Really simple movement script help

Scripting
1

Ok,

I am what I call an advanced beginner to scripting. However, I have never working with rigid bodies and making my own movement scripts before.

This script is applied to a ‘rocket’. The rocket should rotate around the z axis when the left and right arrows are pressed, and go upwards when up arrow is held down, and when you don’t hold anything, float slowly down.

#pragma strict

var speed : float = 15;
var gravity : float = 1;
var force : float = 10;

private var pos : Transform;
var maxSpeed : float = 100f;//Replace with your max speed

function FixedUpdate()
{
    if(rigidbody.velocity.magnitude > maxSpeed)
    {
               rigidbody.velocity = rigidbody.velocity.normalized * maxSpeed;
    }
}


function Update()
{
	pos = this.transform;
	//transform.rotation.z = 0;
	//transform.rotation.y = 0;
	//transform.position.z = 0;
	
	if(Input.GetKey(KeyCode.RightArrow))
	{
	transform.Rotate(Time.deltaTime * speed, 0, 0);
	} else if(Input.GetKey(KeyCode.LeftArrow))
	{
	transform.Rotate(Time.deltaTime * -speed, 0, 0);
	}
	
	if(Input.GetKey(KeyCode.UpArrow))
	{
    rigidbody.AddRelativeForce (transform.up * force);
	}
}

At the moment, the when trying to get the rocket to move, it moves upwards on a global scale, not local. Also, if you hold up while on the ground, it moves sideways.

2

You are applying your force in the direction of transform.up, which is the object’s y-axis vector in world space, relative to its local space orientation via AddRelativeForce(). If the local orientation basis is not x:<1,0,0> y:<0,1,0> z:<0,0,1>., then this can easily cause unexpected motion.

For example, if the local orientation is x:<0,1,0> y:<1,0,0> z:<0,0,1> and you try to add force in the direction of the object’s world “up” vector via AddRelativeForce(transform.up), then the object will scoot sideways along the x-axis <1,0,0>, because that is its local “up”.

It sounds like that’s not what you want to do. You should use AddForce() instead of AddRelativeForce().

3

Ok, I changed it to AddForce, but it is still not working well.

The rough acceleration is due to the camera script, ignore it.

Web Player

4

The web player isn’t working for some reason. When I click your link, it asks me to install the Unity web plugin, but it is already installed.Other Unity web apps work.

I can’t see what’s on your screen, so I can only guess. But if AddForce(transform.up) still pushes the object sideways, then that strongly suggests that your object’s y-axis vector is actually sideways. That would be the first thing to check.