Use the Center of Rotation: Boundary subnode to select a set of boundaries whose centroid represents the center of rotation.

Use the Center of Rotation: Edge subnode to select a set of edges whose centroid represents the center of rotation.

Use the Center of Rotation: Point subnode to select a set of points whose centroid represents the center of rotation.

These nodes are automatically added when Centroid of selected entities is selected in the parent node. They cannot be added or removed manually.