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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.
NURBS surface Surfaces that are have control vertices in the U and V directions. NURBS
surfaces cannot be associative. See also procedural surface and generic surface.
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 when the ObjectARX application 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 override.
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.
Ortho mode A setting that limits pointing device input to horizontal or vertical (relative
to the current snap angle and the user coordinate system). See also snap angle and user
coordinate system (UCS).
orthogonal Having perpendicular slopes or tangents at the point of intersection.
output property A lookup property whose value is determined by input properties (other
parameter properties) through the use of a lookup table.
page setup A collection of plot device and other settings that affect the appearance and
format of the final output. These settings can be modified and applied to other layouts.
pan To shift the view of a drawing without changing magnification. See also zoom. (PAN)
2664 | Chapter 52 Glossary