Question I want to take only the rotation of the Y axis, not the X and Z axes, without constraining the posit

In that case you should use a simple virtual camera:

 

You can keep the FreeLook and put DoNothing in Aim for Top, Middle, and Bottom rigs. That will allow the camera to orbit, but its rotation will remain constant. Then, you can add a custom Aim behaviour to rotate the camera Y only.

Alternatively, you can make a custom extension to lock the X and Z rotation of the camera. Here is one that locks the Y position. You can modify it to lock the X and Z rotations instead.

Code (CSharp):

1. using UnityEngine;
2. using Cinemachine;
3.  
4. /// <summary>
5. /// An add-on module for Cinemachine Virtual Camera that locks the camera's Y co-ordinate
6. /// </summary>
7. [SaveDuringPlay] [AddComponentMenu("")] // Hide in menu
8. public class LockCameraY : CinemachineExtension
9. {
10.     [Tooltip("Lock the camera's Y position to this value")]
11.     public float m_YPosition = 10;
12.  
13.     protected override void PostPipelineStageCallback(
14.         CinemachineVirtualCameraBase vcam,
15.         CinemachineCore.Stage stage, ref CameraState state, float deltaTime)
16.     {
17.         if (stage == CinemachineCore.Stage.Finalize)
18.         {
19.             var pos = state.RawPosition;
20.             pos.y = m_YPosition;
21.             state.RawPosition = pos;
22.         }
23.     }
24. }
25.  

 

I am confused about what you're trying to do. I thought you wanted to constrain the camera rotation, but instead you are constraining the position.

Are you looking for a camera that rotates around the player only horizontally but not vertically? If so, then replace the FreeLook with a VirtualCamera set up like this:



If that is not what you want, please describe the desired camera behaviour more carefully. A picture or diagram would be helpful.

 

It would be freeLook.GetRig(n).LookAt, where n = 0...2