How do I limit rigidbody2d velocity?

Questions & Answers
1

I’m trying to limit my characters speed but nothing I try works. Here’s my current code:
#pragma strict

var force : Vector2;
var bike : Transform;
var power : int;
var brake : int;
var maxForward : int;
var trigfunction : Vector3;

function Update () {
trigfunction = bike.TransformDirection(Vector3.right);

force.Set(trigfunction.x,trigfunction.y);

if (GetComponent.<Rigidbody2D>().velocity.magnitude < maxForward)
	GetComponent.<Rigidbody2D>().AddForce(force);

if (Input.GetKey(KeyCode.UpArrow))
GetComponent.<Rigidbody2D>().AddForce(force*power);

if (Input.GetKey(KeyCode.DownArrow))
GetComponent.<Rigidbody2D>().AddForce(force*brake*-1);
}

What’s wrong?

2

You can check the velocity with velocity.magnitude. If the velocity is too high, disable the forces on the object until it becomes low enough again.

3

To manually force it to a speed, multiply “too fast” velocities by whatever fraction you need to reduce it to the maximum. For example:

float curSpeed = vel.magnitude;
if(curspeed>maxSpeed) {
  float reduction=maxSpeed/curSpeed;
  vel *= reduction;
}

Suppose the max speed is 5, and you’re going 6 now. That code would multiply the entire xyz velocity by 5/6ths. Which really does reduce the speed by 5/6ths, to give a speed of 5 in whichever direction. It’s a common Vector trick.