Parent Hierarchy

Parent Hierarchy

Layer parenting, in which all of the Transform settings
(except Opacity, which isn’t really a Transform setting) are
passed from parent to child, can be set up by revealing the
Parent column in the Timeline. There, you can choose a
layer’s parent either by selecting it from the list, or by dragging
the Pickwhip to the parent layer, and use the setup as
follows:
. Parenting remains valid even if the parent layer moves,
is duplicated, or changes its name.
. A parent and all of its children can be selected by
context-clicking the parent layer and choosing Select
Children.
. Parenting can be removed by choosing None from the
Parent menu.
. Null Objects (Ctrl+Alt/Command+Option+Shift+Y)
exist only to be parents; they are actually 100 × 100
pixel layers that do not render.

You probably knew all of that. You might not know what
happens when you add the Option key to Parent settings:
. Hold Option as you select the None option and the
layer reverts to the Transform values it had before
being parented (otherwise the offset at the time None
is selected remains).
. Hold Option as you select a Parent layer and its Transform
data at the current frame applied to the child
layer prior to parenting.
This last point is a very cool and easily missed method for
arraying layers automatically. You duplicate, offset, and
parent to create the fi rst layer in a pattern, then duplicate
that layer and Option+Parent it to the previous duplicate.
It behaves like the Duplicate and Offset option in Illustrator