I recently discovered a great video that actually demonstrates how the 360-degree / slow motion effects in The Matrix – such as bullet time – were achieved. The video is actually one segment (“Cinema Magic”) from a show called the MHTV show, which originates from Central Michigan University. In the segment, the hosts set up a bunch of cameras to show in real time how the effect is achieved. It’s very interesting, and the video is only a little over 4 minutes long – so put on your Matrix sunglasses and give it a quick watch right now!
To create the bullet time effect in the actual movie, 120 cameras were used by lining them up side-by-side in a precise placement. Using all of these cameras was necessary because each camera captured a different angle of Keanu’s body – by switching from 1 camera to the next, the effect of time slowing down in a 360-degree motion was achieved.
The hosts of Cinema Magic did their own experiment to create this effect. In this case, 12 cameras were pointed at an actor standing in front of a green screen, which enabled a 50 degree revolve rate (instead of 360 degrees as shown in the movie). In order to make sure that all 12 cameras were properly distanced from the center point in front of the green screen, the hosts of the show used a super long headphone cord as a measuring device. This level of precision was necessary because even one camera being a centimeter off could create a skipping or choppy effect. It was also necessary to ensure that each camera recorded at the same exact frame rate and resolution.
Before the actual filming commenced, the actor was instructed to do a clap in front of the green screen, a preliminary step necessary to synchronize every camera in time before the “real” filming commenced. This preliminary step helped ensure that the footage flowed smoothly no matter which camera was used. Next, a snapshot was taken by all 12 cameras, with each snapshot 1/30th of a second after the previous one, which helped to construct the revolving effect around the actor.
Another step in the process is called “morphing,” which facilitates a seamless move from one camera to the next. Basically, when changing from 1 camera to the next, a noticeable jump occurs in the picture, and hence morphing is used to smooth out and/or eliminate these jumps after the filming is complete. This creates the illusion that all the cameras are just one camera making a large revolution. The final step involves removing the green screen and replacing it with the actual imagery slated to appear in the film.
As you can see, creating this effect is a complicated process, but when done correctly it can really be eye-popping. Even the simple demonstration with 12 cameras produced a truly awesome effect. My only beef is that the actor, who was supposed to be Neo, was not wearing Neo sunglasses! But that nit aside, the video is still a terrific watch and as such is highly recommended. Enjoy!