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158 Chapter 11: Space Warps and Particle Systems
If you choos e Inherit Prev ious but no direction
was previously specified, the speed and direction
are undefined; the part icles don’t move.
Reverse—When on, the direction is reversed.
Default=off.
Using Reverse is the equivalent of multiplying the
Speedvalueby-1. Thisoptionisunavailableif
Random 3D or Random Horizontal is chosen.
Divergence—When on, spreads out the particle
stream. Use the numeric setting to define the
extent of the divergence, in degrees. Range=0 to
180. Default=0. The value can b e animated.
This option is unavailable if Random 3D is chosen.
Tip: For a fountain-like spray, set Position >
Location to Pivot, set Direction to Along Icon
Arrow, set Divergence to the desired angle, and
rotate the icon so its arrow points upward.
Uniqueness group
The Uniqueness sett ing enables randomization of
speed variation, and randomization of direction
with the Ra ndom 3D and Random Horizontal
options.
Seed—Specifies a randomization value.
New—Calculates a new seed using a r andomization
formula.
Speed By Icon Operator
Particle View (page 2–121) > Click Speed By Icon in an
event or add a Speed By Icon operator to the particle
system and then select it.
Click a Speed B y Icon operator icon in the viewport >
Modify panel
Create panel > Helpers > Particle Flow > SpeedByIcon
The Speed By Icon operator lets you use a special,
non-rendering icon to control par t icle speed and
direction.
Speed By Icon operator icon
When you add a Speed By Icon operator to the
particle system in
Particle View (page 2–121) ,the
Speed By Icon
operator icon icon appears in the
scene at the world origin (0,0,0). When animated,
theoperatoricon’smotionisimpartedtothe
part icles. If you delete the icon, the software also
deletes the operator.
Note: If you add Speed By Icon from the Create
panel, Particle Flow creates a separate event for the
operator in the par t icle diagram.
Wa rn in g: If you delete a Speed By Icon operator icon
in the viewport, you also delete the corresponding
operatorintheParticleFlowsystem.
See also
Speed Operator (page 2–155)
Speed By Surface Operator (page 2–163)
Keep Apart Operator (page 2–168)
Procedures
To u se the Sp eed B y I con oper ator :
1.
Add a Speed By Icon operator to an event. B e
sure to add it
after any exist ing Speed operators
in the event. Alternatively, delete or turn off any
existing Speed operators.
The Speed By Icon operator icon appears at the
world origin (0,0,0).
2. Animate the icon as you would any object. You
can do this manually, or w ith a controller such