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166 Chapter 11: Space Warps and Particle Systems
particles’speedcanchangeinordertomatchthe
speed of the operator icon. Default=100.0.
If the operator icon changes speed or direct ion
rapidly, increase this va lue to let the par ticles
follow it more closely.
Tip: UsealowerAccelLimitvalueforsmooth
motion, and a higher value when greater accuracy
is needed, such as when the particles should hit
a small target. You can animate this setting (use
Sync By > Event Duration) to specify different
appropriate values, depending on the required
results.
Influence % —Determines the mix of the previous
speed with the speed of the operator icon.
Default=100.0. Range=0.0 to 100.0.
At the default value of 100, the speed is controlled
only by that of the icon. At 0, the icon speed
doesn’t affect p article speed at all. At in-between
values, the mix proportion is determined by the
Influence % value.
Speed Va r iat ion—Enables random variation of the
particles’ speed, so they don’t all move at exactly
thesamerateastheicon.Turnthison,andthen
set the minimum and maximum percentages of
variation. Default=off.
Using Speed Variation can help keep the par ticles
from bunching up as they travel along the
animation path. Note, however, that each
individual particle’s speed doesn’t vary ; it t r avels
at a constant speed.
Min % /Max % —S et the minimum and maximum
percentages, respectively, of particle speed
variation. Default=50.0 (Min %), 100.0 (Max % ).
For example, if you set Min % to 50 and Max % to
200, the particles w i ll vary in speed between half
and two times the speed of the icon.
Use Icon Orientation—Applies animation of the
icon’s orientation to the particles.
By default, Speed By Icon controls particle motion
only by animation of the icon’s position. If you
turn on Use Icon Orienta tion, the software also
applies rotation of the icon to the particle motion.
In essence, this motion is circular, and its extent
dependsonthedistancebetweeneachparticleand
the icon. Default=off.
The best way to understand how this works is by
using it. To tr y out Use Icon Orientation, see this
procedure (page 2–164).
Steer Towar ds Tra jector y —Particles farther away
than the D istance value from the icon are moved
directly toward the icon. Default=off.
Distance—Sets the distance between the particles
and the operator icon beyond which Steer Towards
Trajectory takes effect. Default=10.0.
Parameters Animation group
If you animate the operator settings, the software
can begin applying this animation to all particles
as of t he star t frame of the animation or the first
frame of the current event, or to each particle
based on its age. For instance, if you set Sync By
to Particle Age, and set Speed Variation keys at
frames 0 and 30, then the software will animate
the speed variation for each particle born w h i le
the event is active be tween its birt h and its 30th
frame of existence. A lternatively, if you set Sy nc By
to Absolute Time, the speed variation is animated
from frame 0 to frame 30 of the animation, even if
no particles a re in the event at that t ime. Or, if you
set Sync By to Event Duration, the speed variation
animation is applied to each particle as of the time
that it enters the event. For further information,
see Anim ation Offset Keying group (page 2–158).
Sync B y —Choose the time frame for applying
animated parameters:
•
Absolute T ime—Any keys set for parameters are
applied at the actual frames for which they’re
set.