Question Gravity pull not taken into account in Physics2D.simulate

Hello! I'm new to Unity and I think I'm not getting how Physics2D.simulate works.

I'm trying to implement a trajectory prediction in a 2D outer space game with line renderer using the physics simulation method presented here: https://austin-mackrell.medium.com/unity-trajectory-prediction-simulation-method-5b441ee1604

I implemented as in the post: a physicscene copy of the actual scene is created, clones of the planets and the player are moved there.

Then I run physicsScene2D.simulate method X iterations in the future to make my prediction when the player aims and the line renderer draws at each iteration the simulated player's position.

Here is the simulated launch code:

Code (CSharp):

1. public void SimulateLaunch(Transform player, Vector3 force)
2.     {
3.  
4.         _simulatedPlayer.transform.position = player.position;
5.         _simulatedPlayer.transform.rotation = player.rotation;
6.         _simulatedPlayer.GetComponent<Rigidbody2D>().velocity = Vector3.zero;
7.  
8.         if(_lastforce != force)
9.         {
10.             _simulatedPlayer.GetComponent<Rigidbody2D>().AddForce(force);
11.             for (int i = 0; i < _maxSimulSteps; i++)
12.             {
13.                 _physicsScene.Simulate(Time.fixedDeltaTime);
14.  
15.                 points[i] = _simulatedPlayer.transform.position;
16.                 trajectoryLine.SetPosition(i, points[i]);
17.             }
18.         }
19.         _lastforce = force;
20.  
21.     }

However, I have GameObjects representing planets that exert a gravity pull on my player.

Code (CSharp):

1. void FixedUpdate()
2.     {
3.      
4.  
5.         float distance = Vector2.Distance(player.transform.position, transform.position);
6.         if (distance < influenceRange)
7.         {
8.             pullForce = (transform.position - player.transform.position).normalized * intensity * fixedUpdateCompensator / distance;
9.             player.GetComponent<Rigidbody2D>().AddForce(pullForce, ForceMode2D.Force);
10.         }
11.  
12.  
13.         float distanceToSim = Vector2.Distance(playerSimulation.transform.position, transform.position);
14.         if (distanceToSim < influenceRange)
15.         {
16.             playerSimulation.GetComponent<Rigidbody2D>().AddForce(((transform.position - playerSimulation.transform.position).normalized * intensity * fixedUpdateCompensator / distanceToSim), ForceMode2D.Force);
17.         }
18.  
19.  
20.     }

Every FixedUpdate, these planets calculate the force to exert using a simplified newton's law and addForce to the player's rigidbody.

When aiming: the line renderer is not curved when near to a planet.
But in my actual scene the ship is gravity pulled correctly.



I think i'm maybe missing something about the physics simulate lifecycle and callbacks handling ?
The fixedUpdate seems to be called because if I log inside:

Code (CSharp):

1. if (distanceToSim < influenceRange)
2.         {
3. //Log something
4.         }

It pops in the console.

Any help appreciated, even if it's " read this part of the documentation"