2013

alpha channel
Alpha is a type of data, found in 32-bit bitmap files, that assigns transparency
to the pixels in the image.
A 24-bit truecolor file contains three channels of color information: red, green,
and blue, or RGB. Each channel of a truecolor bitmap file is defined by 8 bits,
providing 256 levels of intensity. The intensity of each channel determines
the color of the pixel in the image. Thus, an RGB file is 24-bit with 256 levels
each of red, green, and blue.
By adding a fourth, alpha channel, the file can specify the transparency, or
opacity, of each of the pixels. An alpha value of 0 is transparent, an alpha
value of 255 is opaque, and values in between are semi-transparent. An RGBA
file (red, green, blue, alpha) is 32-bit, with the extra 8 bits of alpha providing
256 levels of transparency.
To output a rendered image with alpha, save in an alpha-compatible format
such as PNG, TIFF, or Targa.
angular dimension
A dimension that measures angles or arc segments and consists of text,
extension lines, and leaders. (DIMANGULAR)
angular unit
The unit of measurement for an angle. Angular units can be measured in
decimal degrees, degrees/minutes/seconds, grads, and radians.
annotational constraint
Dimensional constraint used to control the size of the geometry as well as
annotate the drawing.
See also parameter constraint, and dynamic constraint
annotations
Text, dimensions, tolerances, symbols, notes, and other types of explanatory
symbols or objects that are used to add information to your model.
annotation scale
A setting that is saved with model space, layout viewports, and model views.
When you create annotative objects, they are scaled based on the current
annotation scale setting and automatically displayed at the correct size.
524 | Glossary