2011

Table Of Contents
adjacent cell selection A selection of table cells that share at least one
boundary with another cell in the same selection.
alias A shortcut for a command. For example, CP is an alias for COPY, and Z
is an alias for ZOOM. You define aliases in the acad.pgp file.
aliasing The effect of discrete picture elements, or pixels, aligned as a straight
or curved edge on a fixed grid appearing to be jagged or stepped. See also
anti-aliasing.
aligned dimension A dimension that measures the distance between two
points at any angle. The dimension line is parallel to the line connecting the
dimension's definition points. (DIMALIGNED)
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.
ambient color A color produced only by ambient light. Ambient color is the
color of an object where it is in shadow. This color is what the object reflects
when illuminated by ambient light rather than direct light.
ambient light Light that illuminates all surfaces of a model with equal
intensity. Ambient light has no single source or direction and does not
diminish in intensity over distance.
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.
annotation scale A setting that is saved with model space, layout viewports,
and model views. When you create annotative objects, they are scaled based
1008 | Glossary