9

Camera Tracker: Troubleshooting 685
Relative—
Leaves the pinned object at its current
position in space and moves it s o that its projected
positionrelativetothetrackedfeatureremains
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 t rack an ear for s ome frames,
then a nose for others in a talking animal shot). If
combined w ith grid space, the object is not moved
onto the grid plane, but keeps its heig ht 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
keyframeateachframeinthepinframerange.
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 keyframe reduction afterwards in Track
View .
Ca mera Tra cker : Troubles hooting
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 b e
set too low. Perform a Check Status in the Batch
Trackrolloutandlookatthereportsinthe
Tracking Error Review list. Also try disablin g
the thresholds in the Error Thresholds rollout
one at a time and see if this fixes the problem.
Adjust the problematic threshold as needed.
Yo u c a n a l s o d i s a b l e e r r o r t h r e s h o l d c h e c k i n g
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
needs to be at least big enough to enclose the
movedfeatureandthesurroundingcontrast
area you’ve selected in the feature b ounds box.
3. Make sure the scene objects are associated
correctly with their trackers. You can verify this
by checking the entries in the list at the top of
the Motion Trackers rollout. If there is an object
associated, you will see its name in the list entry,
if not you will see “ <n o object>”. If you open
amoviefileforwhichyouhavepreviouslyset
up track ers in the camera tracker before you
open the associated 3ds Max scene, the objects
won’t be associa ted with their trackers. You
should make sure the correct 3ds Max scene is
open then close and reopen the movie file in
the Camera Tracker so that it can now find the
scene objects.
4. If you have inadvertently swapped the scene
objects for one or more pairs of track ers, the
match-move can’t find a solution.
R epeated M atch-M ove Er r or s
If you get repeated camera match-move er rors,
here’s a list of things to check:
1. Make sure there are at least six features actively
being tracked at the error frame and that at
least two of them are a good distance out the
plane of the others.
2. Check the tracker gizmos in the Movie window
around the frame on which the error occurs to
ensure that no obvious feature tracking errors
exist.
3. If you’ ve disabled any parameters in the Match
section of the Match-Mov e rollout prior to a
match-move, the camera being matched must
be a lready set correctly in the scene for those
parameters. For example, if you disable roll
andFOV,youmustalreadyhavesetthecamera
to the correct FOV and roll orientation, either
directly in 3ds Max, or as a result of a previous
match-move. The matching algorithm uses all