Climbing wall Script?

Try this :

 using UnityEngine;
 using System.Collections;
 
 public class MYCLASSNAME : MonoBehaviour {
 
 
 Transform chController;
 bool  inside = false;
 float heightFactor = 3.2f;
 
 private FPSInputController FPSInput;
 
 void  Start (){
     FPSInput = GetComponent<FPSInputController>();
 }
 
 void  OnTriggerEnter ( Collider Col  ){
     if(Col.gameObject.tag == "Ladder")
     {
         FPSInput.enabled = false;
         inside = !inside;
     }
 }
 
 void  OnTriggerExit ( Collider Col  ){
     if(Col.gameObject.tag == "Ladder")
     {
         FPSInput.enabled = true;
         inside = !inside;
     }
 }
         
 void  Update (){
     if(inside == true && Input.GetKey("w"))
     {
             chController.transform.position += Vector3.up / heightFactor;
     }
 }
 [RPC]
 void  Test (){}
 }

You would have to use Physics.CheckSphere or Physics.CheckBox or you can use a trigger to check if the player is near a wall. Then you do a Raycast from the player's position with the player's forward vector to check if the player is facing the wall. If the player is near a wall and is facing the wall then the player can climb the wall. Also don't forget to use a layermask to make sure only climbable object are detected.

Try this:

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent(typeof(Rigidbody))]
 [RequireComponent(typeof(CapsuleCollider))]
 public class ClimbScript : MonoBehaviour
 {
     public float WalkSpeed = 5f;
     public float ClimbSpeed = 3f;
     public LayerMask wallMask;
 
     bool climbing;
 
     Vector3 wallPoint;
     Vector3 wallNormal;
 
     Rigidbody body;
     CapsuleCollider coll;
 
     // Use this for initialization
     void Start ()
     {
         body = GetComponent<Rigidbody>();
         coll = GetComponent<CapsuleCollider>();
     }
     
     void FixedUpdate ()
     {
         if (NearWall())
         {
             if (FacingWall())
             {
                 // if player presses the climb button
                 if (Input.GetKeyUp(KeyCode.C))
                 {
                     climbing = !climbing;
                 }
             }
             else
             {
                 climbing = false;
             }
         }
         else
         {
             climbing = false;
         }
 
         if (climbing)
         {
             ClimbWall();
         }
         else
         {
             Walk();
         }
     }
 
     void Walk()
     {
         body.useGravity = true;
 
         var v = Input.GetAxis("Vertical");
         var h = Input.GetAxis("Horizontal");
         var move = transform.forward * v + transform.right * h;
 
         ApplyMove(move, WalkSpeed);
     }
 
     bool NearWall()
     {
         return Physics.CheckSphere(transform.position, 3f, wallMask);
     }
 
     bool FacingWall()
     {
         RaycastHit hit;
         var facingWall = Physics.Raycast(transform.position, transform.forward, out hit, coll.radius + 1f, wallMask);
         wallPoint = hit.point;
         wallNormal = hit.normal;
         return facingWall;
     }
 
     void ClimbWall()
     {
         body.useGravity = false;
 
         GrabWall();
 
         var v = Input.GetAxis("Vertical");
         var h = Input.GetAxis("Horizontal");
         var move = transform.up * v + transform.right * h;
 
         ApplyMove(move, ClimbSpeed);
     }
 
     void GrabWall()
     {
         var newPosition = wallPoint + wallNormal * (coll.radius - 0.1f);
         transform.position = Vector3.Lerp(transform.position, newPosition, 10 * Time.deltaTime);
 
         if (wallNormal == Vector3.zero)
             return;
 
         transform.rotation = Quaternion.LookRotation(-wallNormal);
     }
 
     void ApplyMove(Vector3 move, float speed)
     {
         body.MovePosition(transform.position + move * speed * Time.deltaTime);
     }
 }

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class WallClimb : MonoBehaviour { Ray ray; public float range = 1f; public float climbspeed = 5f; public float sticktowallforce = 5f;

 // Start is called before the first frame update
 void Start()
 {

 }

 // Update is called once per frame
 void Update()
 {
     RaycastHit hit;

     if (Physics.Raycast(transform.position, transform.forward, out hit, range))
     {
         if (hit.transform.tag == "Wall")
         {
             if (Input.GetKey(KeyCode.Space))
             {

                 transform.position += transform.forward * Time.deltaTime * sticktowallforce;
                 transform.position += transform.up * Time.deltaTime * climbspeed;
                
             }
         }
     }
 }

}