5.5

329Motion User Guide
When using the Link behavior to control an object’s position parameter, the linked
coordinates are based on the center point of the current group. So when an object is linked
to another object in the same group, it shares an identical position. However, if the source
object is in a different group, the coordinates might appear offset in space.
If your goal is to match an identical position across groups with different center points, you
can create an invisible reference object in the group containing the source, link it to the
source object, then use the Match Move behavior to copy the reference object’s position
to that of the intended target. Match Move compensates for inter-group position offsets
and provides the option to attach one object to another or to mimic the source object’s
transformations. For more information about the Match Move behavior, see Intro to match
moving in Motion.
You can also link to the group’s coordinates instead of the object’s, and use the Offset
parameters in the Link behavior to obtain the position you want. However, if that group is
subsequently added to another group, the linked object might not move as expected.
Tip: You can make coordinated animations using text layers. For example, link the Scale
parameter of a rectangle (the target object) to the Object Size of a text layer (the source
object) to create an animation in which the rectangle automatically changes its size based
on the size of the text string. Use the Link behavior together with the Align To behavior to
create a box that automatically fits whatever text is typed “into” it.
Note: When a link behavior is added, it’s not enabled by default. To activate the behavior,
click the activation checkbox beside the behavior name in the Behaviors Inspector.
Adjust this behavior using the controls in the Behaviors Inspector:
• Source Object: An object well that defines the source object in which the source
parameter resides. Click the To pop-up menu to select a source object in the current
project.
• Source Parameter (Compatible Parameters): A pop-up menu and assignment field
showing the parameter that serves as the source for the Link behavior. Click the pop-
up menu to choose a new source parameter. Only parameters with the same value type
and number of attributes as the parameter selected in the Apply To (Target Parameters)
pop-up menu appear here.
When a text layer is used as a source, additional parameters appear.
Note: When possible, Source Parameter defaults to the parameter chosen in the Apply
To row (described below).
Important: Changing the Apply To (Target Parameters) setting changes which
parameters appear in the Source Parameter pop-up menu. If you can’t find the
parameter you’re looking for, you might need to choose a target parameter.
• Apply To (Target Parameters): A pop-up menu and assignment field showing the
parameter affected. Click the pop-up menu to reassign the behavior to another
parameter.
When a text layer is used as a target, additional parameters appear.
• Apply Mode: A pop-up menu that sets how the values from the source parameter affect
the target parameter. The choices include:
• Add to source: Adds the source parameter value to the existing value of the target
parameter.