unity 3d student

Beginner B00 – Adding Mass / Gravity with Rigidbodies

How to add gravity / mass to an object using a Rigidbody component

Further Reading

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    I’m using the Unity iPhone 2.6 Editor. It seems the “iPhone standard assets” Box Collider doesn’t include default ‘Physic Material’ options. For example I cannot add bounce. None seems to be my onlyis option.

    How would I get around this issue?


    • Tomo, presumably this just means the asset isn’t included in iphone standard assets – however you can make them yourself using the Create button on the Project panel, then look at the component reference to figure out how to make a Bouncy Physic material. It’ll be a good exercise to help you figure out making such assets from scratch! good luck!

    Sorry I meant to say in my last post that Unity 2.6 was actually Unity iPhone 1.7.

    Anyway I poked around the scripting reference and found a work around via attaching a script to the cube.

    var bouncyness : float = 1;

    function Start () {
    var mat : PhysicMaterial = collider.material; // short for gameObject.collider…


    • Thanks for posting the code! ^^

    I definitely love the format of the tutorial! I’m looking forward to running through a variety of these topics and the challenges as well.

  • just have to say that this is a great website:)

  • Using Unity3….and ‘trying’ to follow this tutorial, but alas; my ‘rigid body’ passes through the ‘floor’ cube every time I press ‘play’?? I add the component to the cube, set to ‘bouncy’, but the rigid body never seems to react with the ‘floor’ cube.

    I enjoy and appreciate these ‘stepped’ tutorials, keep up the great work!

    • is the RB intersecting the floor when the game starts, or do you have the floor collider component set to ‘is trigger’ in the inspector?

      • Solved it somewhat myself by rethinking my approach with typing, “Unity3″….I was using the ‘default’ BootCamp.unity project and a ‘new Scene’…once I ‘restarted’ and generated a ‘new project’ as the tutorials do…my Rigid Bodies are reacting as the tutorial describes!

        …what I get for thinking, ‘advanced’, when I’m just learning to crawl in Unity…been a Torque’master’ for some time now and wanted to start looking at Unity…nice! I likes it! LOL.

        Thanks for the quick reply and offer of assistance, I appreciate that as well!

    Hi Will. I’m second year IMP.

    How do i get the Assets for the bounce? It’s way over my head!

  • don’t worry. figured it out. for anyone else who can’t do it go to: assets -> import package -> applications -> unity -> standard assets -> and it’s the physics materials package not the standard assets (mobile) which was what got me confused

  • I’m using Unity 3.1 with Mobile, and had the same problem with getting the bounce to work. I wrote the following C# code and attached it as a component to my Game Object:

    using UnityEngine;
    using System.Collections;

    public class BounceScript : MonoBehaviour {

    float myBounciness = 1;

    // Use this for initialization
    void Start () {
    PhysicMaterial mat = collider.material;
    mat.bounciness = myBounciness;

    // Update is called once per frame
    void Update () {


  • Nice Work

  • Best Unity tutorial site! =D

  • Fantastic! Just what I need to get me started. I have taught Flash games to high school students for a while. And I’ve figured for some time now that I should be moving into 3D games. We’ve been using Maya for a couple of years, and so combining this with Unity makes a lot of sense. But where to go to get kick started? Wasn’t too long before I found your site. It’s just perfect. Really well taught. Thanks a lot.

    • Great, thanks John 🙂

    Man, you are awesome, thanks a lot.

  • thanks for tutorials
    IN one day i learn unity’s esentials 🙂 thanks again 😉

    • cool! 🙂

    It’s really important to not to forget to put the light in! Otherwise, it looks like the box is falling through the floor. (it’s not falling– it’s just sitting on the floor, but you can’t tell that when there is no light!)

  • The youtube video for this episode is broken, it won’t load up no matter how I try.

  • thanxx for your tutorial but i can’t find anything in my box collider pannel there is no bouncy or any other option in there

  • […] week I continued my skill building by following this set of Unity tutorials. The tutorials ranged from using rigidbody on shapes to creating GUI text. […]

  • sorry , i can create physic material . but i don’t know about rotation . when box collider on the floor .

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