2009

When I go to a different frame, the software 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 between the start 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 frames
between the current frame and the one you go to. So, for example, if you just
go to the next 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 Update 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 message “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 particles for testing purposes.
You must turn the source back 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 the total number of particles, separately
for viewport display and rendering.
TIP To speed up animation playback when you're not adjusting parameters, use
the Cache operator (see the following item).
Is there a way to pre-calculate portions of a particle simulation, as in
"baking" the animation?
Yes. Particle Flow's
Cache operator on page 2935 lets you store all or part of a
particle animation in memory, and then play back the animation from memory
rather than having to recalculate particle motion. This makes it much faster
to jump between different parts of the animation. You can even save the
cached animation to disk as part of the scene file.
Particle Flow | 2803