Apple Motion 3 - Manual (Page 717)

Chapter 8 Working with Particles 717
Rectangle: Particles emerge from a rectangle along its edge, or in a tile or random fill
pattern. Using the onscreen controls (with the Adjust Item tool), you can specify the
size and location of the rectangle. Drag the corners to adjust width and height; drag
edges to adjust width or height independently. Depending on the selected
Arrangement, the Rectangle emitter shape displays additional parameters. In the
following image, the Emitter shape Arrangement parameter is set to Outline.
Use the following modifier keys to more precisely manipulate the corners of the
Rectangle onscreen controls (with the Adjust Item tool):
 Option: Adjustments to size are scaled uniformly, with the anchor point remaining
fixed.
 Shift: Adjustments to size are made proportionally.
Circle: Particles emerge from a circle-shaped emitter. Particles can be emitted in an
Outline, Tile Fill, or Random Fill pattern. This emitter shape is good for surrounding an
element in a composition with particles that emerge from its edge. Using the onscreen
controls (with the Adjust Item tool), you can specify the size and location of the circle.
Depending on the selected Arrangement, the Circle emitter shape displays additional
parameters. In the following image, the shape’s Arrangement parameter is set to
Outline.