User Manual

Table Of Contents
Temporal Distribution
In general, an effect is processed per frame, based on the comp frame rate. However,
processing some particles only at the exact frame boundaries can cause pulsing. To makethe
behavior subtly more realistic, the particles can be birthed in subframe increments.
The default, At The Same Time setting renders on frame boundaries, where as the other two
settings take advantage of sub frame rendering. Randomly Distributed randomizes birth times
+/- around the frame number, eg birth 10 particles at random sub times 24.1 24.85, 24.21, 24.37
etc. one particle at a time. Evenly Distributed births particles at regular sub times, eg 10
particles, birth 1 at at time at 24.0, 24.1, 24.2, 24.3, 24.4, 24.5 ... 24.8, 24.9.
These settings are influenced by the Sub Frame Accuracy setting in the pRender node. The
Sub Frame Accuracy slider controls how many in-between frames are calculated between each
frame. The higher the value the more accurate the particle calculation but the longer the
render times.
Velocity
The controls in the Velocity section determine the speed and direction of the particle cells as
the are generated from the emitter region.
Velocity and Velocity Variance
These determine the initial speed or velocity of new particles. By default, the particle has no
velocity and will not move from its point of origin unless acted upon by outside forces. A
velocity setting of 10.0 would cause the particle to cross the entire width of the image in one
step so a velocity of 1.0 would cause the particle to cross the width of the image over 10 frames.
Velocity Variance modifies the velocity of each particle at birth, in the same manner described
in Lifespan Variance and Number Variance above.
Inherit
Inherit Velocity passes the emitter region’s velocity on to the particles. This slider has a wide
range that includes negative and positive values. A negative value causes the particles to move
in the opposite direction, a value of 1 will cause the particles to move with a velocity that
matches the emitter region’s velocity, and a value of 2 causes the particles to move ahead of
the emitter region.
Angle and Angle Variance
This determines the angle at which particles with velocity applied will be heading at their birth.
Angle Z and Angle Z Variance
This is as above, except this control determines the angle of the particles along the Z space
axis (toward or away from the camera).
Rotation
Rotation controls are used to set the orientation of particle cells and animating that orientation
over time .
Rotation Mode
This menu control provides two options to help determine the orientation of the particles
emitted. When the particles are spherical, the effect of this control will be unnoticeable.
Absolute Rotation: The particles will be oriented as specified by the Rotation controls,
regardless of velocity and heading.
Rotation Relative To Motion: The particles will be oriented in the same direction as
the particle is moving. The Rotation controls can now be used to rotate the particle‘s
orientation away from its heading.
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