Question AddForce...

Can somebody explain to me please how is it that if I AddForce upwards to a RigidBody on GetKey and hold the key down, the object goes up and then starts falling down? How is it that accumulated AddForce force wins over gravity and accelerates the object upwards but eventually loses? And then once it goes down enough the upwards force wins over the gravity again and the object goes up again but heigher than before and then it falls down again and then goes higher again than the previous time?

Because it does not make sense to me at all.
Any insight on this would be very appreciated.

 

What's your code? When and how often are you calling AddForce?

 

This is the code:

void Start(){
playerRb = gameObject.GetComponent<Rigidbody>();
Physics.gravity *= gravityModifier;
}

void FixedUpdate(){
if (Input.GetKey(KeyCode.Space) && !gameOver){
playerRb.AddForce(Vector3.up * floatForce);
}
}

Update - FixedUpdate makes no difference on the outcome.
floatForce is set to 50;
mass of the object is 1
drag is 0
angular drag is 0.05
gravity is used
iskinematic is false

 

What is your "gravityModifier"? And is this script attached to more than one object? Because each object would multiply the global gravity. So this may be your issue. If the gravity is set to the default 9.81 m/s² and you multiply it by a value larger than 1, the gravity would get stronger with each object.

I would highly recommend to not apply such relative changes to gravity. If you really need to do that, do it at a central location from a manager where you know that it's only called once. But even then you should not do a relative change like that. What if you reload your level? That would not reset the gravity setting of the physics system and your Start method would multiply it again.

 

I did not come up with the gravity modifier, it was already in the challenge:
https://learn.unity.com/tutorial/ch...578eb67df&projectId=5cf9639bedbc2a2b1fe1e848#

Anyhow, I reopened the project one week later and all is OK. The ballon goes up infinitely. I don't know how it is possible if I did not change anything.

Thank you for trying to help!

 

How unfortunate... that really is a dreadful approach for Unity to have chosen.

@MarcinSok You might want to move on to some better tutorial creators because there's a lot of issues with that particular Learn package.

Personally I really like this guy... here's his intro video and he has a metric buttload of amazing tutorials:

Imphenzia: How Did I Learn To Make Games:

Here's his main "how to code," plus a few more creators too:

Imphenzia / imphenzia - super-basic Unity tutorial:

Jason Weimann:

Brackeys super-basic Unity Tutorial series:

Sebastian Lague Intro to Game Development with Unity and C#: