8

412 Chapter 12: Animation
Selection buttons on the toolbar. (See Animation
Constraints (page 2–375)
.)
An example of using a link constraint is to pass
a ball from one hand to another . Assume that at
frame 0 the ball is in the first hand. The hands
are animated to meet at frame 50 and then spread
apart until frame 100.
To animate the links for the ball:
1.
OntheMotionpanel,assignaLinkconstraint
as the ball’s Transform controller. You can
also put a Link constraint on the ball from the
Animation menu by choosing Constraints >
Link Constraint.
2. Move the time slider to frame 0, then on the
MotionpanelclickAddLink,andclickthe
hand holding the ball. The ball will now move
along with the hand, as if it were linked to it.
3. Movethetimeslidertoframe50,whereyou
want the second hand to pick up the b all, click
Add Link, then click the second hand. From
thisframeon,it’sasiftheballwerelinkedto
the second hand.
When you play back the animation, the ba l l travels
withthefirsthanduntilframe50,whereyou
added the second link, then the ball is passed to
thesecondhandfortherestoftheanimation.
Robot arms pass a ball from one hand to the other.
Adding and Delet ing Links
You add and delete links on the Motion panel.
Expand the Link Parameters rollout and click Add
Link or Delete Link.
• Click Add Link then click the object that you
want to link to as a parent. The frame at which
youaddthelinkistheframeatwhichcontrolis
passed. You can change the link frame with the
Start Time parameter.
• Clickthenameofaparentobjectinthelist,and
then click Delete Link to remove the link.
Properties of the Link constraint include:
• The Link constraint respects the link
inheritance settings applied to the child object.
• The object using a Link constraint is not a true
child object. It does not appear in the subtree of
any linked parent objects.
• Objects with Link constraint do not participate
in IK solutions.