Apple Motion 3 - Manual (Page 721)

Chapter 8 Working with Particles 721
Size (Rectangle, Box): Defines the size of the rectangle or cube from which particles
are emitted. This parameter is available whether the Arrangement is set to Outline, Tile
Fill, or Random Fill. When Rectangle is the selected shape, the Width and Height
parameters are available. When Box is selected, an additional Depth parameter is
available.
Note: The Height is measured in project pixels; however, the Width is measured in
square pixels. This is done so that a shape that is numerically square will look square
when Correct for Aspect Ratio is turned on (checkmarked) in the View pop-up menu in
the top-right corner of the Canvas.
Emit At Points (Line, Rectangle [Outline, Random] or Circle [Outline, Random], Burst,
Spiral, Wave, Geometry, Box [Outline], Sphere [Outline]): When turned on, particles
emerge from a limited number of points (as defined in the Points parameter). When
turned off, particles may emerge from anywhere on the line or edge. When the Adjust
Item tool is selected, the points are visible in the Canvas. When Emit At Points is turned
on, two additional parameters appear:
 Offset (Line, Rectangle [Outline], Circle [Outline], Burst, Spiral, Wave, Geometry,
Image): Offsets either the emitter itself or the particles generated on the shape. For
example, when the emitter Shape is a Line, changing the Offset value moves the
emitter’s position in the Canvas. When the emitter Shape is a Rectangle and Pattern
is set to Outline, changing the Offset value moves the particles along the edge of the
shape.
 Points/Points Per Arm (Line, Rectangle, Image, or Circle [Outline or Random Fill],
Burst, Spiral, Wave, Geometry): Defines the number of points from which particles
are emitted. For Rectangle or Circle shapes, the particles are emitted from evenly
distributed points along the edge of the shape when Outline is chosen from the
Pattern pop-up menu. When the Adjust Item tool is selected, the points are visible in
the Canvas.
Keep in mind that using a large number of points slows your computer’s processing
time.
Radius (Circle, Burst, Spiral, Sphere): Defines the size of the shape from which particles
are emitted.
Columns (Rectangle, Circle, Image, Box, Sphere): When Tile Fill is selected, this
parameter specifies the number of horizontal emitter points on a grid over the selected
emitter shape. In the case of an irregular shape (nonrectangular), grid points that fall
outside of the shape are ignored.
Rows (Rectangle, Circle, Image, Box, Sphere): When Tile Fill is selected, this parameter
specifies the number of vertical emitter points on a grid over the selected emitter
shape. In the case of an irregular shape (nonrectangular), grid points that fall outside of
the shape are ignored.