How to calculate the gravity of a Rigid Body without Godot's Physics?

TheDiavolo

In a proof of concept I'm doing for a personal project, it's a KSP-like space rocket simulator

And I want to simulate the gravity that the rockets had with the planet at this moment

What am I doing?

Create a class called CelestialObject that will be the class for the planets, extend RigidBody and in the _physics_process function with a dictionary I run through a list in which the Rigid Bodies that will be affected by the gravity of this planet are stored and each one I apply a force centered with the planet's gravity and to the direction in which it is

Code: func _apply_gravity(object: RigidBody, delta: float): var force: Vector3 = Vector3(0, object.mass -Gravity delta, 0).direction_to(self.transform.origin) object.apply_central_impulse(force)

What is the problem? that the body moves too slow

Why don't I use an Area and check the gravity point box for it? That was the idea, but a problem arose that did not let me continue with it, the spherecollisions have a maximum size that I do not remember right now and in my proof of concept I want to represent the planets 1: 1

He also had another alternative which was to generate a concavecolillon based on a Mesh Instance, but the point of gravity did not work with him

I could go to Unity since there are many examples of how to do planet physics without problems and also where KSP was created, but I do not know the Engine very well and I would prefer it to be godot since I have more control and I know how it works

cybereality

This is a math problem, it really has nothing to do with the engine. Gravity is an acceleration, so you want to use the function add_force rather than apply_central_impulse (impulses are for hits like kicking a box or a bullet hitting a wall). https://docs.godotengine.org/en/stable/classes/class_rigidbody.html#class-rigidbody-method-add-force

pigna

I think your physics formula is wrong. For gravity: |F| = G (mass1 mass2) / r^2. What I see in your script is: |F| = mass2*-Gravity (I have no Idea what 'Gravity' is). This should be the correct function:

func _apply_gravity(object: RigidBody,  delta: float):

	# the following lines calculate the distance vector, 
	#its direction and its module squared
	var distance = self.translation - object.translation
	var direction =  distance.normalized()
	var dist_sqrd = distance.length_squared() 
	
	# G would be a global constant that controls the intensity of gravity
	# NOTE: you need to multiply by the mass of the PLANET, 
	#not the object (assuming its mass is negligible)
	var force = G * self.mass / dist_sqrd 
	
	# direction: Vector3 * force: float = force_vector: Vector
	object.apply_central_impulse(direction*force)`