Insert
Sub-Part 
Insert 
Sub-Part
Use this command to create a new part in the active file and instance it into the active part as a component that does not show up in the Assembly Manager nor in the active file's root object list. It is automatically deleted when the parent part is deleted, and may be flagged with "Auto Regen" on or off. Sub-parts are merged with their parent parts automatically.
When it is selected for object-edit, a popup menu is displayed that is the normal menu for a feature along with an "Auto Regen" command. Be sure to review the Notes section below for more about this command.
Auto Regen - The inserted Sub-Part will regenerate when its parent part is regenerated.
The Insert Sub-Part command may be considered
as a way to create a chunk of geometry with its own history as a "sub
item" of the active part -- that is, a "sub-part feature."
The sub-part
history may, or may not, be regenerated when the parent part is regenerated,
depending on the sub-part's "Auto Regen" setting.
If the sub-part
is not flagged for "Auto Regen", its existing geometry is re-merged
into the parent part each time the parent part is regenerated. This
speeds up regeneration of the parent part because the sub-part geometry
does not have to be regenerated each time. It
isolates the sub-part geometry until you decide to reflect changes to
sub-part geometry into the parent part.
You must decide
whether to flag the sub-part for automatic regeneration each time its
parent is regenerated, particularly if the sub-part references geometry
or variables from the parent. Even
if the sub-part is driven by parent geometry, you may choose to disable
regeneration of the sub-part until he is ready to "synchronize"
the sub-part with the parent part, or vice-versa.
The sub-part mechanism is a good way to isolate the steps of importing and healing imported geometry from the main part history -- so that these steps are not re-executed every time the main history is regenerated.
