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136 Chapter 11: Space Warps and Particle Systems
integration step, because otherwise the final
position would be quite different.
Enable Script—Turn on to cause a script in memory
to be executed at each integration step. You can
modify this script by clicking the Edit button,
or load and use a script file with the remaining
controls in this group.
The default script modifies part icle speed and
direction, causing particles to follow a wavy path.
Edit—Clickthisbuttontoopenatext-editor
w i ndow with the current script.
When Use Script File is off, this is the default Every
Step Update script (
3dsmax\scripts\particleflow\
example-everystepupdate.ms
). When Use Script
Fileison,thisistheloadedscript,ifyou’veloaded
one. If you haven ’t, clicking Edit displays the Open
dialog.
Use Script File—When on, you can load a script file
by clicking the button below.
[button]—Click this button to display an Open
dialog that lets you specif y a script file to load f rom
disk. After you load a scr ipt, the name of script file
appears on the button.
Final Step Update group
The Final Step Update script is executed af ter the
last integration step has been completed for each
fr ame that you v iew (or render). For example, if
youplaytheanimationintheviewportwithReal
Time turned off, Particle Flow runs this script
at each frame, immediately before the par ticle
system is rendered to the viewport. However, if
you simply jump to a different fr ame, the script is
runonceonly,soifthescriptassumesacertain
history, you might get unexpected results.
For this reason, it’s best to use the Final Step
Update script to modify history-independent
properties. For example, if no operators in the
system depend on the material indices, you could
use it to mo dify the material index. In this case
there’s no need to set those indices in every
intermediate integration step. Also, you can set
up a position channel in the Final Step Update
script if you know the analytical expression for the
position.
Enable Script—Turn on to cause a script in memory
to be executed after the final integration step. You
can modify this script by clicking the Edit button,
or load and use a script file with the remaining
controls in this group.
The defau lt script modifies particle speed and
direction, causing part icles to follow a bulb-shaped
path.
Edit—Click this button to open a text-editor
window with the current script.
When Use Script File is off, this is the default Final
Step Update script (
3dsmax\scripts\particleflow\
example-finalstepupdate.ms
). When Use Script
Fileison,thisistheloadedscript,ifyou’veloaded
one. If you haven’t, clicking Ed it displays the Open
dialog.
Use Script File—When on, you can load a script file
by clicking the button below.
[button]—Click this button to display an Open
dialog that lets you specify a script file to load from
disk. After you lo ad a script, t he name of script file
appears on the button.
Pa rt icle Flow Keybo ar d Sh ort cut s
TouseParticleFlowkeyboardshortcuts,the
Keyboard Shor tcut Override Toggle on the main
toolbar must be turned on.
To view and customize these shortcuts, open
the Customize U ser Interface dialog from the
Customize menu, and then, from the Group
drop-down menu, choose Particle Flow.