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Type Choose the type of measurement to test. You can test actual scaling, or
the size before or after scaling. Default=Scale.
For example, if the X-axis size of a particle's bounding box starts out at 10
system units, and you then use the Scale operator to scale it by 150% on the
X axis, the pre-scale size is 10, and the post-scale size is 15. And, of course,
the scale is 150.
NOTE The software measures particle size based on each particle’s bounding-box
dimensions in the particle's local coordinate space. With the low-polygon Shape
options Tetra and Sphere, the result of this measurement might not be the same
as the Shape operator’s Size value.
■ PreScale Size Tests the size before scaling.
■ PostScale Size Tests the size after scaling.
■ Scale Tests the scaling percentage.
Axis Choose the axis to measure. Default=Average.
■ Average Obtains an average measurement by adding the sizes on all
three axes and then dividing by three.
■ Minimum Uses the smallest dimension.
■ Median Uses the middle dimension in order of size. For example, if the
particle dimensions are X=5, Y=6, Z=12, then the number compared to
Test Value would be 6.
■ Maximum Uses the largest dimension.
■ X/Y/Z Uses the specified dimension.
Test True if Particle Value Lets you specify whether the test passes particles
on to the next event if the speed test succeeds or fails. Available for all tests
except True When Accelerates/Decelerates. Default=Is Greater Than Test Value.
By default, Scale Test returns True if the value tested for exceeds the Test Value
quantity, but you can alternatively choose Is Less Than Test Value. For example,
if you set Type to Scale and set Test Value=150 and Variation=0, and choose
Is Less Than Test Value, a particle will move to the next event only when its
scaling factor is less than 150%.
Size group
These settings are available when Type is set to PreScale Size or PostScale Size.
2988 | Chapter 14 Space Warps and Particle Systems