5.1.1

Chapter 14 Particles 538
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Life Randomness: A slider that denes an amount of variance in the life of generated particles.
A value of 0 results in no variance—all particles from the selected cell emerge with the same
lifetime. A value greater than 0 introduces a variance dened by the Life parameter, plus or
minus a random value falling within the Life Randomness setting.
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Speed: A slider that denes initial speed. This parameter determines how quickly each particle
ies away from the emitter. This, in conjunction with the Life and Birth Rate parameters,
determines how many particles appear in the Canvas at a given frame. It is equivalent to one
of the functions of the graphical emission control in the HUD.
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Speed Randomness: A slider that denes an amount of variance in the speed of generated
particles. A value of 0 results in no variance—all particles from the selected cell emerge with
the same speed. A value greater than 0 introduces a variance dened by the Speed parameter,
plus or minus a predetermined random value falling within the Speed Randomness setting.
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Align Angle: When this checkbox is selected, particles rotate to match the shape on which
they are positioned. This parameter is available in all cases but the following: when the
Shape setting (in the Emitter Inspector) is Rectangle, Circle, Image, Box, and Sphere and the
Arrangement setting is with Tile Fill or Random Fill; or when the Shape setting is Point.
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Angle: A dial that denes the angle of rotation, in degrees, at which new particles are created.
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Angle Randomness: A dial that denes an amount of variance in the angle of
generated particles.
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Spin: A dial that animates particles in a system by initially spinning each particle around its
center. Adjustments to this control are in degrees per second.
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Spin Randomness: A dial that denes an amount of variance in the spin of generated particles.
A value of 0 results in no variance—all particles from the selected cell spin at the same rate.
A value greater than 0 introduces a variance dened by the Spin parameter, plus or minus a
random value falling within the Spin Randomness setting.
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Additive Blend: By default, particles are composited together using the Normal blend mode.
Select this checkbox to composite all overlapping generated particles together using the
Additive blending mode. This blending occurs in addition to whichever compositing method
is already in use. The result is that the brightness of overlapping objects is intensied. This
eect applies to the particle system itself—the blend mode of the emitter determines how the
result of the emitter is blended into the scene.
Additive Blend off
Additive Blend on
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