2011

transmittance scale Increases or decreases the amount of energy a transparent material
transmits out to the scene.
transparency A quantity defining how much light is let through an object.
transparent command A command started while another is in progress. Precede transparent
commands with an apostrophe.
two sided material The positive and negative normal of the material will be considered
during the rendering process.
UCS See user coordinate system (UCS).
UCS icon An icon that indicates the orientation of the UCS axes. (UCSICON)
underconstrained geometry Objects with unsolved degrees of freedom are underconstrained.
underground The XY plane of the user coordinate system when perspective projection is
turned on and when viewed from below ground. The underground plane displays with a
color gradient between the earth horizon (nearest to the horizon) and the earth azimuth
(opposite the horizon). See also ground plane and sky.
up direction A vector defining what direction is Up. By default this is the positive Z – axis
(0,0,+1).
The up direction and the north direction are always constrained such that they are
perpendicular to each other.
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).
user parameter Named user-defined variable (real number or an expression) that can be
used in expressions for dimensional constraints or other user parameters.
UVW The material’s coordinate space. Used instead of XYZ because that is usually reserved
for the world coordinate system (WCS). Most material maps are a 2D plane assigned to a
3D surface. The U, V, and W coordinates parallel the relative directions of X, Y, and Z
coordinates. If you look at a 2D map image, U is the equivalent of X, and represents the
horizontal direction of the map. V is the equivalent of Y, and represents the vertical direction
of the map. W is the equivalent of Z and represents a direction perpendicular to the UV plane
of the map.
| 1621