Getting horizontal velocity of rigidbody on slope

Unity Engine
, ,
1

Hi. I’m trying to make a character movement script which allows the player to move freely on any surface. My problem is that the player doesn’t accelerate nor decelerate when the player goes vertically on a wall. Any idea what’s the problem? Here’s my code:

private void Move()
{
    Vector3 targetSpeed = movement * speed;

    Vector3 speedDif;
    
    speedDif = targetSpeed - Vector3.ProjectOnPlane(Vector3.Scale(Vector3.ProjectOnPlane(new Vector3(1, 0, 1), groundNormal), rb.velocity), Vector3.up);

    float accelRateX;
    float accelRateZ;

    if (groundCheck.Length > 0)
    {
        accelRateX = (Mathf.Abs(targetSpeed.x) > 0.01f) ? acceleration : deceleration;
        accelRateZ = (Mathf.Abs(targetSpeed.z) > 0.01f) ? acceleration : deceleration;
    }
    else
    {
        accelRateX = (Mathf.Abs(targetSpeed.x) > 0.01f) ? acceleration * airAccelMultiplier : deceleration * airDecelMultiplier;
        accelRateZ = (Mathf.Abs(targetSpeed.z) > 0.01f) ? acceleration * airAccelMultiplier : deceleration * airDecelMultiplier;
    }

    Vector3 finalVel = Vector3.Scale(speedDif, new Vector3(accelRateX, 0, accelRateZ));

    rb.AddForce(Vector3.ProjectOnPlane(finalVel, groundNormal), ForceMode.Force);

    Debug.Log($"finalVel: {finalVel}");
    Debug.Log(Vector3.ProjectOnPlane(movement, groundNormal));
}

It’s a 3d version of this guy’s 2d platformer controller https://www.youtube.com/watch?v=KbtcEVCM7bw

Also, my character has a “no friction” physics material on and it’s gravity is disabled when climbing slopes.