This
effect is amazing to watch! In one commercial, a horse stops in mid-air and the
camera pans around it. In "The
Matrix," the technique is used just four different times,
but it is so startling that it leaves an impression over the entire movie.
In the commercials and
in "Lost
in Space," a simpler technique is used. A collection
of still
cameras (for example, 30) is set up around the object. At the
moment when the action should freeze, all 30 cameras fire at once. The images
they capture are played one after another to show the rotation.
In the movie "The
Matrix," the filmmakers use an extremely sophisticated technique to
accomplish much more advanced effects. Not only does the rotation occur, but the actor
is also moving in slow motionduring the rotation (see the first link below
for three extremely nice full-motion demos). At least five different
special-effect techniques are combined to create the final image:
·
A
large number of still cameras capture the scene, but they fire sequentially
around the actor rather than all at once.
·
The
cameras shoot the actor on a green-screen background (see How Blue
Screens Work for details on this technique).
·
The
actor is wearing a wire suspended from the ceiling so that he can fall only
part-way or appear to float in mid-air.
·
Once
the scene is shot, software similar to morphing software interpolates between
the images to allow the slow-motion feel. The filmmaker can therefore slow down
or speed up the action at will.
·
Computer-generated
backgrounds are then superimposed onto the film.
If you watch the videos in
the first link below, you will see that the images that the still cameras
capture are very rough. The wire is visible, as are all of the other cameras in
the scene. A technician deals with all of these imperfections one image at a
time using a computer and digitized versions of the images. Once the still
images are perfect, the morphing software interpolates between them. Then the
background images are laid into the green area. A technician has to build a
complete 3-D computer model of the
computer-generated scene and then key the rotation through this scene to the
position of the camera in each frame of the film.
