8

Choosing a Transform Center 417
1. User selects sing le o bject.
2. User clicks Use Tra nsform Coordinate Center from Use
Center flyout on Main toolbar.
3. User adds second obj ect to se le ction.
4. Transform center changes to Use S elec tion Center when
selection set contains more than one object.
5. User clicks Use Pivot Point Center while m ultiple objects
still selec ted.
6. User selects sing le o bject.
7. Transform center returns to Use Transform Coordinate
Center (see step 2).
8. User selects multiple objec ts.
9. Transform center returns to Use Pivot Point Center (see
step 5).
Tra nsfor mi ng A bout S napped Points
While the transform center choices are of ten usefu l
at the object level, they are not usually convenient
when transforming sub-object selections. You can
override the active transform center and perform
the current transform about a temporary point
by using snaps . When Snaps is active, and your
selection is locked, the point you snap to wi l l set
the point about which the transform is performed.
Usingthistechnique,youcan:
• Moverelativetotwosnappoints.
• Rotate about a snapped point.
• Scale about a snapped point.
For more details, see
Snap Settings (page 2–38) .
Ani mati on and the Tra nsfor m Center
Because of the nature of keyframing, rotation,
and scale transforms can be key framed properly
only by using an object ’s local pivot point. For
example, while modeling, you can rotate an object
that’s offset from the world origin around the
world center coordinate system. The object sweeps
around the origin in a large arc. However, if you
attempt to animate this, the object rotates about its
localaxisandmovesinastraightlinefromone
end of the arc to t he other.
To avoid this discrepancy, if the Auto Key button is
on and either the Rotate or Scale button is active,
the Use Center flyout is unavailable and set to Use
Pivot Point. When the Auto Key button is off,
all transforms use the center settings previously
described.
You can overr ide this behav ior by tur ning off
Local Center D uring Animate (page 3–870) in the
Animation Preferences settings.
Keep in mind that this affects only the center of
the transform. The orientation of the selected
transformcoordinatesystemisstillineffect.
Animating "Off-Center"
You can animate a rotation or scale about an
off-center point by linking your object as the child