9

Find Target Test 223
Follow Target A nimation—
Turn on to a llow
particles to follow a moving target; that is, a target
whose loc at ion is animated. This requires more
computation, because the destination must be
updated at every integration step.
Point—Lets you specify where on its target a
particle should land.
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Random—E ach part icle targets a random point
on the target.
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Clo ses t Surface—Each particle targets the
nearest point of the target’s surface.
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By Script Vector—The target point or points are
definedusingaScriptoperatorthatdefines
values in the particleVector channel. The Script
operator can be anywhere upstream of the Find
Target t est.
Note: When using By Script Vector to target
absolute positions, such as vertex lo cations,
be sure to set Target to Icon. If you set it to
Mesh, the positions specified by the script will
be relative to the position of the mesh object.
This latter option is useful for placing scripted
targets on the surface of a movi ng object.
Object—With mult iple mesh targets, lets you
specifyhowthesoftwareshouldchooseamong
them. Available only when targeting more than
one object.
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Random—For each par ticle, the software
choosesatargetobjectatrandom.
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Clo ses t Pivot —For each p article, the software
chooses as its target the object whose pivot is
nearest to the particle.
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Clo ses t S u rf ace—For each particle, the software
chooses as its target the object whose surface is
nearest to the particle.
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Lea st D ev ia t i on—For each par ticle, the software
chooses as its target the object that requires
the least change in its current direction (or
resteering) to reach.
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By Script Integer—For each particle, the
choice of a targeted object is defined by a
script operator that sets an index. This index
corresponds to a target-object entry position
in the target list. See Script Operator Example
(page 2–224).
Lock On Tar get Object—When on, the software
calculates each particle’s target object once: when
the particle enters the event. Thereafter, the
particle is “locked on” to its target object. When
off, the software can continually recalculate the
target object for each particle. Available only when
multiple target objects are designated.
For example, if you set particles to target the closest
surface, due to the target animation and particle
movement, the definition of the closest surface is
constantly changing. Thus the particle may change
thetargetobjectduetothecircumstances.
Note: Each ti me Find Target sets a target object,
it “locks on” to a specific point on that objec t.
This point can change only if the target object
changes. Thus, with a sing le target object, the
target point always remains constant relative to
the target object.Thatis,ifthetargetobjectorits
surface is animated, and Follow Target Animation
orAnimatedShapeison,theabsolutecoordinates
of the target point may change.
Note: When L o ck On Target Object is off, more
calculation is required b ecause the system might
have to recalculate each particle’s optimal target
point in each frame.
Dock ing Direction group
Docki ng ty pe—Lets you specify from which
direction particles should approach targets.
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None Specified—No docking constraints.
Part icles reach their targets in the most efficient
way, based on their assigned parameters and
their current attributes.