3-D Camera Tracking / Photo Credit: Mikey Borup - Vimeo
WHAT DOES AN 3-D MOTION TRACKER DO?
(In the Entertainment industry.)
What Does An 3-D Motion Tracker Do?
Motion tracking is the foundation upon which all
live-action visual effects are built; this is the first step in creating a
match move, which allows a computer-generated object to be inserted into
live-action footage.
Duties
The 3-D motion tracker works as a member of the
visual effects team during post-production and is responsible for identifying
and tracking features in a scene that will later include CGI objects. He or she
typically works under the direction of the visual effects supervisor and a
senior artist. To begin, the motion tracker uploads a selection of footage to a
software program like PF Track. Next, he or she must determine if and where
masks should be applied within the frames. Masks, as the name indicates,
effectively hide information from the program that should not be tracked. For
example, if the scene includes an actor moving about a room, the motion tracker
may wish to hide that actor in favor of tracking the stationary furniture
within the real space.
The key task of motion tracking is setting points,
which represent 2-D coordinates within each frame. The software program uses
these coordinates to determine and track the camera’s position throughout the
scene. The artist selects stationary points within the space that represent
real objects and where there is a high degree of color contrast—corners work
especially well. Many software applications will offer the option to
automatically place points based on color contrast information. In this case,
the artist reviews the points through the progression of frames and then
deletes any errant points that are misplaced or unnecessary. The technique of
interactive tracking requires the artist to place points by hand in each frame
in order to create an effective track; this is sometimes necessary in footage
that includes a great deal of object movement or camera jitter in the sequence.
Once the points are set to the motion tracker’s
satisfaction, he or she allows the program to calibrate in order to solve for
3-D motion. Because video footage represents a series of 2-D images, the
software applies an algorithm that will make it possible to treat each frame as
a 3-D space when inserting three-dimensional objects. CGI objects will then be
augmented to reflect the camera’s movement through the scene, accurately
reflecting perspective, size, and distance relative to the camera and real
objects in the scene. The artist must also establish a ground plane that tells
the software where the spatial axis of the environment within the frame is;
this orients the virtual camera and selected points in a definite space. At
this point, the motion tracker will typically export the completed frames to a
new program like Maya where the 2-D frames are reconstructed by a match mover
to represent a 3-D environment, and the computer generated objects are placed
within the scene.
Skills & Education
A career as a 3-D motion tracker requires training in
visual effects techniques and appropriate software. A college degree in
computer animation or related field is the typical path toward employment. Visual
effects artists, whatever their specialties are, must have a solid education in
composition, lighting, perspective, and similar artistic aspects of
cinematography. While the computer lifts most of the burden of mathematical
calculations off the artist, it is beneficial to understand the algorithms at
work in the motion tracking process. The techniques of the craft are constantly
evolving and becoming more sophisticated, so the more the artist grasps of the
equations involved, the more he or she is able to contribute to the advancement
of motion tracking in cinema.
What to Expect
The role of the 3-D motion tracker is considered an
entry-level position within a visual effects studio. A rookie may be recruited
directly out of college based on his or her VFX reel or may graduate to the
role from that of render wrangler. On the job, the work of the other artists
and animators further down the post-production pipeline is dependent on the
motion tracker’s initial process; this means the artist must show a keen
attention to detail and a meticulous work ethic. A motion tracker who can
deliver clean tracks efficiently will prove invaluable to the studio, thereby
moving another step closer to promotion. Career advancement will depend on your
specific skills and artistic or technical talent, but related careers include
rotoscope artist, match mover, lighting artist, texture artist, and
animator.
Sources, References & Credits: Google, Wikipedia, Wikihow, WikiBooks,
Pinterest, IMDB, Linked In, Indie Wire, Film Making Stuff, Hiive, Film Daily, New
York Film Academy, The Balance, Careers Hub, The Numbers, Film Maker, TV Guide
Magazine, Blurb, Media Match, Quora, Creative Skill Set, Chron, Investopedia,
Variety, No Film School, WGA, BBC, Daily Variety, The Film Agency, Best Sample
Resume, How Stuff Works, Career Trend, Producer's Code of Credits, Truity, Production
Hub, Producers Guild of America, Film Connection, Variety, Wolf Crow, Get In
Media, Production Beast, Sony Pictures, Warner Bros, UCAS, Frankenbite, Realty
101, Careers Hub, Sokanu, Raindance, Film Connection,
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3-D Camera Tracking / Photo Credit: Mikey Borup - Vimeo
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