Apply force vs Apply Impulse?

While writing a suggestion about “Apply Force”, I realised that maybe there was something I had misunderstood…

In Physics2 “Apply Force” needs to be performed every frame, and does not seem to take in accound the frame duration. So it actually behaves like an impulse (fixed amount of push, given once). So, what is the difference with Apply Impulse ?

When should you use one or the other ?
I am missing something ?

Hi, I have read your post in the “General”-section and I cannot really give you a good explanation of what is going on. That computers have different specs that influence the frame rate is a general problem and you have found the solution to use TimeDelta() for getting around that issue.

I guess you have searched a bit and there are some good explanations about the difference between force and impulse: an impulse is instantly applied to the object, a force in contrast is building up and it also takes other forces (in case of your rocket it is probably gravity) into account.

As far as I understood, force requires more calculations and that could be the reason why it is not working well on your low frame rate computers. I have no knowledge about how physics simulations work in general and in Gdevelop. But I have read that physics calculations don’t need to be necessarily in sync with the frame rate. But again, I am just guessing here and I hope that someone who knows better what is going on can give an explanation.

[ But I have read that physics calculations don’t need to be necessarily in sync with the frame rate.]
Indeed. That’s what I was expecting too. It would, if “apply force” was frame rate independent, ie its effect would depend on the time length it is applied, and not the number of frame as it seems to be now.

Which is why I was wondering if it worked as designed, or if I missed something.