Adjust turn rate by forward momentum (speed)

Questions & Answers
1

I’m trying to make a little sailing simulation. I’m not interested in dead-on realistic physics, just something that approximates the feeling. So far I’ve just got movement speed and turn rate based on mouse position:

var speedSensitivity = 1;
var rudderSensitivity = 1;

function Update () {

//Get the mouse position and convert it to a manageable number with 0,0 being the center of the screen
var mouseY = ((Input.mousePosition.y - (Screen.height / 2)) / Screen.height)*512;
var mouseX = ((Input.mousePosition.x - (Screen.width / 2)) / Screen.width)*32;

//Adjust the values to the sensitivity sliders
var forwardForce = mouseY * Time.deltaTime * speedSensitivity;
var rotationForce = mouseX * Time.deltaTime * rudderSensitivity;

//Add forwardForce to the forward direction of the rigidbody
rigidbody.AddRelativeForce(Vector3.forward * forwardForce);

//Turn by rotationForce
transform.Rotate(0,rotationForce,0);
}

This script works fine for my purposes, but I want to adjust the turn rate based on how fast the ship is moving forward—so at 0 speed, it doesn’t turn at all, and at high speed, it turns a lot (emulating how a rudder works). I gather I need to multiply the rotationForce by some amount of either the absolute velocity or forward velocity of the rigidbody, but how do I detect those values?

P.S. Pretty much total newbie to both programming and Unity; please forgive me if I’ve missed something totally obvious! :slight_smile:

2

Ultimately, it looks like you want to multiply rotationForce by some number, for example by rigidbody.velocity.magnitude.

Perhaps something like this:

var x = rigidbody.velocity.magnitude * SOMENUMBER;
transform.Rotate(0,rotationForce*x,0);

You could set up some other mathematical relationships, and you’ll probably want to tweak this until it feels right, but I assume that’s the basic idea you’re looking for?