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range. At the same time, by default, the animation plays in the viewports. To
prevent this, and speed calculation, turn off Update Viewports.
If the cache runs out of memory during a manual update, Particle Flow halts
the update operation and displays an alert. Click OK to continue, and then,
if possible, increase the Limit value before updating the cache again.
Clear Deletes any cached data.
After you clear the cache buffer, if you go to a different frame or change any
action parameters, the software automatically caches particle motion even if
Update is set to Manually.
Range Sets the frame range within which the Cache operator recalculates data
when you click Update. Default=Active Segment.
■ Complete The software clears the cache for entire animation. Choosing
Complete makes the Update button unavailable; this option is for clearing
the cache only.
To update the entire animation, set the active segment or the custom range
to encompass all frames, and then use the corresponding choice and click
Update.
■ Active Segment The software updates the cache only for frames in the
active segment, as defined by the Start Time and End Time settings on the
Time Configuration dialog. This is the frame range shown on the track
bar. You can also change the active segment by holding down Alt+Ctrl and
dragging the track bar with the left, middle, or right mouse button.
■ Custom The software updates the cache only for only frames in the
custom range, as defined by the Start Time and End Time settings (see
following).
Start/End Time The first and last frames of the range that's updated when
Range=Custom (see above). Defaults=0, 30.
Update Viewports When on, the animation plays in the viewports during
manual updating of the cache. Turn this off to disable playing the animation
in the viewports during manual caching; this can speed up the caching process,
especially with large or complex particle systems. Default=on.
Memory Used (K) group
The Cache operator stores data in system memory; you can specify an upper
limit for the amount of memory it uses. If the Limit setting and the amount
of cached data exceeds the available free memory, the computer system might
2942 | Chapter 14 Space Warps and Particle Systems