Reference Cinema 4D Cinema 4D Prime Object Manager View
Function available in CINEMA 4D Prime, Visualize, Broadcast, Studio & BodyPaint 3D

Set As Root

Defines the selected object as the root, i.e., only this hierarchy branch is displayed in the Object Manager. You can also set an object as the root by clicking on the object with Alt+Ctrl held down.

To make navigation in the Object Manager easier, you may find it helpful to activate the Show Path Bar option), which displays the hierarchy path for the branch.