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14 Chapter 1: Getting Started with 3ds M ax
The expression you enter is evaluated, and its
result is displayed in the Result field. Click Paste
to replace the field value with the result of the
calculation. Click Cancel to exit the Expression
Evaluator.
The expressions you can enter are described in
Expression Techniques (p age 1–141) .Youcan’tuse
variables in the Expression Evaluator, but you can
entertheconstantspi(circularratio),e(natural
logarithm base), and TPS (ticks per second).
These constants are case-sensitive: the Expression
Evaluator does not recognize PI, E, or tps.
You can also enter a vector expression or an
Expression Controller function call, but the result
of the expression or function
must be a scalar
value. O therwise, t he Expression Evaluator won’t
evaluate it.
Enter i ng Number s
You can change a numeric value by a relative offset
by highlighting the contents of a numeric field
(not in the Numerical Expression Evaluator) and
typing R or r followed by the offset amount.
Forexample,aRadiusfieldshows70andyou
high light it:
•IfyoutypeR30,30isaddedtotheradiusand
the value changes to 100.
•IfyoutypeR-30,30issubtractedfromthe
radius and the value changes to 40.
Contr ols and Color
The user interface uses color cues to remind you
what state the program is in.
Note: You can customize most of these colors
by using the
Colors panel (page 3–843) of the
Customize User Interface dialog (page 3–836) .
• Red for animation: The Auto Key button,
thetimesliderbackground,andtheborderof
the active viewport turn red when you are in
Animate mo de.
• Yellow for modal function b uttons: When
you turn on a button that puts you in a generic
creat ion or editing mode, the button tur ns
yellow.
• Ye l l ow f o r s p e c i a l a c t i on m o d e s : When you
turnonabuttonthataltersthenormalbehavior
of other f unctions, the button is highlighted
inyellow.Commonexamplesofthisbehavior
include sub-object selection and locking your
current selec tion se t.
Yo u c a n e x i t a f u n c t i o n a l m o d e b y c l i c k i n g a n o t h e r
modal button. Other exit methods supported by
some buttons include right-clicking in a viewport,
or clicking the modal button a second time.
Undoing Actions
You can easily undo changes you make to your
scene and your viewports. There are sep arate
Undo buffers for both the scene object s and each
view por t.
Use the toolbar Undo (page 1–93) and Redo (page
1–94)
buttons or the Edit menu > Undo and Redo
commands to reverse the e ffects of most scene
operations. You can also use CT RL+Z for U ndo
and CTRL+Y for Redo. Most things you do in the
program can be undone.
Use the Views menu >
Undo and Redo (page 1–36)
commands to reverse the effects of most viewport
operations, such as zooming and panning. You
can also use SHI F T+Z for U ndo View Change and
SHIF T+Y for Redo View Change.
You can also undo actions by using the Hold and
Fetch commands on the Edit menu. Choose Edit
menu>Holdtosaveacopyofyoursceneina
temporary file. Then choose Edit menu > Fetch to