Many effects in Motion apply specific parameters from one object to another. For example,
the Bump Map filter applies texture from object A to object B. The Orbit Around behavior
causes object C to circle around object D. You set these object relationships using a
control known as a source well (sometimes called an Image well). A source well is an empty
box into which you drag a source object to influence a target object.
To use a source well
Drag an object from the File Browser, Library, Layers list, or Media list into the empty box.
The name and a thumbnail of the source object appears in the well and is used as a source
for the effect.
To replace the contents of a source well
Drag an object onto the well.
The old source is replaced with the new one.
To clear a source well
Drag the icon in the well out.
The well is emptied.