Optical terminology

 
 
 

Almost all optical devices, file formats, and capture systems have their terminology that refers to optical capture and reconstructing optical data. This section lists the terms used to describe optical capture, cleaning, and reconstruction methods.

Optical Root

Represented as a sphere, the Optical root is the main reference for optical data imported into MotionBuilder. You can translate, rotate, and scale all markers attached to the optical marker.

Sensor

A sensor is a reflector or light source attached to a performer’s body. Sensors are tracked by optical cameras during the capture process. Captured data is combined to create segments.

Marker

Markers are used to identify segments. One or more segments, after being labelled or identified, combine to create a marker of continuous data.

Segment

Refers to data captured from a sensor during an optical capture session. During optical cleaning, you label segments to associate them with markers. Unlabeled segments display as blue asterisks.

Current Segment

The current segment is selected in the Optical editor. When a segment is selected and active (not set to Done in the Label pane), it is colored green.

Rigid Body

Two or more markers that are grouped to correct occlusion are called a Rigid body.

Gap

A gap is the space before, after, or between a marker’s segments that do not contain sensor data.

Done

Done refers to the state of a marker in the optical system. When set to Done, the marker is no longer an active optical marker and cannot be used within the Optical settings. Done optical markers are non-active markers whose data can be filtered and modified in the FCurves window.

Sample

The position of a sensor recorded by each camera at each frame is called a sample. All samples from each camera are processed by a computer which generates a three-dimensional representation of each sensor’s position in time. These are also sometimes referred to as keyframes.

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