How to make this type of controller with only one shape node and one transform node?
Note: Display->shapes is checked in Outliner
I would try parent command with shape flag but after checked the display->shapes in outliner it will show three nurbscircle shape nodes under one transform node.
How to achieve underlying controller?
Dont know if it is possible to get one curve only to show up like that in the outliner if you unless you turn off shape nodes.
You could try this.
create your curves.
Make sure shapes is ticked in the outliner display.
freeze transforms on the curves.
create an empty group.
select your curveshapes. /expand the nodes and select only the shape nodes and last your empt group.
run parent -r -s; in the commandline.