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'The Dresden Files': More Paranormal VFX Thrills

Alain Bielik investigates the demanding vfx work in SCI FIs new paranormal series, The Dresden Files.

The Dresden Files features signature vfx involving former wizard Bobs unique abilities. Keyframe Prods. creates Bobs disappearance into a skull by using both 3D and 2D fire effects. All images © NBC Universal.

You think youve seen it all with The X-Files? Think again. Premiering Jan. 21 on SCI FI Channel, The Dresden Files promises to deliver even more thrills and twists in terms of paranormal investigation than the famed Chris Carter production. The show focuses on the adventures of Harry Dresden (Paul Blackthorne), a wizard who secretly uses his unique abilities to solve cases that the Police Department is unable to handle. Advising him on his investigations is Bob (Terrence Mann), a former wizard who has been banished to live out his days as an immaterial being. Bob cannot affect the mortal world and has the ability to pass through any object.

The shows demanding visual effects were awarded to Keyframe Prods., with Frantic Films producing specific sequences for some episodes. The core team at Keyframe included vfx director Darren Cranford, on set supervisor and coordinator Clint Green, operations manager Brian Simpson and 3D leads Tito Belgrave (a VFXWorld contributor) and Paul Neale. It was decided between us that Frantic would have the most experience with 3D fire, so they took the majority of the fire related sequences, Green recalls. Knowing that Frantic had just come off of Superman Returns, we had confidence in the fact that creating fire effects in HD would not require as much R&D for them. At Frantic, Carol Cowley and Jonathan Butchard were the key supervisors.

Dealing with High-Resolution

One of the unique aspects of The Dresden Files is its HD format. The high- resolution images imply longer rendering times, but also a completely different postproduction pipeline. With NTSC, we would receive Beta tapes, digitize the footage, remove the field order, do the shot, lay the shot back to Beta and ship, Green says. Now, post-production sends us the shots on external hard drives or DVD. The HD frames are usually progressive, so logging the field orders is no longer an issue, and everything stays within the digital world. The other most significant change would be the attention to detail. We have to remember that details in a visual effect that would be obliterated at NTSC, is now completely viewable in HD. It takes more time, but we have noticed that people appreciate those little subtleties in the details.

The average vfx shot count per episode is 30-40, ranging from simple window composites to energy fields, glowing body parts and CG characters. As always on a television program, scheduling is the key to the success of the visual effects work. Once we receive a script, a vfx meeting is scheduled in the first week, Green notes. This meeting will determine the effect concepts and the plates requirements. Usually, this same week, we begin to prepare sketches, storyboards and any necessary previsualization. The second week is usually the first week of principal photography where we spend approximately every second day of the six-day shoot supervising the proposed vfx sequences. During this time, we are focusing on building any necessary 3D objects and characters, and beginning to break down the next episodes script. Once shooting has ended, it takes two to three weeks before post-production can forward the required footage, as they have to lock the edit first. Once we receive the plates, our vfx schedule is only seven to 10 days. After we deliver, the shots are cut in and color corrected. During the color correction and sound edit, we still have a little time to make any necessary revisions. Therefore, from the time we receive the script to delivering the final effects, we work on each episode for approximately seven to eight weeks.

Keyframe decided against using greenscreen to show Bobs ability to transform his appearance because it would hinder the tight six-day schedule. Instead, cameras were locked off, actors switched and a heat distortion was created.

A Streamlined Pipeline

According to Green, the key to meeting the deadline is knowing the staff and catering to the strengths of each of the individual talents. It also helps to have producers who can approve shots within 24 hours. Keyframe was also able to greatly streamline its pipeline during its three years on Mutant X, a show that had up to 100 vfx shots per episode. The pipeline is mainly based on Autodesk 3ds Max, Autodesk Combustion and Digital Fusion.

The show features several signature effects, many of them involving Bobs unique abilities. When retiring to the skull that he calls home, the character is tornadoed away in a spiral of fire that fireballs into the skull. His disappearance is created using both 3D and 2D fire effects. Bob is torn apart into a flame tornado, by first compositing him onto a blank background plate, Cranford says. Artist Richard Chiu does a rotoscope paint and gradually removes him with a soft brush erase. With the remaining plate, he uses the same brush, only this time using smear, to push Bob in the direction of the flame, which has yet to be composited in. Lighting effects are added to those pieces -- again, frame by frame. For the fire, we generally use fire plates from our library that we map to planes in 3ds Max. These plates are animated following a helix pattern around the position where Bob will appear/disappear. We then make a 3D matte of Bob to go in the center of this helix. Two passes are rendered out of this effect -- one with the matte, one without. This gives the effect a dimensional quality. The non-matte render goes behind Bob, which fills in the space where Bob no longer is, and the matte render goes on top. The two layers sandwich him, and are enhanced with glows. A separate 3D fireball is rendered to trail into the skull as the final element and composited as one.

Changing Faces

A very resourceful character, Bob is able to transform his appearance into any other likeness. This particular effect is achieved by continuing Bobs fire nature. He burns away the old self like paper, revealing the new character underneath. We wanted to have an effect that looked like paper turning to ash, or a burning cigarette, Cranford explains. We knew that this effect would be reoccurring quite often, throughout the series, and we didnt want to hinder the extremely tight six day filming production schedule by putting up a green screen each time for this effect. So, we decided to shoot with locked off cameras. Technically, we would shoot the first actor while filming with a DV camera that was supported by a video switcher that director of photography Alwyn Kumst carried. We would then remove actor #1, replace him with actor #2, line the body up with the switcher and record. Then, artist Zac Campbell made selections that grow while following the contours of the actors body. These are then filled to reveal the other actor underneath. As the effect grows, we create a heat distortion and crumple the first body to give it a decaying look as it dies away. The advantage of this technique is that two people generally dont line up perfectly, even with the use of a switcher. We then painstakingly paint the burning glow over the two people frame-by-frame. This is then enhanced by a Gods ray element to give Bob his ethereal quality.

Keyframe did use greenscreen to turn a live-action character into a full-on 3D werewolf. The actress was replaced with a werewolf model built in Cinema 4D and then refined in ZBrush.

In one of the later episodes, Keyframe was faced with a tough challenge: turning a live-action character into a full-on 3D werewolf. The first step in creating the transformation was to shoot the actress on green screen with a locked off camera. She then stepped out and the crew removed the greenscreen to grab the plate. The green screen was set up directly on stage to take advantage of the actual light from the set, thus allowing for a better composite later. The werewolf model was built in Cinema 4D by Belgrave, and then refined in ZBrush. Normal maps were created from the model to use on a lower resolution version, once converted to 3ds Max.

Texture mapping was created from the same info. Textures for the werewolf were gathered from the practical puppet that was used for some silhouette shots. We also went as far as to photograph a large dog, especially the head as reference and for additional textures, Cranford recalls. Hair was added to the model using 3ds Max standard plug-ins. Our 3ds Max rigger, Paul Neale, created a swap character rig, so that we could quickly animate the bones, then swap that out for the high- resolution werewolf, once we were ready to articulate the face. We originally planned on using morph targets for the face, but decided a face rig would give us a broader facial range. The last stage was to match move the werewolf to the actress motion, and light it appropriately. To create the transition between the two characters, artist Simon Park used Combustion 4 morph tools. Once blended properly, it was composited in the background plate.

The same process was used to create the 3D demons that often confront Dresden. The main difference was that demons were created via CG face replacements, while the werewolves were entirely CG. The faces are matched in 3ds Max with a loose eyeball track, Cranford notes. At this point, we are mainly concerned with the rotation, so we delete the position keys. We bring the rotation tracked head into Combustion, and use its tracker.

Keyframe is used to last minute vfx effects requests and are ready to tackle anything on short notice. Each week the script introduces a whole new set of challenges in terms of characters and effects. Above, Bob passes through a wall.

Challenges on a Weekly Basis

Some of the more demanding shots involve complex 3D tracking. The network requested one shot, in particular, after the entire show had been filmed. It required adding a set of 3D wings to a raven man character. The performer was behind glass doors with a lot of reflections, Green says. Also, the shot was not locked off, and another character overlaps the effect. Did I mention that the glass had wire mesh in it? It took a week to do, but we were very proud of it afterwards!

The idea was to have wings and feathers morph back into appropriate body positions on the were-raven character until he was human again. The plate was never intended to be a CG shot. What we received was a plate that was moving, out of focus in the foreground, and the raven man character that was semi-silhouetted behind a security (meshed) glass with reflections, Cranford adds. We rigged the wings with all the lead feathers attached to the skin of the mesh. That way, the base mesh deformed with the skeleton, but the feathers would fan out nicely. These were then animated and tracked to the actor. Combustion was then used to morph and color-match the pieces onto the body. The glass had as much reflection and mesh removed as we could. Then, we replaced it with our own reflections and newly tracked mesh. Lastly, the foreground character was rotoscoped out. One week later, and voilá! Two glorious seconds of raven man transformation!

Such last minute calls happen more often than not on a television show, and visual effects vendor have to be ready to tackle just about anything on short notice. Besides time, our main issue with the show is the unknown, Green concludes. Each script introduces a whole new set of challenges in terms of characters and effects. Besides the signature effects that are in almost every episode, each new script introduces new vfx concepts. Although this presents challenges, it also keeps the artists excited about the show!

Alain Bielik is the founder and editor of renowned effects magazine S.F.X, published in France since 1991. He also contributes to various French publications and occasionally to Cinefex. In 2004, he organized a major special effects exhibition at the Musée International de la Miniature in Lyon, France.