How
to Toss Objects: Method One
The Add Transition technique taught above could also be used to
hand an object from one arm to another directly. If the arms are
not near each other, and you want to toss the object, then you would
use the Add Transition with a frame offset.
To learn about
tossing objects, you should use the following lesson file. This
file contains two arms that have already been animated to pantomime
a tossing motion. A ball has already been parented to the first
arm's chain_goal. With Dynamic parenting, you will
toss the ball to the other hand.
1.
Select the Child Object
Press tab
> Character > Dynamic Parent. Click on
the ball to select it as the child object then RMB-click
to accept. At this point nothing has happened. The next step is
to add a transition.

2.
Toss the Object
Scrub forward
in the time slider until the point where the first hand appears
to release the ball (about frame 68). Click the Add
Transition button found in the Operation control
bar. Next, set the Frame Offset
to about 32
and press Enter.
(Make sure your cursor is still over the offset field when you press
enter or else the value will not be set). Click on the chain_goal
of the arm and RMB
to accept.
Now scrub in
the timeline back and forth. The ball is tossed directly to the
other hand. In the Network pane, you can see that a blend node is
added and is used to parent the ball to the two chain_goals and
a visible transition_null object which controls
the ball as it travels from one hand to the other. Later you can
key this object to refine the motion during the toss.

3.
Edit the Second Arm
Press tab
> Generic > Transform, select the second
arm's chain_goal and RMB
to accept. Scrub forward to the frame where the ball is caught (frame
100). Make sure that the ball's transformation channels are highlighted
green in the Parameter pane. Now move the hand up to a new position.
Because you are on a frame that is keyed, the new position is used
to edit their values.
Playback the
animation. Now the ball moves to the same position it used to then
snaps up to the hand once it is parented. You can use the Dynamic
Parenting tool to bring the ball back in line with the new position
of the hand.

4.
Snap the Transitions
Press tab
> Character > Dynamic Parent. Click on
the ball to select it as the child object then RMB-click
to accept. Click on the Snap Transitions button.
Playback the
animation. Now the ball is moving to the new position of the hand.
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