame. So, it was a lot of motions that added up before it all finally came together with a bit of smoke and camera shake,” says Tudhope. For matchmoving the camera and actors, The Orphanage used Boujou and PFTrack.

For the full CG “hero” shots of the helicopter, showing it rocking and swaying under the influence of gunfire, buffeting winds, and Cherry, The Orphanage used Reactor, an Autodesk dynamics plug-in for 3ds Max.

A good deal of the action in Planet Terror was done using complicated stunt work.
To help choreograph the scenes so they would go as smooth as possible,
Troublemaker Digital created CG animatics.

The Killdozer

The second major effects sequence of Planet Terror features the Killdozer, a brutish tow truck trailing heavy metal chains and rigging. With Cherry Darling running alongside, the Killdozer careens out of control, veering off the side of the road before spinning and tumbling four times. For this shot, Rodriguez wanted Troublemaker and The Orphanage to deliver a horrible crash while still maintaining believability in the weight and rigid-body dynamics of the vehicle’s action. “It was a challenging shot,” says Troublemaker’s Toader. “She’s running next to the truck for 400 frames, meaning we had to animate and composite the gun leg with no clean back plate and no motion tracking, all the while matching the camera motion blur.”

While Troublemaker handled Cherry Darling’s animation, artists at The Orphanage worked on the Killdozer’s animation. After building a high-res polygonal model of the truck in Maya using photographic references, the team ran it through a series of dynamics simulations using Reactor for 3ds Max. The simulations gave the artists a sense of weight and mass, and what was physically possible under the conditions of the crash. Using the dynamics simulation as reference, the animators then hand-animated the truck in Maya, using a highly flexible rig developed by Daniella Calafatello.

The rig, which included IK splines for the chains, enabled the tires and axles to break apart, and allowed all the various sections of the truck to move independently so the team could vibrate the bed of the truck separately from the chassis and hood, for example. That way, the truck wouldn’t appear completely rigid as the various sections crashed under themselves. The hand-animated Maya truck passed back and forth between Maya and 3ds Max at least a half dozen times so that various parts could be dynamically animated in Reactor, such as the metal chains and rigging that swing around with the momentum of the flipping truck.

One example of the film’s perfect marriage of practical and digital effects is the blisters that spread like wildfire across the bodies of the infected townspeople. KNB applied the blister makeup to the actors’ faces, but when Rodriguez entered postproduction, he wanted the blisters to pulse and drip fluid across the face. “It was a case of the best of both worlds. We had the amazing reference of the KNB blisters already on the actors’ faces and were able to use that for lighting reference,” explains Tudhope. Using polygonal patches modeled in Maya, his crew created a series of Maya blendshapes representing the different phases of the blisters, such as blown up and deflated. By blending between them, it looked as if they were pulsing and, sometimes, bursting open.

Because the actors’ faces were constantly moving, The Orphanage’s matchmove supervisor, Tim Dobbert, built a tool for tracking the faces in 2D and applying the tracks to 3D space by locking the points on the z axis. “It was a great way of ‘match-imating’ the digital blisters to the actors’ faces and getting them to deform properly as the people talked,” adds Tudhope.

Rodriguez directed the digital artists to make the blisters feel like a ’70s makeup effect, in which little airbags may have been placed underneath synthetic skin, then blown up and down really fast to give them a sense of life. “That’s what we went for in Planet Terror. We didn’t want the effects to feel so over the top that they had to be CG; we wanted them to be more subtle, so that they may have been possible back in the ’70s,” says Tudhope.

And if the film’s melting confetti of flesh and gaping blister wounds were not gruesome enough, the bodies are also bathed in digital blood. Toader shot some of the blood practically with an HD camera, then added some of the finer spurting and splattering using Wondertouch’s ParticleIllusion, the same software he used to enshroud the night air in layers of mist, fog, and smoke.

For lighting and reflection-mapping the digital environments, both companies used HDR images of the Austin set captured from a chrome ball by Troublemaker. “We would place those HDR images in 3D space, so our CG objects reflect the same objects that everything else in the scene is reflecting. Everything, from our helicopter to the blisters on the side of someone’s face, is reflecting photographs of the set,” says Tudhope. For texturing, The Orphanage used Adobe’s Photoshop and 3D procedural textures developed in Maya.

Grindhouse is the first feature film to explore the idea of using CGI to produce hyper-realistic “retro” effects; and in re-creating the past, both The Orphanage and Troublemaker Digital were forced to collaborate more closely than ever before, forging a partnership that can only empower Rodriguez’s imagination for future projects, such as Sin City 2. “I found it helpful to call the guys at Troublemaker or visit the set in Austin so we could exchange ideas and offer input on each other’s shots,” says Tudhope. “Working with Robert is so much fun because every film he creates is really a new and unique adventure.”   Brunet echoes Tudhope’s enthusiasm about working with Rodriguez. “The cool thing about working with Robert is we all get to be generalists; we get to wear so many different hats: we’re compositors, 3D artists, we even get to write a bit of code. Sometimes that hurts us, because of the sheer volume of work we’re expected to deliver in such a short amount of time. Even so, I think we did a pretty good job.”

In viewing the end result, “pretty good” might be a mild understatement.

Martin McEachern is an award-winning writer and a contributing editor for Computer Graphics World. He can be reached at martin@globility.com.