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338 Chapter 12: Animation
In this example, we’ve set it at about 13. The
graph curve is now clipped above the upper
limit and below the lower limit. The resulting
motion is likewise constrained.
8. Scrub the anim ation.
The motion on the X axis is limited at both
extremes; wherever t he object originally moved
beyond the limits, it now behaves as though it’s
hitting a wall.
9. Again compare the two tracks.
The Limit Controller (X Position) t rack clearly
showstheupperandlowerclipping,whilethe
Limited Controller track shows the original
motion.
The original motion still exists as the Limited
Controller track; you can restore it temporarily
by toggling the Limit controller.
10. Highlight the X Position track, and then
right-click and choose Limit Controller >
To g g le L i m it.
Now, when you scrub the animation, the object
movesasbefore.
11. Choose Limit Controller > Toggle Limit again
to restore the limits
You can copy the Limit controller in two
ways: the limits only, or t he limits and motion
combined. First, you’ll copy the limits only.
12. Highlight the Y Position track and note how its
curve differs from that of the X Position track.
13. Highlight the X Position track, and then
right-click and choose Limit Controller > Copy
Limit Only.
14. Highlight the Y Position track, and then
rig ht-click and choose Limit C ontroller > Paste
Limit Only. When the Paste dialog opens, click
OK to confirm the paste as a copy.
Now the Y Position track is also limited, using
the same extents as the X Position track, but
retaining its original underlying motion. To
verify this, compare the Y Position track with
its child Limited Controller track.
Next, you’ll copy the entire limited X Position
track to the Z Position track, including motion
and limits. The Z Position track cur rently is not
animated.
15. Highlight the X Position track, and then
right-click and cho ose Copy.
16. Highlight the Z Position track, and then
right-click and choose Paste.
Compare the X and Z Position tracks and both
their child Limited Controller tracks. Each
correspondingpairofcurvesisidentical.The
motionappearsasthoughtheobjectishitting
theinsideedgeofabox.
Finally, we’ll cover the Smoothing Buffer
settings. By default, sharp corners are created
wherever a cur ve is limited, causing abr upt
changes in motion. You can smooth off these
corners with the Smoothing Buffer parameters,
resulting in more natural-looking motion.
17. Highlight the X Position track, and then
right-click it a nd choose Properties.
This reopens the Float Limit Controller dialog.
18. Use the Upper Limit group > Smoothing Buffer
spinner to increase the Smoothing Buffer value
as far as it can go.
Asyouincreasethevalue,thecornersofthe
upper limit on the graph become smoother.