9

Material Static Operator 187
to color the p articles. By animating the mapping
coordinates, you can cause the particles to change
color over time. This is particularly effective with
a gradient material.
The Bitmap map (page 2–1631),usedin
conjunction with Material Dynamic, lets you
assign different frames from an image sequence to
particles based on the particle age, among other
effects.
Followingaresomeitemstokeepinmindwhen
using materials with Particle Flow:
•Amaterialisastaticpropertyofanevent.It
does not travel along with the p articles f rom
oneeventtothenext.Aparticle’smaterialID
does,butitsmaterialdoesnot. Ifyouwant
particlesalwaystousethesamematerial,define
the material in the global event (page 3–949)
withaMaterialoperatororaShape Instance
operator (page 2–178). Otherwise, you need to
define it in each local event.
• The primitive particle shapes available with
the Shape operator (page 2–176) do not have
mapping coordinates. The Mapping oper a tor
(page 2–195) applies the same mapping
coordinates to each particle’s entire surface, so
it’s not suitable in this situation. If you want to
apply image-based materials to particles, use
Shape Instance (page 2–178) instead.
• If you use a Material operator with Shape
Instance (page 2–178),besuretoapplymapping
coordinates to the reference object(s) (page
3–1002). You can do this by making sure the
object’s Generate Mapping Coords option is on
(if available), or apply i ng a UVW Map modifier
(page 1–922) or Unwrap UVW modifier
(page 1–878).Ifyoudon’tapplymapping
coordinates, the system generates a Missing
Map Coordinates warning when you render
the scene.
• If you use an object with a material already
applied as a reference object (page 3–1002) for
instanced particles, you don’t need a Material
operatorinthesameevent. However,the
material appears only in the event containing
the Shape Instance operator (page 2–178);it
does not persist from event to event.
•IfyouusetheCache operator (page 2–197) with
Update set to Always, toggling the Material
Editor > Show Map In Viewport switch causes
P article Flow to recalculate the cache.
• You can drag a material from the Material
Editor to a Particle Flow source icon, but the
materialwillnothaveanyeffectonthesystem.
YoumustuseaMaterialoperatororShape
Instance to apply materials to particles in
Particle Flow.
• Once you’ve assigned a material to a Material
operator, the material shows up in the Material
Editor as “hot”; that is, triangles appear in the
corners of its sample slot. However, b ecause of
the nature of the Particle Flow data structure,
the Material Editor functions Select By Material
and Get Material > Browse From Selected do
not work correctly with Par ticle Flow systems.
You can, however, use Get Material > Browse
From Scene.
Mater ial Static Operator
Particle View (page 2–125) > Click Material Static in an
event or add a Material Static operator to the particle
system and then select it.
The Material Static operator lets you give part icles
material IDs that remain constan t throughout the
event. It a lso lets you assign a material to e ach
part icle based on its material ID. The operator
can assign the same material ID to all particles, or
different IDs to successive particles on a cyclical
or random basis. The most common usage of
this latter capability is with a Multi/Sub-Object
material, for applying a different material to each
part icle.