8

662 Chapter 12: Animation
Pin Range group
Movie Start—Sets the movie frame from which to
start us ing tr acked feature posit ions.
Animation Star t—Sets the frame in the 3ds Max
animationatwhichtostartkeyframingthemove
of the pinned object.
Fr am e Cou n t —Sets the number of frames to
animate. There must be enough tracked positions
in the selected tracker to cover this number of
frames.
Reset Ranges—Reloads the maximum frame
number and count ranges into the above spinners
fromthecurrentmovieand3dsMaxscene
settings.
Pin Space group
Lets you select the plane of motion i n which the
keyframed pinning will occur.
Screen—Moves a nd animates the pinned object
in the plane of the screen at its cu rrent depth in
thescene.Thisisequivalenttodragginganobject
around in the Screen reference coordinate system
in 3ds Max.
Grid—Moves and animates the pinned object in
the plane of the currently active g rid. This lets you
set up an arbitrary plane of motion for the pinning
by constructing a grid helper object in the desired
place and making it the active grid. If you don’t
have a grid helper set up and active, the pinning
will occur on the 3ds Max Home Grid.
Pin Mode Group
Lets you choose between two different pinning
modes: absolute and relative.
Absolute—Places and moves the pinned object
exactly over the tracked feature. If combined with
gr id space, the object is also placed a nd moved
directly on the active grid plane.
Relative—Leaves the pinned object at its current
position in space and moves it s o that its projected
position relative to the tracked feature remains
thesamethroughoutthepinningframerange.
This makes it possible to animate an object that
you don’t want placed exactly over a feature, or
to animate an object using several features in
successive frame ranges. (For example, a computer
generated jaw can track an ear for some frames,
then a nose for others in a talking animal shot). If
combined with gr id space, the object is
not moved
onto the g rid plane, but keeps its height above the
grid and is moved parallel to it.
Pin—Performs the actual pinning, moves the
object to follow the selected feature and places a
keyfr ame at each frame in the pin frame range.
As with the other keyframing operations in the
tracker, you can undo a pin using the 3ds Max
Undo function. You might also find it useful to
perform key frame reduction afterwards in Tr ack
View.
Camer a Tr a cker : Trou bleshooti ng
Feature Track ing Halts Immediately
If the feature tracker attempts to match the first
couple of frames but halts immediately, check
these steps:
1. One of the enabled error thresholds might be
set too low. Perform a Check Status in the Batch
Track rollout and look at the reports in the
Tracking Error Review list. Also try disabling
the thresholds in the Error Thresholds rollout
one at a time and see if this fixes the problem.
Adjust the problematic threshold as needed.
You can also disable error threshold checking
altogether by turning off the Resample On
Error check box in each of the tr ackers.
2. Make sure the search bounds box for each
tracker is big enough to accommodate the
frame-to-frame motion of the feature. Th is