2009

Variation The maximum amount, in degrees per second, by which the spin
rate can vary. The actual variation is calculated once, at random, for each
particle.
Spin Axis group
The Spin Axis setting includes options that let you apply the spin on a random
or specific axis, with optional random variation of the spin axis.
Default=Random 3D.
Random 3D Spins each particle about an arbitrary, random 3D axis.
World Space The spin axis is specified in the world coordinate space.
Use the X/Y/Z settings to specify the spin axis.
Particle Space The spin axis is specified in the local coordinate space of each
particle.
Use the X/Y/Z settings to specify the spin axis.
Speed Space The coordinate space for particle orientation is determined by
the particles' direction upon entering the event.
The X axis is aligned with the particle direction, while the Z axis is
perpendicular to the X axis and is pointed upward with respect to world space
as much as possible.
Use the X/Y/Z settings to specify the orientation for all particles.
Speed Space Follow The coordinate space for particle orientation is determined
by the particles' direction throughout the event. Use this option to allow
particles that change direction during the event to keep the spin axis aligned
with their direction.
The X axis is aligned with the particle direction, while the Z axis is
perpendicular to the X axis and is pointed upward with respect to world space
as much as possible.
Use the X/Y/Z settings to specify the orientation for all particles.
X/Y/Z Use these to set the spin axis. Unavailable for the Random 3D option.
Default=0,0,1. Range=-1.0 to 1.0.
To specify a single axis, set the corresponding parameter to any non-zero
value, and the others to 0. A negative value flips the axis, and reverses the
direction of rotation. The numeric values come into play when you give more
than one axis a non-zero value, in which case their effect is relative to one
another. For example, if you want the spin axis to be oriented halfway between
the positive X and Y axes, you would set X and Y to the same positive amount.
The actual value doesn't matter. Similarly, to set the spin axis to 30 degrees
2864 | Chapter 14 Space Warps and Particle Systems