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140 Chapter 11: Space Warps and Particle Systems
1.
Start or reset the software, and add a new PF
Source object to the scene.
2. Press 6 to open Particle View.
The default particle system contains a Birt h
operator as the first action in the birth event.
3. Try to drag the Birth operator elsewhere in
Event 01.
You c an’t. As you drag over the d ifferent actions
in Event 01, a red line appears at the top of the
event, showing that the Birth operator will b e
placed here, no matter where you release the
mouse button.
4. Try to drag a new Birth operator from the depot
to Event 01.
Asinthepreviousstep,theonlyplaceyoucan
drop the Birth operator is at the top of the event,
replacing the existing Birth operator.
5. From the depot, drag the Birth operator to an
empty area in the event display.
Part icle Flow creates a new birth event, Event
02, containing the Birth operator and a Display
operator .
6. Wire the output of the global e vent, PF Source
01, to the event input of Event 02.
Each birth event must be associated with a
global event to be able to generate p articles.
7. From the depot, add a Send Out test at the end
of both Event 01 and Event 02.
8. Try to wire the test output of Event 02 to the
event input of Event 01.
Part icle Flow doesn’t let you, because this
would result in two Birth operators in series.
9. Try to wire the test output of Event 01 to the
event input of Event 02.
Again, Particle Flow doesn’t let you, because
this would result in two Birth operators in
series.
10. Drag a Speed operator to an empty area of the
event display.
Particle Flow creates a new event, E vent 03.
11. Wire the test output of Event 01 to the event
input of Event 03.
12. Wire the test output of Event 02 to the event
input of Event 03.
There’s no problem wiring the two birth events
to a single, third event. The birth events exist in
the particle stream in parallel, each generating
particles independently and then feeding its
particle stream into a common event, where the
two streams are combined.
If the second birth event had its own global
event, you could, at any point fur ther
downstream, separate the streams back out
according to their orig in using the
Split Source
test (page 2–232)
.Todothis,deletethewire
from PF Source 01 to Event 02, add an
Empty
Flow (page 2–205)
to the system, and then wire
it to Event 02.
Interfa ce
The user interface appears in the parameters panel,
on the right side of the P article View dialog.
Emit S tar t—The frame number at which the
operator begins emitting particles.
Emit S top—The frame number at which the
operator stops emitting particles.