Why does Rigidbody 3d not have a gravity scale?

The rigidbody 2d has a gravity scale to affect falling acceleration.
The rigidbody 3d does not have this.
I have many rigidbody 3d which I would like to fall at different speeds. It seems the simplest way would be to assign a gravity scale and let the game engine/physics system control this.
Other game engines have this functionality, but not Unity.
Does anyone know why this is? What is the work-around to this limitation?
This has been puzzling me for a while now.

Thanks.

 

2D physics and 3D physics use different engines, Box2D and PhysX respectively. Thus, the features and implementation are different.

For 3D physics, the best workaround is to disable "Use Gravity" in the rigidbody and implement gravity by scripting. This simple component provides you a custom gravity scale per object:

Code (CSharp):

1. using UnityEngine;
2.  
3. [RequireComponent(typeof(Rigidbody))]
4. public class CustomGravity : MonoBehaviour
5.     {
6.     // Gravity Scale editable on the inspector
7.     // providing a gravity scale per object
8.  
9.     public float gravityScale = 1.0f;
10.  
11.     // Global Gravity doesn't appear in the inspector. Modify it here in the code
12.     // (or via scripting) to define a different default gravity for all objects.
13.  
14.     public static float globalGravity = -9.81f;
15.  
16.     Rigidbody m_rb;
17.  
18.     void OnEnable ()
19.         {
20.         m_rb = GetComponent<Rigidbody>();
21.         m_rb.useGravity = false;
22.         }
23.  
24.     void FixedUpdate ()
25.         {
26.         Vector3 gravity = globalGravity * gravityScale * Vector3.up;
27.         m_rb.AddForce(gravity, ForceMode.Acceleration);
28.         }
29.     }

 

OK thanks. This works good. Another thing I did was play around with the drag. Increasing the drag seems to produce the desired results.

 

saved my life

 

thank you very much

 

Man, thanks for the script you posted earlier. Definitely a life saver.

 

I would not mess around with drag in this case.
Just turn off gravity for particular object and add custom gravity component.

AddForce(Physics.gravity * scale, ForceMode.Acceleration)

 

Hmmmm. ¿Scale? rigidbody.mass will be better if not then, I guess will be scale * scale * scale.

 

What the hell are you talking about ?

 

Oh, I'm an idiot.
I dont know what I was thinking when I wrote that. I was kinda confused.
I want to end this post with the solution.
So, I guess the solution for @ArachnidAnimal is this little script:

Code (Csharp):

1. using UnityEngine;
2.  
3. [RequireComponent(typeof(Rigidbody))]
4. public class GravityScale : MonoBehaviour
5. {
6.     public float gravityScale = 1f; //The gravity scale
7.     Rigidbody rb;
8.    
9.     void Start()
10.     {
11.         rb = GetComponent<Rigidbody>();
12.     }
13.  
14.     void FixedUpdate()
15.     {
16.         rb.AddForce(Physics.gravity * gravityScale * Time.fixedDeltaTime, ForceMode.Acceleration) //It has to be FixedUpdate, because it applies force to the rigidbody constantly.
17.     }
18. }

This should work.

 

No it should not.
Physics.gravity is already an acceleration, there is no need to multiply it by fixedDeltaTime.

 

Sorry, just I didn't knew it.
Will work without the fixedDeltaTime.

 

For clarification:

Code (CSharp):

1.     using UnityEngine;
2.    
3.     [RequireComponent(typeof(Rigidbody))]
4.     public class GravityScale : MonoBehaviour
5.     {
6.         public float gravityScale = 1f; //The gravity scale
7.         Rigidbody rb;
8.      
9.         void Start()
10.         {
11.             rb = GetComponent<Rigidbody>();
12.         }
13.    
14.         void FixedUpdate()
15.         {
16.             rb.AddForce(Physics.gravity * gravityScale , ForceMode.Acceleration) //It has to be FixedUpdate, because it applies force to the rigidbody constantly.
17.         }
18.     }
19.  

 

Thanks brother