Motion Control Freaks: Becoming the Fly on the Wall
By Tom Wilson

Above: Motion control rig. Photo courtesy of Pacific Motion Control, Inc.

Ever wanted to be a fly on the wall? What if you watch a story unfold from the perspective of a moving, probing fly? Motion control allows the filmmaker to tell a story from a multidimensional perspective.

Motion control can refer to something as simple as attaching a camera to a rig and controlling it with a computer for precise macro photography on a small insert stage, or as elaborate as going from an explosion of a miniature building on stage, then to the actual building on a remote location, and then back to a green screen stage to shoot the actors. Once all of the passes are layered together everything appears to be shot in one place at the same time. Motion control assures that every movement of the camera can be repeated precisely and exactly the same each time.

"If I had to pick one," says Craig Shumard, owner of Pacific Motion Control, when asked if he thought if there was a quintessential motion control shot, "I would say the shot in 'Secret Window' starring Johnny Depp."

The film used several different aspects of motion control. To start the sequence, the camera panned over a lake and "flew" up to a window of a cabin on location. Next, the crew had built a duplicate cabin on stage, with a platform outside of the window for the motion control rig. They took the tracking data from the live action footage and imported it into software. Once the rig on the stage was in position they performed a "hook-up shot." Once inside the cabin, the crew switched to a Zebra rig to continue the shot, which took the camera from the second floor to the first. On the first floor, they shot Depp playing two different characters in the same scene with a circular dolly move. "It beautifully integrates reality, non-motion control shoots, and computer graphics in one seemingly seamless motion control shot," says Shumard.

The Evolution of Motion Control

The first large-scale use of motion control was for 1969's "2001: A Space Odyssey." The camera took a series of duplicated shots and, with each pass, the lighting and other aspects of the set were changed to create the required look.

In the 1970's, movies like "Star Wars" integrated motion control with miniatures. Miniature models were used for scenes with flybys and dogfights, and motion control was utilized to duplicate camera movement for separate shots of explosions, lasers and enemy ships. The shots were then combined, or layered, to create a composite shot.

By the 80's, live action was integrated more often and motion control was shot on location. Rigs were taken outside and actors were more involved in the shots. It was around this time that computer graphical (CG) elements were integrated. When CG was introduced, filmmakers initially thought miniatures were no longer necessary.

Slowly, CG began to take the place of miniatures, matte paintings, and different lighting effects. But, according to Shumard, computer graphics alone wasn’t always believable. "People are so used to CG they think everything is CG but a fair amount of it is motion control, or a combination of the two," says Shumard.

The role of CG expanded greatly in the 90s. It was not uncommon for a filmmaker to spend six months shooting on a stage using motion control. Think "Titanic", "Armageddon" and "Dante’s Peak."

Today, live action motion control continues to be popular. In movies like "Dr. Doolittle 2", a tracking shot was duplicated three times. On the first pass, Eddie Murphy walked with a dog and the camera move followed them. The exact move was then played back with a bear walking by himself. Then a "clean pass" would be shot with no one in it. When all shots were put together the resulting image was of Dr. Doolittle walking along with a dog and a bear.

The Real World and the Reel World

Presently, the motion control model integrates all elements including miniatures, computer graphics and live action.

And the motion control process has increasingly become live action friendly.

"The equipment has become so portable and reliable that we can go almost anywhere. Every axis of movement on the camera crane, along with the camera head and lens, can now be encoded. The camera op, the dolly grip, the crane operator, all can now utilize pan/tilt wheels, pan bars, and other remote controllers in the motion control process. Everything can be remotely controlled, recorded live, and precisely repeatable," explains Shumard.

With computers programs like Maya, a filmmaker can set up a motion control shot by positioning a virtual camera and rig within a computer-generated 3-D environment. Even the dolly tracks can be laid out in this virtual world. Then the exact same motion control shot is set up in a real world environment and the two are combined. With all these advances in computer technology, the possibilities for the future of motion control will now be limited only by the imagination of the filmmaker.