Assuming a somewhat realistic simulation | Official Unity Discord | Page 1

karmic venture Sep 13, 2022, 2:18 AM

#

Then you apply the maximum engine force in the opposite direction of the motion until v = 0. If you stop firing the engine at exactly the right time, you hit 0 perfectly

#

there is no "correct" amount of force you'd apply to reach 0 velocity. Any amount of force (big or small) will get you there

golden sapphire Sep 13, 2022, 2:19 AM

#

var velo = rb.velocity;
var v2 = velo.sqrMagnitude;
if (v2 > 0.01f)
{
    var v = velo.magnitude;
    var m = rb.mass;
    var ddt = 2 * v * m;
    var ddtAmp = ddt * ddt; * 59f; // amplified 59f because we're targeting 60fps so we can amplify the applied force
    var jpf2 = jpf * jpf;
    if (ddt2 > jpf2)
    {
                    
    }
} else
{
    rb.velocity = Vector3.zero;
}```

#

Also I set Time.maximumDeltaTime = 1f / 60f;

#

I'm trying to simulate a jetpack bring the astronaut to a complete stop.

karmic venture Sep 13, 2022, 2:20 AM

#

you should not multiply your force by anything depending on your framerate

golden sapphire Sep 13, 2022, 2:20 AM

#

karmic venture you should not multiply your force by anything depending on your framerate

I disagree. Why do you say not?

karmic venture Sep 13, 2022, 2:21 AM

#

golden sapphire I disagree. Why do you say not?

you're welcome to disagree, but you are wrong.

It will introduce a framerate dependence into your game. AddForce already accounts for framerate

golden sapphire Sep 13, 2022, 2:21 AM

#

I'm trying to simulate a jetpack bring the astronaut to a complete stop.
Like when there is no input I want a damping effect.

karmic venture Sep 13, 2022, 2:21 AM

#

if you start messing with stuff based on framerate, you'll be undoing that

golden sapphire Sep 13, 2022, 2:23 AM

#

karmic venture you're welcome to disagree, but you are wrong. It will introduce a framerate de...

It's true from the docs changes the velocity by the value of force * DT / mass but if we already know that the time between then next tick will have a limited duration. I think it works.

karmic venture Sep 13, 2022, 2:23 AM

#

if(rb.velocity.sqrMagnitude > 0.01f)
{
  rb.AddForce(dampingForce * (-rb.velocity.normalized));
}
else
{
  rb.velocity = 0;
}

golden sapphire Sep 13, 2022, 2:24 AM

#

karmic venture ```cs if(rb.velocity.sqrMagnitude > 0.01f) { rb.AddForce(dampingForce * (-rb.v...

this does not account for DT or T

karmic venture Sep 13, 2022, 2:24 AM

#

golden sapphire this does not account for DT or T

AddForce does it internally

golden sapphire Sep 13, 2022, 2:24 AM

#

Or it does because AddForce account for it.

karmic venture Sep 13, 2022, 2:24 AM

#

you don't need to do anything for dt or t

#

and you should not

golden sapphire Sep 13, 2022, 2:24 AM

#

I disagree

karmic venture Sep 13, 2022, 2:24 AM

#

okay, you're welcome to do whatever you like

golden sapphire Sep 13, 2022, 2:25 AM

#

Because the formula in the docs DECREASES the F

karmic venture Sep 13, 2022, 2:25 AM

#

yes, it multiplies it by the fixed timestep

#

which is what it is SUPPOSED to do

golden sapphire Sep 13, 2022, 2:25 AM

#

But if we have more available

karmic venture Sep 13, 2022, 2:25 AM

#

that number is like 0.2

#

more what available?

golden sapphire Sep 13, 2022, 2:25 AM

#

thrust

#

or f

karmic venture Sep 13, 2022, 2:26 AM

#

🤦‍♂️

golden sapphire Sep 13, 2022, 2:26 AM

#

What?

karmic venture Sep 13, 2022, 2:26 AM

#

you literally passed in the amount of force to use

golden sapphire Sep 13, 2022, 2:26 AM

#

Force isn't time based?

karmic venture Sep 13, 2022, 2:26 AM

#

acceleration = force * time

#

in this case

#

time is Time.fixedDeltaTime

#

which is small

golden sapphire Sep 13, 2022, 2:27 AM

#

I'm not trying to be diffacult here I swear I'm literally trying to understand.

karmic venture Sep 13, 2022, 2:27 AM

#

so the acceleration is smaller than the force

#

because the timestep is small

golden sapphire Sep 13, 2022, 2:27 AM

#

So we apply more F

#

if available

karmic venture Sep 13, 2022, 2:27 AM

#

you decide what force is available

#

you should pass in whatever you think is available

#

that has nothing to do with AddForce or the time step or anything

#

that's just what number you decide is the amount of force the thing can output

#

and definitely has nothing to do with framerate

golden sapphire Sep 13, 2022, 2:29 AM

#

So lets imagine an "engine" with a max force of 1 in all directions

karmic venture Sep 13, 2022, 2:29 AM

#

then you pass 1 into AddForce

#

the end

golden sapphire Sep 13, 2022, 2:30 AM

#

What is v

#

velocity

karmic venture Sep 13, 2022, 2:30 AM

#

I don't know where you got that equation

#

it is nonsense

golden sapphire Sep 13, 2022, 2:30 AM

#

It's supposed to be P

karmic venture Sep 13, 2022, 2:30 AM

#

it has nothing to do with the physics you're asking about

golden sapphire Sep 13, 2022, 2:30 AM

#

momentum?

karmic venture Sep 13, 2022, 2:30 AM

#

v*m is momentum

#

but that has nothing to do with what you're asking about

golden sapphire Sep 13, 2022, 2:31 AM

#

Okay let me do some more reading. Is it okay if I ping you later?

karmic venture Sep 13, 2022, 2:31 AM

#

please dont

golden sapphire Sep 13, 2022, 2:31 AM

#

diick

#Assuming a somewhat realistic simulation