9

Speed By Icon Operator 165
1.
Reset the software, and then add a Particle
Flow system in the Perspective v iewport. Set its
position to the world origin: (0,0,0).
2. Open Particle View and click the Birth operator.
Set Emit Stop=0.
This causes all particles to appear at frame 0.
3. Click the Speed operator and press the Delete
key to delete it.
4. Drag a Speed By Icon operator from the Depot
to the end of Event 01.
The Speed By Icon operator icon appears at the
world origin.
5. Select the Speed By Icon operator
icon, a nd then right-click the icon and choose
Rotate from the menu. Go to frame 20, turn
on Auto Key, and rotate the icon 180 degrees
about the X axis.
6. Turn off Auto Ke y.
7. Dragthetimeslider.
The particles aren’t affected by the icon
animation.
Because the Speed By Icon operator icon is
selected, the operator’s parameters appear on
the Modify panel.
8. OntheModifypanel,turnonUseIcon
Orientation. Drag the time slider again.
This time, the particles move in unison with the
icon rotation, as if they were glued to an infinite
plane coincident with the icon.
9. Gotoframe10,selecttheParticleFlowsource
icon (not the Speed By Icon operator icon), and
then right-click the icon and choose Move from
the menu. Move the icon straight up, on the Z
axis, about 100 units.
As you drag upward, the par ticles move away
from the icon.
10. Drag the t ime slider again. This time the
particles mo ve in an arc around the icon.
11. Try moving and rotat ing the two icons, play ing
the animation each time you make a change.
AlsosetEmitStopbackto30.
As you can see, t he possibilities with just this
simple setup are myr iad. In combination with
the many other variables and options in Particle
Flow, t hey’re endless.
Interfa ce
The user interface appears in the parameters panel,
ontherightsideoftheParticleViewdialog.When
the icon is selected, the parameters also appear on
the Modify panel.
Accel(er ation) Limit—The maximum amount, in
system units per second per second, by which the