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indirect illumination Illumination techniques such as global illumination and final
gathering, that enhance the realism of a scene by simulating radiosity, or the interreflection
of light between objects in a scene.
initial environment The variables and settings for new drawings as defined by the default
drawing template, such as acad.dwg or acadiso.dwg. See also template drawing.
input property In a dynamic block definition, a parameter property other than that of a
lookup, alignment, or base point parameter that you can add as a column to a lookup table.
When the parameter values in a dynamic block reference match a row of input property
values, the corresponding lookup property values in that table row are assigned to the block
reference. (BLOOKUPTABLE)
interface element A user interface object that can be customized, such as a toolbar,
pull-down menu, shortcut key, dockable window, and so on.
interpolation points Defining points that a B-spline passes through. See also approximation
points and fit points.
island An enclosed area within another enclosed area. Islands may be detected as part of
the process of creating hatches, polylines, and regions. (BHATCH, BOUNDARY)
ISO For International Standards Organization. The organization that sets international standards
in all fields except electrical and electronics. Headquarters are in Geneva, Switzerland.
isometric snap style A drafting option that aligns the cursor with two of three isometric
axes and displays grid, making 2D isometric drawings easier to create.
key point In a dynamic block definition, the point on a parameter that drives its associated
action when edited in the block reference.
label block A block used to label views and details. Labels contain data, such as a title, view
number, and scale, that is associated with the referenced view. See also callout block.
landing The portion of a leader object that acts as a pointer to the object being called out.
A landing can either be a straight line or a spline curve.
landing gap An optional space between a leader tail and the leader content.
layer A logical grouping of data that are like transparent acetate overlays on a drawing. You
can view layers individually or in combination. (LAYER)
layer index A list showing the objects on each layer. A layer index is used to locate what
portion of the drawing is read when you partially open a drawing. Saving a layer index with
a drawing also enhances performance when you work with external references. The
INDEXCTL system variable controls whether layer and spatial indexes are saved with a
drawing.
2660 | Chapter 52 Glossary