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Particle Flow Source 135
System M an agement rollout
Use these settings to limit the number of particles
in the system, and to specify the frequency of
updating the system.
Particle Amount group
Upper Limit—The maximum number of particles
the system may have. Default=100000. Range=1
to 10000000.
Tip: You can have more than 10,000,000 particles in
a single system by using multiple particle sources
and wiring them to the same birth event. Note,
however, that Particle Flow is limited to sending a
maximum of 5,000,000 par ticles per event to the
renderer .
Integration Step group
At each integration step, Particle Flow updates the
particle system, applying each active action to
particles in its event. A smaller integration step can
improveaccuracy,atthecostofcalculationtime.
These settings let you apply different integration
steps to the particle animation in the viewports
and at render time.
In most cases, the default Integration Step settings
work fine. One instance in w hich increasing the
integration-step frequency might help is when
fast-moving particles that should collide with a
deflector penetrate it instead.
Viewport—Set the integration step for animation
playback in the viewports. Default=Frame (once
per animation frame). Range=1/8 Frame to
Frame.
Render—Set the integration step at render time.
Default=Half Frame (tw ice per animation frame).
Range=1 Tick to Frame.
There are 4,800 ticks in a second; thus, at the
NTSC video rate of 30 frames per second, there
are 160 ticks per fra me.
Script rollout
This rollout lets you apply a script to the particle
system at each integration step, as well as after
the last integration step of each frame you
view. Use an Every Step Update script to set up
history-dependent properties, and a Final Step
Update script to set up history-independent
properties.
Every Step Update group
The Ev ery Step Update script is evaluated at the
end of each integration step, af ter all actions in
the particle system are evaluated, and all particles
are finally in their respective events. When, for
example, you are setting up Material ID according
to a particle index, it is important to be sure that
particles are not about to jump to another event.
When you set up history-dependent propert ies,
such as speed, it is important to do that at ever y