8

Material Frequency Operator 185
Per S econd—
Sets the number of times per second
that the assigned material ID is incremented.
If this value is the same as the rate at which
particles enter the event, then one ID is assigned
per particle. If it’s lower, then multiple particles
aregiventhesameID,orifit’shigher,thenthe
software increments the assigned ID faster than
1perparticle.
For instance, if particles enter the event at intervals
of 1/60 of a second, and Per Second=30, then
each pair of par ticles will be assigned the same
ID. Or if particles enter the event at intervals of
1/15 of a second, and Per Second=30, then the ID
is incremented (or changed randomly) twice per
part icle.
Per Pa r t icle—Sets the number of particles that must
appear before material ID assignment changes.
For example, If you set Per Particle=3, the material
ID changes every three particles.
If you set Per Particle to a number less than 1.0,
the software then moves through the sub-material
list more rapidly than one (or more) particle per
ID.Thatis,thesoftwaredividesthisvalueinto
1.0, and adds the result to the current material ID
to obtain the next one. For example, with eight
sub-materials, if you set Per Particle=0.33, and
usetheCycleoption,thefollowingseriesofIDs
willresult:1,4,7,2,5,8,3,6,1,...Ingeneral,this
option is useful only with the Cycle option.
Loop—When on, and the last ID has been assi gned,
the software loops back around to the first ID
and continues the cycle. When off, the software
assigns the last cycle ID to a ll subsequent particles.
AvailableonlywiththeCycleassignmentmethod.
Default=on.
For example, say you want the first eight particles
that enter t he event to use different materials, and
all subsequent particles to use a ninth material.
To do so, you would create a nine-sub-material
Multi/Sub-Object material and assign it to the
MaterialStaticoperator.TurnonAssignMaterial
ID, choo se the Cycle assig nm ent method, and set #
Sub-Materials=9. For Rate, use the default settings
of Per Particle and 1.0. Lastly, turn off Loop.
Uniqueness group
The Uniqueness s etting varies the sequence of
assigned IDs with the Random option.
Seed—Specifies a randomization value.
New—Calculates a new seed using a randomization
formula.
Material Frequency Operator
Particle View (page 2–121) >ClickMaterialFrequency
in an event or add a Material Frequency operator to the
particle system and then select it.
The Material Frequency oper ator lets you
assignamaterialtoanevent,andspecifythe
relative frequency with which each sub-material
appears on the particles. Typically, the material
is a Multi/Sub-Object or other compound
material, and you specify the f requency by
setting a percentage for each of up to 10 different
sub-materials (or material ID). The software
assignsIDstoparticlesinarandomsequence,
based on these percentages. You can also use other
materials that use sub-mater ials, such as Double
Sided and Top/Bottom.
See also
Overview of Materials in Par ticle View (page
2–182)
Material Static Operator (page 2–183)
Material D ynamic Operator (page 2–187)