[Solved] rigidbody.velocity += tweak not working in Unity 5

Nine_Tales · January 10, 2017, 12:43pm

I know I shouldn’t be using Unity 5.5.0f3 however I have gone this far and it is too difficult to start over!

Expected Behavior:

Random movement with the addition of tweak on velocity

Steps to Reproduce:

I have written what Ben has written -

void OnCollisionEnter2D(Collision2D collision)
{
    Vector2 tweak = new Vector2(Random.Range(0f, 0.2f), Random.Range(0f, 0.2f));
    if (hasStarted)
    {
        GetComponent<AudioSource>().Play();
        rigidbody2D.velocity += tweak;
    }
}

rigidbody2D.velocity += tweak; <-- no longer works in Unity 5. I get the error Component rigid2Dbody has been deprecated. Generally when I run into these issues someone has already addressed this issue however I don’t see this issue addressed exactly.

Things I have tried:

(as suggested by editor) Changed rigidbody2D.velocity += tweak; to…
GetComponent().velocity = new Vector2 () + tweak;

Result - Once the ball collides with anything the ball loses all momentum and comes to a complete stop

List item

Changed rigidbody2D.velocity += tweak; to…
GetComponent().velocity = new Vector2 (2f, 10f) + tweak;

Result - (same as above) Once the ball collides with anything the ball loses all momentum and comes to a complete stop

Finally…

public Rigidbody2D rb;

void Start() {
rb = GetComponent();
}

void Update() {
rb.AddForce(transform + tweak);
}

This just gave me errors.

Please help! Thank you!

AndrewD2 · January 10, 2017, 5:35am

You already have the idea there. You need to GetComponent<Rigidbody2D>().velocity += tweak;

ninjachimp · January 10, 2017, 6:19am

Here’s mine, working in Unity 5.

github.com

NinjaChimpStudios/DojoBreaker/blob/master/Assets/Scripts/Ball.cs

using UnityEngine;
using System.Collections;

public class Ball : MonoBehaviour {
	
	private Paddle paddle;
	private bool hasStarted = false;
	private Vector3 paddleToBallVector;

	// Use this for initialization
	void Start () {
		paddle = GameObject.FindObjectOfType<Paddle>();
		paddleToBallVector = this.transform.position - paddle.transform.position;
	}
	
	// Update is called once per frame
	void Update () {
		if (!hasStarted) {
			// Lock the ball relative to the paddle.
			this.transform.position = paddle.transform.position + paddleToBallVector;

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Nine_Tales · January 10, 2017, 5:01pm

Thanks guys. @ninjachimp @AndrewD2

I think I had tried this early on but it didn’t seem to be adding much randomness to the ball’s velocity. It seemed to be affecting Ben’s ball more so this time I added a larger number to the randomness just to check it was working and it seemed to move a lot more when I increased the range on random.range. The 0.2 alters movement very slightly. I reverted the randomness back to 0.2. I just raised the randomness to verify it was working.

Galandil · January 10, 2017, 4:36pm

A couple of tips to optimize the code:

You don’t need anywhere the keyword this., there’re no hidden variables.
It’s better to declare a general class RigidBody2D variable and give the reference to the component in Start(), and then use the reference elsewhere in the class, GetComponent is a slow method so better to execute it just once if possible.