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Dynamics Utility 663
needs to be at least big enough to enclose the
movedfeatureandthesurroundingcontrast
area you’ve selected in the feature b ounds b ox.
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 “<no object>”. If you open
amoviefileforwhichyouhavepreviouslyset
up trackers in the camera tracker before y ou
open the associated 3ds Max scene, the objects
won’t be associated with their trackers. You
should make sure the correct 3ds Max scene is
open then close and reopen the movie file in
the Camera Tr acker so that it can now find the
scene objects.
4. If you have inadvertently swapped the scene
objects for one or more pairs of trackers, the
match-move can’t find a solution.
Repeated Match-Move Er ror s
If you get repeated camera match-move errors,
here’s a list of things to check:
1. Make sure there are a t least six features actively
being tracked at the error frame and that at
least two of them are a goo d 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-Move rollout prior to a
match-move, the camera being matched must
be already 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 a l l
the “fixed” camera parameters to compute the
ones being estimated and simply won’t work if
they’re fixed at incorrect va lues.
4. You may know that some of the camera
parameters don’t var y during a match
sequence, but you aren’t sure of their values.
One approach to t his situation is to enable all
parameters for an initial match and then apply a
straight-line average filter to them in the Move
Smoothingrollout.Thisautomaticallydisables
them in the Match sect ion and with luck sets
thematagoodestimateofthefixedposition.
Dynamics
Utilities panel > Utilities rollout > More button > Util ities
dialog > Choose Dynamics.
The term dynamics refers to a system of controls
that generate keys to produce animation that
simulates real-world physics. For example, using
standard keyframing techniques to animate a
bouncing ball, you create keys that move the ball
downtothefloor,squashtheball,movetheball
back up, and s o on.
Using a dy nam ics system, you assign physical
properties to the ball and the floor (such as f riction
or amount of bounce), specify which object
wi ll collide against another object (for example,
the ba ll with the floor), place an effect (such as
gravity),inthescene,andthencalculateasolution
over a r ange of f r ames. The result is a number
of keys that produce an animation in which the
balldropsduetothegravityeffect,collideswith
the floor and reacts naturally based on its surface
characteristics.
Note: As of 3ds Max 5, the preferred tool for
dynamics simulation is reactor,availablefrom
the Utilities panel. The rea ctor plug-in lets you