2009

Add Adds an object to the list. Click Add, and then click an object in the
viewport.
By List Adds multiple objects to the list. Click By List to open the Select Surface
Objects dialog. This works just like
Select From Scene on page 228: Highlight
the objects to use to control speed and direction, and then click the Select
button.
Remove Removes an object from the list. Highlight the object in the list, and
then click Remove.
Animated Shape Turn on to allow particles to follow the surface of an object
whose form is animated by morphing or with modifiers.
Subframe Sampling When on, the operator acquires animation of the Surface
Geometry shape on a tick basis (every 1/4,800th of a second) rather than a
frame basis. This provides greater precision in allowing the particle positions
to follow animation of the Surface Geometry object's form.
Speed by Material Varies particles' existing speed and direction based on
properties of the material applied to each Surface Geometry object. For
example, if an object is assigned a black-and-white checkered diffuse map and
you choose the Grayscale Multiplier option, particles near the white-checked
areas move faster than those from the black-checked areas.
NOTE For material-influenced speed to appear properly in the viewports, two
conditions are required: at least one viewport must be set to a shaded display
mode, and the material or map must have Show Map In Viewport turned on in
the Material Editor.
The options are as follows:
■ Grayscale Multiplier Lets material luminance control speed, with darker
areas producing slower particles and lighter areas producing faster ones.
The software multiplies the luminance of the material near each particle,
converted to a percentage, by the particle's current speed. A luminance of
0 converts to 0%, of 128 converts to 50%, and of 255 converts to 100%.
For example, if the speed of a particle traveling at 50 units per second is
influenced by a pixel whose luminance is 90, the resulting speed is
90/255*50, or about 17.6 units per second.
■ Signed Grayscale Works like Grayscale Multiplier, but the multiplier can
be negative as well, causing reversal of motion. Signed Grayscale uses a
material luminance value of 128 as the midpoint, and assigns it a multiplier
of 0%. Luminance values from 0 to 127 result in multipliers of -100% to
Particle Flow | 2891