Mocap
The process of recording the data from human movement so that it can be used for 3D characters created on a computer. Mocap can be used for 3D animations for film, TV and games, and for special effects work. There are wireless, magnetic motion capture systems, and optical systems, which track markers attached to the animator.
Performance Capture
The recording of a performance, either human or animal, using a Motion Capture system (or similar technology) - difference being that you can motion capture a table, but it is cannot give a performance. Special Effects Blue (or Green)
Screen
A system that replaces a specified colour (blue in this case) with images from another source. This can either be done optically (eg. using film) or electronically (eg. in video, also known as Chroma-Key in video). Some computer systems look at pixel in the scene and determine whether to replace that pixel with the other video source. Better computer systems allow 'some' of the colour of the pixel from 1 image and 'some' from another image. The better systems could be take transparent objects (eg. bottles) or smoke and combine these with the images from another source.
Chroma-Key
Keying out parts of an image which contain a particular colour (or colours). Eg. replacing a blue or green background with images from another source.
Composite
To combine two or more individual images onto one piece of film by photographic or digital means. Early compositing was accomplished in the camera by masking part of the scene when filming, rewinding the film and removing the matte and shooting again to expose the previously masked portion. Digital compositing is commonplace, in which multiple film images are scanned into the computer, combined digitally, and output to a single piece of film.
Motion Control
Controling the motion of a camera or special effects object (eg. model space ship etc), using commands from a computer, so that the exact moves can be repeated as many times. This makes it easy to composite it (ie.combine it with another shot).
Rotoscoping
Drawing around something in the frame so that an effect can be applied to that part of the film. If an animated creature has to go behind something in the live action piece of film, that object can be drawn around so a matte can be created, so that the createure will not show over the top of that object. If the camera is moving, then each frame of film would have to be rotoscoped. If the camera is still, then the same matte can probably be used for all frames in that shot. Rotoscoping was first used by the Fleischers for making cartoons. The Fleischers invented the Rotoscope, which is a device for projecting live-action film on to paper frame by frame, so that the outline could be traced and used as a guide for the animation. The Rotoscope consists of an animation camera and a light source (usually using a prism behind the movement and the lamp house attached to the camera's open door) that projects a print through the camera's lense and the projected image is then traced to create a matte. The lamp house is then removed and the raw stock placed in the camera and the drawings are filmed through the same lense that projected the image. The resulting image will then fit the original image if the two strips of film are run bi-packed in the same projector movment (using an optical printer). In digital film effects work, rotoscoping refers to any drawn matte, as both images can be seen compisited while the matte is being drawn, so good results can be achieved.
Virtual Sets
Sets which are generated (at least partially) from data within a computer. Mostly used for TV work, these systems replace the real set (eg. an empty studio) with a computer generated set, allowing the actor/presenter to move in the foreground. eg. the background is 'keyed out' and replaced with the set which has been created in a 3D package (eg. Softimage or 3D Studio Max), and any camera movements will be duplicated by the 'virtual camera'. This will require a powerful computer, especially if it is to be done in real-time, for example a Silicon Graphics machine. The method of keeping track of the camera movement (so that it can be duplicated in the 3D computer set) is different for the various sytems. Some systems use a blue grid painted on the back wall of a studio of a known size. A red LED is projected onto the cameras and the actor/presenter so that they too can be tracked throughout the set.
Visual effects (also called optical or photographic effects)
Special effects achieved with the aid of photographic or digital technology, occurring after the principal photography, or main shooting, of a film. Includes miniatures, optical and digital effects, matte paintings, stop-motion animation, and computer-generated imagery (CGI).
Wire Removal
Removal of unwanted wires, rods, etc. from a piece of film by replacing them with what would have been seen if they weren't there (eg. the background). This can be done by replacing them with the same area from another frame in which the wires/rods were not visible, or by averaging the colours on either side of the wire and replacing it with the average.
Y-H Lee
A Motion Capture Assistant of Inner Esteem Motion Capture Studios
