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674 Chapter 12: Animation
Object—
Displaysthenameoftheobjectfor
which you’re setting the dynamic properties. All
settingsintheEditObjectdialogaffecttheobject
listed here. To change the objec t you’re affecting,
openthelist,andchoosefromalistofallobjects
assigned to the simulation.
Dynamic Controls group
Use Initial State—When turned on, the simulation
solves for the motion, energy, and momentum
oftheobjectatthesimulation’sstartingframe
(specified in the Start Time spinner in the Time
and Simulation rollout > Timing group.) If Use
Initial State is turned off, the object is assumed
to b e sitting motionless at the star ting frame.
The Dynamics utility overwrites keys. Either the
object’s keys are clocked with the simulation, or
it’s not moving (or both). If you don’t solve for
the initial state, the object’s keys are interpolated
at the instant the simulation starts and all
subsequent motion comes from the interaction of
the simulation itself.
This Object is Unyielding—Lets you use
key f rame-animated objects in dynamics
simulations. Objects with this option tur ned on
areimmovablerelativetootherobjectsthatcollide
w ith them, but can be animated (keyf r amed).
You can animate objects with this option turned
on by themselves or as part of a keyframed
hierarchy. For collisions, objects with Use Initial
State turned on cannot move objects with This
Object is Unyielding turned on.
Move Pivot to Centroid—When this button is on
(green) and you exit the Edit Object dialog by
clicking OK, the object’s pivot point is moved to its
center of mass. Hav ing the pivot alig ned with the
center of mass speeds up t he dynamics calculation
and makes manual keyframing of the objects
appear more natural. However, if the pivot point
is already positioned as part of a linked hierarchy,
turning on Move Pivot to Centroid will alter the
positioning of your hierarchical linkage.
Load/Save Parameters S ets group
Saves the current Edit Object parameter settings,
or loads previously saved parameter settings. You
can use these controls to save the settings for one
object, and then apply them to another object.
Set Name—Accepts a new name for a parameter
set. Click Save to s ave the pa rameter set with this
name.
Available Parameters Sets—Lists previously saved
parameter sets.
Loa d—Loads the selected p arameter set.
Save—Saves the named parameter set. The saved
parameter sets appear in the list.
Delete—Deletes the selected parameter set.
Assign Effec ts/Collisions group
Let you specify which effects in the scene will affect
the cur rent object, or which objects in the scene
can collide with the current object.
As s i gn Ob j e ct E f f e cts —Displays a subdialog that
lets you specify w h ich effects in the scene will affect
the current object . The dialog consists of two list
w indows. All effects (typically space warps) in the
scene are listed in the window on the left. Select
effects in the list, and then click the > button to
transfer the highlighted effects to the window at
right.
The Assign Object Effects dialog functions
similarly to the
Edit Object List dialog (page
2–677)
.
Assign Object Collisions—Displays a subdialog that
lets you choose which objects in t he scene are
considered for collision w ith the current object.
This dialog works the same as the Assign Object
Effects dialog, except that it lists only objects in the