Resolved Rigidbody.GetAccumulatedForce()

When you add a force, it doesn't get added there and then but is added to a sum. When the simulation runs, it's time-integrated into velocity and that sum is reset. At any point you can ask what the current accumulated force is.

As per the simple code example in the doc, it adds a force, reads what the current force total is then adds the same but negative, effectively subtracting it and cancelling and force that was previously added.

 

It's such a simple call that just reads the accumulator of forces you've asked to add. Beyond that, it'll be whatever else you're doing causing you an issue. Don't make it difficult by applying a force in one script then trying to do something in another, potentially in the wrong order? You can easily test this in a simple script as per the example so you understand first. Walk before you run and all that.

Ever wondered where the force you're asking to add when calling AddForce is stored? Here. It's allowing you to read it. If you thought that calling AddForce as a force immediately did something to the velocity then that's incorrect.

It's not a "way to simulate a rigidbody slowing down". It doesn't have any active role in anything. It's just a read-only value which you can use for whatever you need; it just tells you what you've added so far since the last simulation step used it and cleared it.

Add a force of (10, 0, 0) then you'll read (10, 0, 0). Add another force of (1, 1, 1) and you'll read (11, 1, 1). After the simulation step, you'll read (0, 0, 0). It couldn't be more simple really.

Why turn off gravity in the example? Because the example is showing you that it's stopping the user force added in the example from having any effect on velocity by reading it and apply the inverse of it, effectively cancelling it out. Gravity would get in the way of that example right? Gravity is not a user force, in-fact it's not a force at all, it's an impulse as are all of the collision contact and joints responses. The only forces are the ones you specify, time-integrated into velocity for you by the engine.

In 2D we have:
https://docs.unity3d.com/ScriptReference/Rigidbody2D-totalForce.html
https://docs.unity3d.com/ScriptReference/Rigidbody2D-totalTorque.html

Note, I'm not a 3D physics dev so I only noticed this after reading the post above and looked at the docs myself.

Hope that rambling explanation helped a little!

 

Good stuff, glad it's working for you. I was starting to doubt it worked....