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Particle Flow FAQ 119
How can I make all particles appear in the first frame
while giving them differe nt ages? (page 2–123)
How can I specify the time frame in which animated
parameters are applied to particles? (page 2–123)
How can I apply bubble motion to particles? (page
2–123)
How can I branch an event to several other events?
(page 2–123)
Does it matter which order I put actions in an event?
(page 2–123)
How can I tell which particles are in a certain event?
(page 2–124)
Whydomyparticleslosetheirmaterialwhenthey
move to another event? (page 2–124)
Can I have an event receive input from multiple
events? (page 2–124)
I changed an operator setting, but it doesn’t seem to
have any effect on the particle system. (page 2–124)
Can an event be isolated in Particle View and not
connected to anything? (page 2–124)
General
How does Particle Flow handle time?
ParametersthatmeasuretimeinParticleFlow,
such as Birth (page 2–143) >EmitStart/Stopand
Age Test (page 2–211) >TestValue,arespecified
in frames. However, Particle Flow is a lways aware
of the current system frame rate (fps), and if
you change this rate, it adjusts all t i me-related
parameters to keep the same timing. For instance,
if you set Test Value to 60 when you’re using the
NTSCframerate(30fps),andthenswitchtoPAL
(25 fps), Particle Flow automatically changes the
valueto50,sotheagethat’stestedforisstilltwo
seconds.
On the other hand, rate parameters, such as Speed,
are measured in units per second, so they don’t
changewhenyougotoadifferentframerate.
When I go to a different frame, the sof tware
sometimes seems to freeze for a while. What’s
going on?
Most of the animation in Particle Flow is history
dependent; that is, to be able to draw the particles
in a particular frame, the program needs to know
what happened in all previous frames. Normally,
when you change a parameter value, the program
needs to recalculate all frames b etween the star t
and the current frames. Or, if you go to a different
frame, Particle Flow must recalculate one or more
animation frames. If you go forward, it must
calculate the f rames b etween the current fr ame
and the one you go to. So, for example, if you just
go to the nex t frame, relatively little calculation is
needed. But if you go backward, even only by one
frame, it must calculate all frames from the start of
the animation to the frame you go to.
If a lot of calculation is needed, there is a delay.
Meanwhile, the software displays a message like
“PF Source 01 U pdate xx% (Press Esc to cancel)”
in the status bar, so you can get an idea of how
the recalculation is progressing. If, when you see
this message, you press the
Esc key, Particle
Flow displays an alert with the me ssage “Click
OK to turn off PF Source 01.” If you click OK, the
recalculation stops, giving you the opportunity
to optimize the animation. For example, you
could reduce the number of p a rticles for testing
purposes. You must turn the source b ack on to
continue. If you click Cancel, the calculation
continues.
Tip: An easy way to speed up recalculation and
rendering of particles is by adjusting the total
number of particles. To do this, select the Particle
Flow source icon, and then go to the Modify panel
> Emission rollout > Quantity Multiplier group .
Here you can increase or decrease by percentage