How to rotate GameObjects X and Z to floor normals?

Questions & Answers
1

I’ve got a function that’s called in my update that used the camera rotation and GetAxis to move and rotate the player (long the Y axis). Now I want to to rotate X and Z so that the player is aligned with the slope of the floor beneath them. I’ve gotten as far as detecting the Floor’s Normal but I’m not sure how to translate it into a rotation given my current script. To be clear, nothing in the code is broken, I’m just not quite smart enough to figure out the next step. My function:

void MovementUpdate()
    {
        // Get Input for axis
        float h = Input.GetAxis("Horizontal");
        float v = Input.GetAxis("Vertical");

        // Calculate the forward vector
        Vector3 camForward_Dir = Vector3.Scale(Camera.main.transform.forward, new Vector3(1, 0, 1)).normalized;
        Vector3 move = v * camForward_Dir + h * Camera.main.transform.right;

        if (move.magnitude > 1f) move.Normalize();

        // Calculate the rotation for the player
        move = transform.InverseTransformDirection(move);

        // Get Euler angles
        float turnAmount = Mathf.Atan2(move.x, move.z);

        //get floor normal/slope
        RaycastHit hit;
        Vector3 down = transform.TransformDirection(-Vector3.up) * 0.5f;
        Physics.Raycast(transform.position, down, out hit);

        if (hit.collider.tag != "Player")
        {
            Quaternion groundTilt = Quaternion.FromToRotation(Vector3.up, hit.normal);
            Debug.Log(groundTilt);
        }

        transform.Rotate(0, turnAmount * RotationSpeed * Time.deltaTime, 0);

        _moveDir.y -= Gravity * Time.deltaTime;

        _characterController.Move(_moveDir * Time.deltaTime);
    }
2

This should do the trick:

transform.rotation = Quaternion.LookRotation (Vector3.ProjectOnPlane (transform.forward, hit.normal), hit.normal);

You simply project your current forward direction onto the plane that is defined by the normal at your raycast hit. Then you can use Quaternion.Lookrotation to create a quaternion that is fitting for your current surface.
Of cause you can use the result of Quaternion.LookRotation as a target for Quaternion.rotatetowards or slerp to make your character smoothly apply the surfaces angle instead of abruptly setting it.
Do consider though: I only tested this on a simple curved surfaces.