8

1130 Glossary
World Space
A book in objec t space rests on a table in world space.
World space is the universal coordinate system
used to track objects in the scene. When you
look at the home grid in the viewports, you
see the world-space coordinate system. World
space is constant and immovable. By con vention,
world-space coordinates are always expressed
as XYZ coordinates, as opp osed to the UVW
coordinates of
object space (page 3–1076) .
All objects in your scene are located in world
space by their position, rotation, and scale (their
transforms).
Some
modifiers (page 3–1068) operate in world
space. See
World-Space Modifiers (WSMs) (page
1–498)
.
Space warps also operate in world space. A space
warpdefinesanareainworldspacethatisaffected
by the space warp ’s parameters. Any object that
isboundtothespacewarpisaffectedasitmoves
through the space war p’s area of world space.
World Sp ace ( Bip ed)
When you use freeform animation (page 3–1039)
to animate a biped, you can place a biped limb into
the space of another object, or into world space.
For example, if the biped’s feet are in world space,
then when you move the center of mass, the feet
stay planted in the same lo cation.
World-Space Modifiers ( WSM)
World space is the universal coordinate system
that applies to the entire scene. A world-space
modifier, as opposed to an
object-space mo difier
(page 3–1077)
,affectsanobjectbutusesworld
coordinates.
Aworld-spacemodifieralwaysappearsatthetop
of the
modifier stack (page 1–487) .Itseffectis
independent of its order in the stack.
See also
World-Space Modifiers (WSMs) (page 1–498)
x r ef (AutoCA D E x terna l R efer ence)
An AutoCAD external reference. An xref is a
variationonablock. Ablockisacollectionof
geometry that is identified by a unique name,
is stored in the AutoCAD symbol table, and
essentially behaves as if it is a single object. Xrefs
share block charac ter ist ics, and they are similarly
defined in the symbol table. H owever, unlike
blocks, the geometr y associated with an xref
definition is not stored in the current AutoCAD
drawing; it is stored in another AutoCAD drawing
file. Like a block, there can be many instances
of an xref in a AutoCAD drawing, but only one
definition.
Typically, xrefs are used to display the geometry of
a common base drawing in the current AutoCAD
drawingwithoutexpandingitssize.Thisallows
changes to the reference drawing to be reflected in
any host AutoCAD drawings that refer to it.