9

Dynamics Utility 689
can repeat this as many times as you like to layer
simulations ad infinitum.
Since U ndo is not supported by Dynamics, you
can also use Hold and Fetch in its place.
1. In Track View, open the Position track for an
object animated by a dy namics simulation.
2. Select the Old Position track, and click Copy
Controller on the Track View toolbar (the
second button from the left).
3. Select the Position track (the parent), and
click Paste Controller (to the right of Co py
Cont roller).
4. Click OK in the Paste dialog.
The two sub-tracks and the Position parent
track are replaced by a single Position track
containing the original keys that were in the
Old Position track.
Repeat the above steps with the Rotation track.
To set up dynamics:
1.
Assignmaterialstotheobjectsincludedinthe
simulation and adjust t he surface characteristics
in the Dynamics Properties rollout of the
Material Editor. (For a bouncing ball, you’d use
this to create a rubber-like surface.)
2. If you’re using a linked hierarchy, set the Move
andRotatelocksintheHierarchy/LinkInfo
panel to limit the motion and rotation of the
linked objects.
3. Create sp ace w arp effects in the scene where
needed. (For a bouncing ball, you’d need a
Gravity space warp.)
4. UsetheDynamicsutilitytocreateanew
simulation. Specify which objects are included
in the simulation, which effects influence which
objects, and which objects should collide with
which. (For the bouncing b all, the b all and the
floor are in the simulation because one collides
with the other. You assign the ball the floor to
collide with each other, and assig n the gravity
effect to the ball.)
5. UsetheDynamicsutilitytospecifytherangeof
frames to w hich keys will be generated, and to
calculate the animation and generate the keys.
(Inthecaseofabouncingball,anumberof
position and rotation keys are generated for the
ball.)
6. Playtheanimationtoseeiftheeffectiswhatyou
were looking for. If one or more objects fly off
into space, or move through objects they should
have bounced off, it’s likely that you need to
increase the Calc Intervals Per Frame value.
To r educe the number o f k ey s gener ated by t he
Dynamics utility :
When you solve a dynamics simulation, Position
and Rotation keys are generated at every frame of
the specified range for every object affected in the
simulation. Not only does this result in an excess
of keys for later editing, but it can increase the size
of the .max file tremendously. The following steps
show how to reduce the number of keys using
Track View.
1. After solving the simulation, check the
animation to make sure it’s what you want, and
then save that version of the scene.
2. Deselect ever y object in the scene.
3. In the Dynamics panel > Objects in Simulation
group, click the Select Objects In Sim button.
All objects included in the simulation are
selected.
4. Open a Track View window, and then set
its filter to show Animated Tracks Only and
Selected Objects Only.
5. Right-click the top object in the Hierarchy list
(Objects), and choose Expand All.
Track View now shows all tracks in the
simulation that have keys.