U

UCS: See User Coordinate System (UCS) .

See also 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.