Rotating 3rd Person Character Programmatically from Unity's Standard Assets - unity3d

Question

I am trying to automate a random rotation of a 3rd person character in Unity and I'd like the rotation to be animated as if I were turning the player myself using the out of the box controller and the WASD keys. The goal is an NPC that randomly rotates, looking for someone in a crowd.
Here is what I've attempted thus far, within a coroutine in update.
float xDegress = Random.Range(10f, 75f);
float yDegress = Random.Range(10f, 75f);
float zDegress = Random.Range(10f, 75f);
// Works but immediate
this.transform.Rotate(0f, yDegress, 0f);
// Works but immediate
this.transform.LookAt(new Vector3(xDegress, 0f, zDegress));
// Doesn't work
rB.rotation = Quaternion.Lerp(transform.rotation, new Quaternion(0, yDegress, 0, 0), 0.5f);
// Doesn't work
rB.MoveRotation(new Quaternion(0, yDegress, 0, 1).normalized);
// Works but immediate
Vector3 newPosition = new Vector3(xDegress, 0f, zDegress);
transform.rotation = Quaternion.Lerp(
transform.rotation,
Quaternion.LookRotation(newPosition, Vector3.up),
0.5f);
yield return new WaitForSeconds(_pauseSeconds);
Here's the inspector for the NPC, which is Ethan from the standard assets.

Answer 1

First of all since it is a RigidBody you shouldn't use transform.rotation = nor any transform. method at all but stick to rb.MoveRotation or rb.rotation.
Than you used Lerp in a "wrong" way. What you want is a value that grows from 0 to 1. Calling it only once with a factor of fixed 0.5f allways results in a rotation halfway inbetween the first and the second
one - immediately.
First you need a desired duration for the rotation.
// How long in seconds should the rotation take?
// might be a constant or set via the inspector
public float rotationDuration = 1.0f;
Than before you start rotating get the start and end rotation
float xDegress = Random.Range(10f, 75f);
float yDegress = Random.Range(10f, 75f);
float zDegress = Random.Range(10f, 75f);
var currentRotation = transform.rotation;
var targetRotation = currentRotation * Quaternion.Euler(xDegress, yDegress, zDegress);
// or
Vector3 newPosition = new Vector3(xDegress, 0f, zDegress);
var targetRotation = Quaternion.LookRotation(newPosition, Vector3.up);
// or whatever your target rotation shall be
Now since you already are in a Coroutine you can simply add a while loop performing the rotation within the desired duration (don't forget the yield though)
var passedTime = 1.0f;
while(passedTime < rotationDuration)
{
// interpolate the rotation between the original and the targetRotation
// factor is a value between 0 and 1
rb.MoveRotation = Quaternion.Lerp(currentRotation, targetRotation, passedTime / rotationDuration);
// add time passed since last frame
passedtime += Time.deltaTime;
yield return null;
}
// to avoid overshooting set the target rotation fix when done
transform.rotation = targetRotation;
yield return new WaitForSeconds(_pauseSeconds);