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66 Chapter 11: Space Warps and Particle Systems
decrease Range enough, the bomb no longer
affects all or part of the object (depending on
the placement of the PBomb icon). Test the
three Blast Sy mmetry settings by placing the
bomb in the center of the object and then seeing
the different blast p atterns.
Once y ou get an explosive effect you like, you can
return to the PArray settings, add spin or thickness
to the fragments, and so on.
Inter face
Blast Symmetry group
These options specify the shape, or pattern of the
blast effect.
Spherical—Theblastforceradiatesoutwardfrom
the PBomb icon in al l directions. The icon looks
like a spherical anarchist’s bomb.
Cy lindrical—Theblastforceradiatesoutwardfrom
and normal to the central axis, or core of the
cylindrical icon. The icon looks like a stick of
dynamite with a fuse.
Planar—Theblastforceradiatesbothupanddown,
perpendicular to the plane of the planar icon. The
iconlookslikeaplanewitharrowspointingup
and down along the direction of the blast force.
Chao s —The blast forces vary for each particle or
each f r ame, an effect similar to Brownian motion,
witharateofchangeinthedirectionofforceequal
to the rendering interval rate. Note: This setting is
effective only when the Duration spinner is set to 0.
Explosion Parameters group
Start Time—The frame number at which the
impulse forces are first applied to the particles.
Duration—The number of frames, beyond the
first, over which the forces are applied. Th is
value should typically be a sma ll number, such as
between 0 and 3.
Strength—Thechangeinvelocityalongtheblast
vector, in units per fr ame. Increasing Strength
increases the speed with which the particles are
blown away from the bomb icon.
Unlimited R ange—The effects of the bomb icon
reach all bound particles throughout the scene.
This option ignores the Range setting (which
specifies the distance of the PBomb effect).
Linear—Theimpulseforcesdecaylinearlybetween
the full Streng th setting to a value of 0 at the
specified Range setting.
Ex ponential—The impulse forces decay
exponentially b etween the full Strength setting to
a value of 0 at the specified Range setting.
Range—The maximum distance, in units, over
which the PBomb icon affects the bound particle
system. If the Range is large enough to reach only