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494 Chapter 8: Modifiers
The transforms of an object are expressed as
a matrix of values that contain the following
information:
• Position of the object center in world space
• Rotation of the object in world space
• Scale of the object along its local axes
The matrix is called the transformation matrix,and
its information relates directly to the transforms
Move, Rotate, and Scale. Applying one of these
transforms alters the values in the t ransformation
matrix.
Transforms have the following propert ies. They
are:
• Appliedtotheentireobject.
• Independent of their order of application. No
matterhowmanytimesyoutransforman
object, the results are stored as one set of values
in the matrix.
• Applied after all object-space modifiers have
been evaluated, but before the world-space
modifiers. See Using the Modifier Stack (page
1–502).
Most transforms produce equal displacement
along one or more axes of an object, or part
of an object. For Move (page 1–439), Rotate
(page 1–439),andUniform Scale (page 1–441)
transforms, the displacement is equal a long a ll
threeaxes.Whenyourotateabox,allsidesremain
parallel. In general, all vertices keep the same
relative position to one another. The exceptions
are Squash (page 1–442) and Non-Uniform Scale
(page 1–441), which displace axes by diff er ent
amounts.
Tip: Use the XForm modifier (page 1–959) if you
wanttotransformanobjectataspecificlocation
in the stack (that is, after some object-space
modifiers but before others), or if you want to
transform a sub-object selection. See Modifying at
the Sub-Object Level (page 1–506).
Modifiers
Most modifiers allow you to perform operations
on the internal s tructure of an object in object
space (page 3–982). For example, when yo u apply
a modifier such as Twist (page 1–876) to a mesh
object, the position of each vertex of the object is
changed in object space to produce the twisting
effect.
Modifiers can operate at the sub-object level, and
are dependent on the internal structu re of the
object when t he modifier is applied.
Modifiers have the following properties. They are:
• Applied to a l l of an object or par t of an object
(using a sub-object selec tion).
• Dependent on the order of application.
ApplyingaBendfollowedbyaTwistproducesa
result different from applying a Twist followed
by a Bend.
• Displayed as individual entries i n the mo difier
stack,whereyoucanturnthemonoroff,and
change the order in which they’re applied.
Some modifiers operate in world space. These
use world-space coor dinates, and are applied to
the object after all object-space modifiers and
transforms have been applied. Otherwise, they
havethesameoverallpropertiesasobject-space
modifiers.
Tr ansforms, Modif iers, a nd Object
Dat a Fl ow
Once you have defined an object, 3ds Max
evaluates changes affecting the base object and
displays the result in the scene. What these changes
are, and the order in w hich they are eva luated, is
called the object data flow.