U

UCS

See User Coordinate System (UCS), and World Coordinate System (WCS).

unlabelled segment

A segment of data that has not yet been labelled to associate it with a marker. This is done during optical cleaning. Unlabelled segments display as blue asterisks.

unweighted tangent

A tangent on a function curve that does not have weight applied to it.

See also function curve and weighted tangent.

up-vector

See pole vector.

user channels

Custom channels you can create in the Character Face settings.

See also channel and Character Face.

User Coordinate System (UCS)

A user-defined coordinate system that defines the orientation of the X, Y, and Z axes in 3D space. The UCS determines the default placement of geometry in a drawing. See also world coordinate system (WCS).

See also World Coordinate System (WCS).

UV

U and V texture coordinates. U and V represent vectors in a 1 x 1 pixel image that connects to places on a 3D mesh. The U and V coordinates let you place the texture on the 3D mesh exactly. This placement attaches the texture to the object's surface, and it is mapped to create a seamless effect.