Apple Motion 3 - Manual (Page 244)

244 Chapter 2 Creating and Managing Projects
Fixing the Size of a Group
By default, the size of a group is determined by the layers within that group. Because
animated objects often grow in size, the active height and width of a group (its
resolution) can become quite large. You can constrain the resolution of a group to a
specific width and height in the Group tab of the Inspector.
The project shown in the following image contains a particle system. Notice that the
animated particles, although not visible once they move off the Canvas, make the
group containing them very large.
You can crop the size of a group that contains growing objects using the Fixed
Resolution checkbox in the Group tab of the Inspector.
If your project contains animated objects that move or expand beyond the edges of
the Canvas and you don’t activate the Fixed Resolution checkbox, your computer
processing time may increase.
Note: The Group tab of the Inspector (which contains the Fixed Resolution parameter)
is only accessible when a group is selected in the project.
Default size of a layer containing particles
Particles bounding box
Layer with Fixed Resolution turned on