Another Addforce does nothing thread. (again)

My last post on this was deleted, thank you so much, so I'll try again.

I have the following code which pops a ball into existence and applies a force. Or at least it should.

Code (CSharp):

1.        if (MakeBall)
2.         {
3.             Vector3 f = transform.forward.normalized;  //  Used to move ball free from barrel.
4.             Instantiate(ball, transform.position + (f * 2.2f), Quaternion.identity);  //  Move ball free from barrel
5.             Rigidbody rb = ball.GetComponent<Rigidbody>();      //  Yes it does have one!
6.             rb.AddForce(Vector3.forward * EjectSpeed, ForceMode.Impulse);  //  <<  AAARRRGGGHHH
7.            
8.             MakeBall = false;
9.             EjectTime = Time.time;
10.         }

All is good, the ball is created, but then falls majestically to the floor without a single whiff of forward momentum.

I have spent hours googling 'Addforce does nothing'. There are a LOT of threads. Nearly all of which say I should try using Velocity instead, all the others say I should definitely not use Velocity. There are loads of tubes which show people adding a force to an existing object. I've found nothing for a dynamic object which seems odd as that's what projectiles are going to be, and projectiles need force. And nearly every game has a projectile!

There seem to be no fixes for any of the threads I've found, just explanations of what Addforce does. Or doesn't. Do I need to go back to the dark ages and calculate the physics myself? I chose to move to unity so I didn't have to deal with physics in code anymore.

Could someone please explain why the above doesn't work? I can only assume I'm being a complete ass and I'm missing something very obvious as I've tried absolutely every single combination of force, velocity and shouting.

Many thanks.

 

you are making it hard. attach an empty game object name it muzzle and make it child of barrel and then instantiate ball and add force transform.forward

 

It falls to the ground because you're adding momentum to ball's prefab. And not to the newly created ball.

Instantiate returns result, and that result is the newly created object.

See:

Code (csharp):

1.  
2.             Instantiate(ball, transform.position + (f * 2.2f), Quaternion.identity);  //  Move ball free from barrel
3.             Rigidbody rb = ball.GetComponent<Rigidbody>();      //  Yes it does have one!
4.  
5.  

In those lines you ignore object returned by instantiate, and isntead grab rigibody from prefab object.

 

Ahhhh, so Instantiate doesn't give me a new object called ball.

I need NewBall=Instantiate(....

How is that easier? That's just repeating what I already have with other objects.

 

It can't return your object via "ball" parameter.

See, in C# in this kinda of scenario:

Code (csharp):

1.  
2. void someFuntion(SomeType arg){
3. }
4.  

function can access and alter "arg" object, and if "arg" is of reference type, changes will be visible outside of function:
But. Unless parameter is marked as ref or out, it can't REPLACE "arg" with something else.

Example:

Code (csharp):

1.  
2.  
3. void func1(SomeType arg){
4.     arg = new SomeType();
5. }
6.  
7. void func2(ref SomeType arg){
8.     arg = new SomeType();
9. }
10.  
11. void func3(out SomeType arg){
12.     arg = new SomeType();
13. }
14.  
15. void test(){
16.     var obj1 = new SomeType();
17.     var obj2 = new SomeType();    
18.     var obj3 = new SomeType();
19.     func1(obj1);//obj1 doesn't change
20.     func1(ref obj2);//obj2 replaced with a new object
21.     func1(out obj3);//obj2 replaced with a new object
22. }
23.  

 

It would be very odd if Instantiate changed your local variable "ball". It's possible to do so in functions using the ref keyword, but it wouldn't make sense for a function such as instantiate.

Here's an example. This makes far more sense:

Code (CSharp):

1. var myCopy = MakeCopyOf(someObject);

Than this:

Code (CSharp):

1. MakeCopyOf(ref someObject); // someObject now contains your copy.

Instantiate is essentially a MakeCopyOf.