How to use Look_At() to modify a Rigidbody's Gravity by using RayCast?

Question

(P.S. This requires either the Godot 3.0 Alpha or the Recent Master Source Build for this.)

Hello! I was attempting to create a Science Fiction Racing demo I'm currently experimenting on: ( https://github.com/Corruptinator/G-Zero ). I was using a Rigidbody instead of VehicleBody because I thought this makes it easier to modify the gravity at any given circumstances. The problem now is that to make the gravity rotate or aim in the direction, the Look_At() function is not giving the results I'm trying to achieve for.

Here is the code I was trying to get it to work:

extends RigidBody

# TODO: Fix the gravity, Fix the Rotation, Fix controls.

export var player = false
export var camera = false
var g = 1

func _ready():
    # We set up our physics and the current camera for the scene.
    if camera == true:
        get_node("Position/Rotation/Camera").make_current()
        pass
    elif camera == false:
        get_node("Position/Rotation/Camera").clear_current()
        pass
    else:
        pass
    set_fixed_process(true)
    set_gravity_scale(0)
    pass

func _fixed_process(delta):

    #This part is where the raycast detects where the collision point is in order to re-allign the
    #"Position" to aim at the ground to allow the object to fall towards its own gravity straight into
    #the road beheath. Unfortunately the code is broken and I am still figuring out how "Look_At()" works.
    #If you like to improve/help in this code feel free to do so! Contributions are welcome!
    var ray = get_node("Position/RayCast")
    var a = ray.get_collision_point()
    var b = self.get_global_transform().origin
    #a.z = 0
    #b.z = 0
    #a.y = 0
    #b.y = 0
    var calculate = Vector3(a-b).normalized()

    #print(get_linear_velocity())

    #The code snippet below determines if the variable "ray" is detecting the ground, if it is then this
    #is where the look_at() is put to use to rotate/aim the "Position" node towards the ground, depending on
    #what the "RayCast"'s get_collision_point() says. If the ground is not detected in the "ray" then the
    #"Position" node is reset towards the default rotation at Vector3(0,0,0).

    if ray.is_colliding() == true:
        get_node("Position").look_at(calculate,Vector3(0,1,0))
        #print(calculate)
        #g = -.05
        pass
    else:
        #print("off")
        #get_node("Position").look_at(self.get_global_transform().origin,Vector3(0,1,0))
        #get_node("Position").rotate_x(get_rotation().x*-1)
        #get_node("Position").rotate_y(get_rotation().y*-1)
        #get_node("Position").rotate_z(get_rotation().z*-1)
        #rotate_x(get_rotation().x*-1)
        #rotate_y(get_rotation().y*-1)
        #rotate_z(get_rotation().z*-1)
        #g = .05
        pass

    var thruster = self.get_node("Position/Gravity")
    var driver = self.get_node("Position/Rotation/Driver")
    var drive_vector = driver.get_global_transform().basis.z
    var drive_pos = driver.get_global_transform().origin
    var force_vector = thruster.get_global_transform().basis.y
    var force_pos = thruster.get_global_transform().origin

    if (Input.is_action_pressed("ui_up")):
        apply_impulse(self.get_global_transform().origin,(drive_vector*.5))
    elif (Input.is_action_pressed("ui_down")):
        apply_impulse(self.get_global_transform().origin,(drive_vector*-.5))
    else:
        #rotate_x(get_rotation().x*-1)
        #rotate_y(get_rotation().y*-1)
        #rotate_z(get_rotation().z*-1)
        pass

    if (Input.is_action_pressed("ui_left")):
        get_node("Position/Rotation").rotate_y(1*delta)
    elif (Input.is_action_pressed("ui_right")):
        get_node("Position/Rotation").rotate_y(-1*delta)
    else:
        pass


    pass

#Where artificial gravity is implemented after using the "Raycast" and utilizing the "Gravity" node that is
#the child of the "Position" node.

#The Gravity Node allows the vehicle itself to fall towards into an another direction rather than the usual
#default "Gravity Scale" Property, which is set to '0'.

func _integrate_forces(state):

    print(state)

    var thruster = self.get_node("Position/Gravity")
    var driver = self.get_node("Position/Rotation/Driver")
    var drive_vector = driver.get_global_transform().basis.z
    var drive_pos = driver.get_global_transform().origin
    var force_vector = thruster.get_global_transform().basis.y
    var force_pos = thruster.get_global_transform().origin

#   if (Input.is_action_pressed("ui_up")):
#       state.set_linear_velocity(drive_vector*10)
#       state.add_force(-force_vector*10*g, Vector3(0,0,0))
#   elif (Input.is_action_pressed("ui_down")):
#       state.set_linear_velocity(drive_vector*-10)
#       state.add_force(-force_vector*10*g, Vector3(0,0,0))
#   else:
#       pass
#
#   if (Input.is_action_pressed("ui_left")):
#       state.set_angular_velocity(Vector3(0,1,0))
#   elif (Input.is_action_pressed("ui_right")):
#       state.set_angular_velocity(Vector3(0,-1,0))
#   else:
#       state.set_angular_velocity(Vector3(0,0,0))

    state.add_force(-force_vector*50*g, Vector3(0,0,0))


    pass

The bottom line is that is there a way to make the Look_At () aim correctly towards a tilted ground so then the gravity would make the rigidbody fall/aim for the ground? This is something that could make it work in anti-gravity driving scenario.