Runner
A runner is one of the entry level positions in a VFX studio. Their purpose spreads out across smallest and day-to-day tasks, such as delivering materials and messages between the departments, organizing meetings and schedules, making sure all the workers have everything they need, cleaning office and keeping it tidy, making tea and coffee, working with IT department to resolve any issues. They also could be interacting with the clients and setting up the conferences. In short, they serve the purpose of a secretary in a VFX company. The software they would be working on, other than of the primary interest of the role they want to pursue, are document processing software, such as Word and Excel.
As the most basic set of skills is required for this role, quite often it is a route into VFX artist roles. The ability to be in various departments allows the runner to learn about all the positions and key responsibilities from different professionals. This way they could find out which route is the most attractive and interesting to them. A runner could get a mentor from a field of their interest assigned to them, who will provide a list of training tasks and track the progress of the trainee.
Someone who is interested in starting out their VFX career as a runner would have to be quite passionate in the field, be keen to learn the key technical skills and constantly expand their knowledge. They must be hard-working, reliable, take the initiative, easily adaptable, enthusiastic and have good communication skills.
Matchmover
A matchmover artist has to literally match the move of the footage, such that it is possible to place something into the scene that moves along with the scene. In the old days it would be done entirely by hand. The job is to track the camera movements to be able to create a virtual camera on a computer, which will mirror the physical one on set in every way, including lens distortion. The main physical aspects to be taking a note of are the changes in position, rotation and scale.
They can go on the set as sometimes they would have to take measurements and physically place the tracking markers on the set as well as body and objects to be able to recreate the movement of the people, objects or other elements in CG. Those markers are then used in software such as Mocha, Maya or 3DEqualizer to track the camera movement and find the sequence of coordinate transformation in 3D scene. Whilst Mocha is a software created specifically for tracking purposes, there are instruments within the other programs, such as Nuke or After Effects. A mixture of tools and software could save time, hence a combination of those would often be implemented.
There are two types of matchmoving: 2D and 3D. In the two-dimensional version the matchmoving will only track features in 2D space and will not take a note of camera movement or distortion. It is often used for simple adjustments such as replacing an image on a screen, changing the advertisement on a billboard or simply inserting a plain image that will cover some aspect in the live action footage. However, it is the three-dimensional matchmoving that is more commonly used in the filming industry as interpolates 3D information from the 2D footage, thus allowing accurate placement of CGI elements into the shot. The motion files are further on passed onto the other departments, so that they can be used by compositor to seamlessly combine the footage.
The result must look realistic, so it is important that the footage was tracked correctly. It is always easy to spot a mistake, especially with a badly tracked footage. That is why a matchmover must be highly accurate and meticulous in their work. Having an understanding of maths and physics, camera principles, an eye for detail and problem-solving skills are essential.
Roto Artist
Rotoscope is the name of the contraption that would project the film on to a transparent easel on which an artist would physically trace over the film, frame at a time. Rotoscoping is one of the oldest animation techniques.
The role of roto artist resolves around tracing over live-action movements of the film, such that specific parts of the images could be used. They manually draw around and cut out objects from the movie frames. The resulted images, known as mattes, are wanted for the further adjustments. Roto artist works around areas where the CGI would overlap or interact with the live-action image. Additionally, they will assist with the preparation of material for compositing.
If the camera is stationary and does not have any movement in the shot, rotoscoping could involve just one frame. When there is change in camera’s position, relevant areas in every frame would be traced such that an accurate combination of CGI with the footage can be implemented. An object is traced with a set of tools inside the compositing software, such as Nuke, in order to create a new alpha channel for specified part of the footage. It must be created artificially as the footage taken directly from a camera has no alpha data.
A rotoscoping artist is advised to use the minimal amount of points in order to trace the subject. It is done such that if the outline of the matte changes a lot, the playback will not be as jittery and shacky. It is also harder to keep the track of too many points. A good technique involves finding the most complex shape the subject is in and outlining that first, in order to note how many points one would need to keep a track of. For a complicated shape, such as a hand, person, animal, it is better to separate different parts, limbs, fingers, etc. into different sub-shapes.
Roto artist must have drawing skills, keen eye for details and a lot of patience for the completion of the work. They would use graphics and painting software such as After Effects, Dreamweaver, Illustrator, Photoshop or Silhouette. There are also build-in tools in Nuke for rotoscoping.