2004

Glossary | 853
model space One of the two primary spaces in which AutoCAD objects reside.
Typically, a geometric model is placed in a three-dimensional coordinate space called
model space. A final layout of specific views and annotations of this model is placed
in paper space. See also paper space. (MSPACE)
named object Describes the various types of nongraphical information, such as
styles and definitions, stored with an AutoCAD drawing. Named objects include line-
types, layers, dimension styles, text styles, block definitions, layouts, views, and view-
port configurations. Named objects are stored in definition (symbol) tables.
named objects, dependent See dependent named objects (in xrefs).
named view A view saved for restoration later. (VIEW)
node An object snap specification to locate points, dimension definition points, and
dimension text origins.
nonassociative dimension A dimension that does not automatically change as the
associated geometry is modified. Controlled by the DIMASSOC system variable. See
also associative dimension and exploded dimension.
normal A vector that is perpendicular to a face.
noun-verb selection Selecting an object first and then performing an operation on
it rather than entering a command first and then selecting the object.
NURBS For nonuniform rational B-spline curve. A B-spline curve or surface defined by
a series of weighted control points and one or more knot vectors. See also B-spline
curve.
object One or more graphical elements, such as text, dimensions, lines, circles, or
polylines, treated as a single element for creation, manipulation, and modification.
Formerly called entity.
object enabler A tool that provides specific viewing and standard editing access to a
custom object in AutoCAD or other host applications when the ObjectARX applica-
tion that created the custom object is not present. See also custom object and proxy
object.
Object Snap mode Methods for selecting commonly needed points on an object
while you create or edit a drawing. See also running object snap and object snap over-
ride.
object snap override Turning off or changing a running Object Snap mode for input
of a single point. See also Object Snap mode and running object snap.
ObjectARX (AutoCAD Runtime Extension) A compiled-language programming
environment for developing AutoCAD applications.
OLE For object linking and embedding. An information-sharing method in which data
from a source document can be linked to or embedded in a destination document.
Selecting the data in the destination document opens the source application so that
the data can be edited. See also embed and link.
opacity map Projection of opaque and transparent areas onto objects, creating the
effect of a solid surface with holes or gaps.
origin The point where coordinate axes intersect. For example, the origin of a
Cartesian coordinate system is where the X, Y, and Z axes meet at 0,0,0.