8

Transform Managers 415
•The Transform C enter flyout (page 1–416) ,
which controls the center about which the
software applies the transform, is found to
the right of the Reference Coordinate System
drop-down list.
•The
axis constraint (p age 1–418) restricts the
transform along one or two axes. The axis
constraint tools appear on the Axis Constraints
toolbar, w h ich is off by default. You can tu rn it
on by ri ght-clicking an empty spot on the Main
toolbar and choosing Axis Constraints from
the menu.
Definitions
Cer t ain terms are used in the description of
transforms and the transform managers.
•An
axis is a straight line along which an object
is moved or scaled, or about which an object is
rotated. When you work in 3D, you use three
axes, labeled X, Y, and Z, which are oriented 90
degrees from each other.
•A
coordinate system specifies the orientation of
the X, Y, and Z axes used by a transform.
For example, in the World coordinate system,
as seen from the Front view, the X axis runs
horizontally from left to right, the Y axis
runs from back to front, and the Z axis runs
vertically, from bottom to top.
On the other hand, each object carries its own
Local coordinate system. If the object has b een
rotated, its Loc al coordinate system might be
different from the world coordinate system.
•The
transform center , or pivot point, is the spot
about which a rotation takes place, or to and
from which scaling occurs.
Using the transform managers, you can specify
any combination of axes, transform coordinate
systems, and transform centers.
Ax is Tr ipod I con
• An axis tripod appears in the viewports when
you select one or more objects, to assist you
visually in your transforms. This tripod
consists of three lines, labeled X, Y, and Z, and
shows you three things:
• The orientation of the tripod reveals the
orientation of your coordinate system.
• The location of the junction of the three axis
lines shows you where your transform center is.
• The highlighted red axis lines show you the axis
or axes to which the transform is constrained.
For example, if only the X axis line is red, you
can move objects only along the X axis.
You can toggle the display of the axis tripod in
all viewports by choosing Views menu > Show
Transform Gizmo, or by pressing the X key.
Transfor m Manager S ettings
The state of the three transform managers
(coordinate system, center , and axis constraints)
is stored with each type of transform. When you
switch from Move to Rotate to Scale, the transform
managers change to whatever combination they
were in when you last used that transform.
For example, if you click Rotate and set the
transform managers to Local, Selection Center,
and Y constraint, when you click Move, the
controls might shift to View, Pivot Point, and XY
constraint (whichever combination was set the
last time you used Move). When you go back
to Rotate, the controls revert to Local, Selection
Center, and Y constraint.
Tip: To avoid surprises, always click the transform
button first, and then set the transform managers.
If, instead, you first set the transform managers,
their settings are likely to change as so on as you
choose a new tr ansform button. One way to
remember this is always to set the transform and
managers by working from left to right on the