8

Position Object Operator 145
Use the Position Object settings to control the
initial placement of particles on the emitter. You
can set the emitter to emit part icles from its
surface, volume, edges, vertices, or pivot, or from a
sub-object select ion. You can also control particle
emission with a material applied to the object.
Alternatively, you can use the
Position Icon
operator (page 2–143)
to emit particles from the
Particle Flow icon.
Note: Typically, you would use Position Object in a
birth event, so the particles appear initially at the
emitter object(s). If you use it in a non-bir th event,
theparticlesjumptothedesignatedemitter(s)
upon entering the event. This could be useful for a
teleportation effect.
Tip: The default speed oper ator, Speed (page
2–155)
,typicallyusestheParticleFlowiconto
control the direction of the particle flow, so if the
emitter object(s) and the icon aren’t coincident
and alig ned, you might get unexpected results.
For better control over the direction of part icle
movement when using Position O bjec t, use the
Speed By Surface oper ator (page 2–163) instead
and desig nate as Surface Geometry the same
object(s) as w ith Position Object.
Procedure
To use Position Object:
1.
Create a Particle Flow system and one or more
mesh objects to use as emitters. Animate
the emitter objects and set p article system
parameters as necessary.
2. In Particle View, add a Position Object operator
to the bir th event, replacing the Position Icon
operator if one exists. Click the operator to
display its p ar ameters.
3. In the Em itter Objects group, click Add, and
then select an object to serve as the emitter.
Alternatively, click By List and then use the
Select Emitter Objects dialog to designate one
ormoreobjectsasemitters.
4. Use the Location drop-down list to choose
where the particles should appear on the
emitter: surface, vertices, and so forth.
5. Set other options as necessary. For example, if
you want the particles to use the same motion
as the emitter at the time of emission, tur n on
Inherit Emitter Movement. Or if you’re using
an emitter object whose shape is animated, turn
on Animated Shape.