Feature Scope in Multibody Parts
For some features in multibody
parts, you specify which bodies you want the feature to affect.
of cut extrude feature scope
You must create the body to which you want to add the features
prior to adding those features.
All
bodies. Applies the feature to all bodies every time the feature
regenerates. If you add new bodies to the model that are intersected by
the feature, these new bodies are also regenerated to include the feature.
Selected
bodies. Applies the feature to the bodies you select. If you add
new bodies to the model that are intersected by the feature, you need
to use Edit Feature to edit the
extrude feature, select those bodies, and to add them to the list of selected
bodies. If you do not add the new bodies to the list of selected bodies,
they remain intact.
Auto-select.
(Available if you click Selected bodies).
When you first create a model with multibody parts, the feature automatically
processes all the relevant intersecting parts. Auto-select
is faster than All bodies because
it processes only the bodies on the initial list and does not regenerate
the entire model. If you click Selected
bodies and clear Auto-select,
you must select the bodies in the graphics area you want to include.
Solid
Bodies to Affect 
(Available if you clear Auto-select). Select the bodies to affect
in the graphics area.