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Start Point: This parameter, which becomes available when Shape is set to Line or Wave,
consists of two value sliders that define, in X and Y coordinates, the first point of the line
used as the emitter shape. Click the disclosure triangle to modify the Z position of the
start point. You can adjust these values in the Canvas using the onscreen controls (with
the Adjust Item tool).
End Point: This parameter, which becomes available when Shape is set to Line or Wave,
consists of two value sliders that define, in X and Y coordinates, the second point of the
line used as the emitter shape. Click the disclosure triangle to modify the Z position of
the start point. You can adjust these values in the Canvas using the onscreen controls
(with the Adjust Item tool).
Emit At Points: This checkbox is available when any of the following is chosen in the
Shape pop-up menu: Line, Rectangle (with Arrangement set to Outline or Random), or
Circle (with Arrangement set to Outline or Random), Burst, Spiral, Wave, Geometry, Box
(with Arrangement set to Outline), or Sphere (with Arrangement set to Outline). When
the Emit At Points checkbox is selected, particles emerge from a limited number of points
(as defined in the Points parameter). When the checkbox is deselected, particles may
emerge from anywhere on the line or edge. When the Adjust Item tool is selected, the
points become visible in the Canvas. When Emit At Points is selected, two additional
parameters become available: Points and Offset.
Points/Points Per Arm: This slider becomes available when any of the following is chosen
in the Shape pop-up menu: Line, Rectangle, Image, or Circle (with Arrangement set to
Outline or Random Fill), Burst, Spiral, Wave, or Geometry; in addition, the Emit At Points
checkbox must also be selected. Defines the number of points where 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.
Using a large number of points slows your computer’s processing performance.
Radius: This slider becomes available when one of the following is chosen in the Shape
pop-up menu: Circle, Burst, Spiral, or Sphere. Defines the size of the shape from which
particles are emitted.
Twists: This slider, available when Spiral is chosen in the Shape pop-up menu, defines
the number of turns in the spiral. The default value is 0.25.
702 Chapter 14 Working with Particles