C

C3D: See Coordinate 3D (C3D).
camera: A device for viewing and recording scenes. Each camera sees the scene from a different angle or “vantage point”.
camera interest: Also referred to as a look at point, the focal point of a camera, represented by a null.
Cg (C for Graphics): A high-level 3D graphics programming language developed by NVIDIA^® and Microsoft^® designed to provide the ability to programmatically control the shape, appearance, and motion of objects rendered using graphics hardware. Broadly, this type of language is called a shading language. However, Cg can do more than just shading.
Cg programs can perform physical simulation, compositing, and other nonshading tasks.

Cg uses the CgFX interchange format (.FX format).
CgFX: A standardized text-based file format for representing complete effects and appearances.

As they did with Cg, Microsoft and NVIDIA collaborated to develop the CgFX format. CgFX files are text-based, with a syntax that is a superset of Cg's, and may contain any number of Cg programs. The .fx suffix identifies CgFX files. A CgFX file describes the complete render state for a particular effect: multiple passes, texture states, and any number of individual vertex and fragment programs may be defined to create a complete appearance or effect.
channel: A digital effects processing path for video.

A particular signal path.

MotionBuilder uses channels to connect Actor Face assets with Character Face assets to create expressions for 3D models.
Character: See Character asset .
character animation: The process of animating objects or models to give the illusion of personality, life, and character. In contrast to other types of animation, objects are meant to appear alive and to appear to act on their own accord rather than to move randomly.
Character asset: In MotionBuilder, also referred to as the Character. The link between a motion source (such as an Actor , a Control rig , or another character) and a character model .

See also model .
Character Face: In MotionBuilder, the shapes on a face model which can be driven with live input, recorded motion capture data, devices, and constraints.

See also shape .
Character mapping: The process of creating a link between a data source and a 3D model with a skeleton.

See also Character asset .
character model: In MotionBuilder, a 3D object composed of a skinned model with a skeleton.

You can animate a character model by linking it to a motion source via a Character asset.

See also model , skeleton , motion source , and Character asset .
child: A model or element that is placed below another in a hierarchical structure. For example: Marker2 is parented by Marker1. In the hierarchical structure, Marker2 is the child and Marker1 is the parent.

See also hierarchy and parent .
chroma key: An effect that lets you sample out a colored background, and replace it with something else, such as a video layer.
chrominance: A portion of the video signal that contains color information (hue and saturation). Video picture information contains two components: luminance and chrominance.

See also luminance .
clip: Each individual instance of animation, audio, commands, constraints, videos, or camera shots in the Story settings.

A portion of data cut off at a defined boundary.
cluster: A collection of vertices that can be linked to objects.
cluster shapes: A shape made of cluster groups by translating, rotating, and scaling the clusters for use in the Shapes Mapping pane.

See also Character Face and cluster .
color burst: Also referred to as a burst, a reference for establishing the picture color (hue).
color timing: The synchronization of the color burst phase of two or more video signals. Ensures that no color shifts occur in the picture when the signals are mixed in a switcher or another video device.
COM port: Also referred to as a communications port, a connector for a communications interface.
combiner: A device that controls the way two or more channels work together. It determines the priority of the channels (which picture appears in front and which ones in back) and the types of transitions that can take place between them.

See also channel .
command clip: A clip that lets you show and hide models at specific frames in your track. You can also use the Command clip to launch an external application.
communications port: See COM port .
constrained object: An object whose movement is determined by the behavior of another object, using a constraint.

See also constraint .
constraint: A restriction of the behavior of one object (constrained object) based on the behavior of another object (source object).

See also constrained object and source object .
constraint clip: A clip that lets you select, blend, and fade constraints throughout your track in the Story window. To obtain the correct result, the Constraint track must be placed below the animation the constraint is meant to affect.
contrast: Along with brightness, a property that determines the luminance of an object.
Control rig: A data source that allows you to create and alter character animation using a combination of an IK rig and an FK rig.
Coordinate 3D (C3D): A public domain file format that stores 3D coordinate information, analog data and associated information used in 3D motion capture data and subsequent analysis operations.

The essential idea behind the C3D format is that all 3D coordinate and numeric data for any recorded measurement is stored in a single file, together with the various parameters that describe the data.
cross chrominance: Also referred to as cross color, moire or rainbow effects in encoded video pictures created when the video encoder misinterprets luminance detail as color information. For example, moire effects on pin-striped clothing.
cross color: See cross chrominance .
current segment: The segment of optical data that is currently selected in the Optical editor. When a segment is selected and active (not set to Done in the Label pane), it is colored green.

See also segment .
custom keying group: Also referred as custom keying mode. A set of user-defined properties that define a character’s effector (or an object) in 3d space which will be captured when a keyframe is created.

A custom keying group can be either: global (can be applied to any character or object in a scene); local (only ever applies to the object(s) that are selected at the time the keying group is created); or object (can be applied to any object in a scene).
custom shader: See shader .
cut: A section of a take’s animation.

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